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devilrmk
11-01-2009, 09:04 AM
Please tell us what you have learned about clutching. Asking questions about theory is OK also.

Keep posts about clutching THEORY not what one setup works with one sled.

EDIT BELOW (by milehighassassin)

I am adding this post that is compliments of dgreet77 (http://www.snowestonline.com/forum/member.php?u=65661) This is great info!
I'm working on trying to consolidate some basic clutching info to post up just to give beginners a place to start. I've got a bunch of stuff down that should do such a thing, but was wanting to make sure it was all correct. Not only this but anything you could add would be great.

Namely something that I would like to get more info on is how the spring rates affect things. EX higher first number on drive spring = higher engagement, etc. Also how to fix slippage when using heat to determine which clutch is slipping more.

Anyways here is what I have. Let me know. Thanks!


Primary Springs
• Use to control engagement
• Higher numbers = stiffer spring
• Higher first number = higher engagement
• Higher numbers generally = more weight needed
• Too high last number = incomplete shift
• Too low last number = too quick shift


Primary Clutch
• Use to control RPM’s via weights
• Use to control engagement via spring
• If hotter than secondary belt slipping more in primary

Flyweights
• Use to control RPM’s – more weight = less RPM’s
• Heel (close to pin) weight affects beginning of shift (slow speeds)
• Toe weight affects end of shift (high speeds)
• More heel weight = better low speed (crawling)
• More toe weight = better high speed

Secondary Springs
• Use to control backshift
• Softer spring = more up-shift = more MPH
• Stiffer spring = better backshift
• Stiffer spring keeps clutch in “lower gear” longer


Secondary Clutch
• Is torque sensing
• Use to control Backshift
• Up shift = clutch opening =increasing speed = shifting up/out
• Backshift = clutch closing =decreasing speed = shifting down
• If hotter than primary belt slipping more in secondary

Helix
• Use to control upshift
• Shallower angle (smaller number) = faster upshift and slower backshift

devilrmk
11-01-2009, 09:06 AM
I will start it off. First of all I don't know much about clutching.

I hear you guys talking about steeper helix angles. Correct me if I am wrong, the bigger the # the steeper the angle, correct?

krom
11-01-2009, 09:09 AM
Aaen has written what is considered to be the bible on clutch tuning, it is recommended reading by the OEM's for certified techs:
AAen's clutch tuning handbook (http://www.aaenperformance.com/Handbooks.asp)


buy it and leave it someplace you can read it over and over again

AKSNOWRIDER
11-01-2009, 10:21 AM
generally speaking, the heavier the primary weight/spring combo, the less sensitive the clutching is to elevation changes.......also the shallower the helix angles, the faster the back shift,but the slower the upshift also...;)

2XM3
11-01-2009, 10:22 AM
Yup, get his book, read about 4 times..only change 1 thing at a time and you will start to get a good feel of how it all works

XC700116
11-01-2009, 01:47 PM
Well, While I agree that everyone that is going to change anything on their clutching needs to read Olav Aaen's book lets get this conversation going and take the information base that is on this site and share it.

Here's some basic things to add to it Taken from Olav Aaen's Book

Keep in mind the are general and some things do and do not apply to different styles of clutches. For instance Team Clutches do not use a torsional spring only a compresion sping. Also there are effects of where weight is added to a flyweight weather heal or toe wieght is added also effects the shift.

Primary Clutch

Spring
The Pressure spring is listed by 3 properties: Enguagement Load, Full Shift Load, And Rate. Enguagement Load is the load the flyweight needs to overcome the spring and enguage the belt. Full Shift Load is the load the flyweigh needs to overcome at the end of the shift when the machine runs at top speed. The Rate of the spring controls the shift RPM during the shift and influences wheather the RPM increases, decreases, or stays the same during the shift.

The Flyweight
The flyweight has 2 properties used for tuning, the weight and the curvature. The weight influences how much RPM is needed to overcome the loads of the primary spring and the secondary clutch. Light weights need higher RPM and Heavy weights lower RPM. The curvature determines Enguagement speed and the agressiveness of acceleration.

Secondary Clutch

Spring
The secondary spring has a torsional and compression rate. Depending on the installed length and tortional load, the total spring load acting though the Helix determines shift out point, low ratio, and shift curve. Increaseing prtention load by moving the spring to different holes in the helix to give more angle pretension increases the RPM where the belt starts moving into the secondary sheave. The rate of the spring influences how the RPM changes during the shift. Higher rates will increase RPM at top speed. Springs are usually listed by tortional rate.

Helix
The Helix cam has only one property that we are interested in, cam angle. Angles are listed as either straight or progressive. In most cases cams start out with a larger angle to give harder acceleration at the beginning of the shift, at the end of the shift the angle is reduced to keep the RPM higher. By changing the angles the shift curve can be changed, small angles have higher shift speeds, larger angles have more aggressive shift out.

LRD
11-01-2009, 03:43 PM
An explanation of the effects of a compression only sec spring as to starting spring lbs, finish lbs and rate would be great.

Thanks

XC700116
11-01-2009, 05:47 PM
An explanation of the effects of a compression only sec spring as to starting spring lbs, finish lbs and rate would be great.

Thanks
they are about the same function just a different way about getting it in the case of the team clutches. Start and finish loads and the rate affect it in the same manner. ie higher rate and loads will raise RPM required to shift the clutch.

Barrett
11-01-2009, 05:56 PM
you should never use the sec spring to tune rpm. if rpms are not correct change the flyweight. If rpms are not correct durring backshift or ON/OFF throttle situations, then the helix angle/sec spring can be changed to correct the problem.

XC700116
11-01-2009, 07:04 PM
you should never use the sec spring to tune rpm. if rpms are not correct change the flyweight. If rpms are not correct durring backshift or ON/OFF throttle situations, then the helix angle/sec spring can be changed to correct the problem.
Agreed for the most part, I think what your getting at is not to use the sec spring to change your peak running RPM, however adjusting your finishing angle can work for your peak RPM but this is for during the shift than at full shift.

For example if your sled runs too high of an RPM during the shift but settles down to your desired RPM at top end then you should be increaseing the angle or lowering spring tension, likewise if your running too low RPM during the pull and then at top end finally reaches your target RPM you can choose either a lower angle helix or a stiffer spring.

It's a balancing act to achieve the disired outcome without creating a situation where the clutches are fighting each other. Attack each symptom individually and only make one change at a time. Up shift, Backshift, peak RPM, engagement.

winter brew
11-01-2009, 07:38 PM
I agree with tuning RPM with the primary and backshift characteristics with the secondary.....that's a little oversimplified, but a good guideline.
Another VERY informative and easy thing to check is sheave temperature. Make 1 pass on a deep hill. Lay your hand on the sheave surface of both clutches.....if 1 is noticably hotter/cooler than the other, you have some work to do, and that temperature tells you which clutch needs some attention. The hotter clutch is slipping more than the other. Finding a "balance" between both clutches is the key to clutching and when you have proper RPM, a straight shift, solid/quick backshift with little waiver in RPM and both clutches are runnign the same (or close) in temperature, you are making the setup more efficient. The result is cooler running and more power to the track :beer;
Now getting there is the fun part.

Barrett
11-02-2009, 10:06 AM
set engagment speed with primary spring and or notches in the flyweight
set running rpms with flyweight
set rate of upshift with helix angle selection
set backshift with helix angle/sec spring selection

Realise that any change effects almost every other area of the shift curve. It is a balancing act, but is scientific, not VOODOO.
The 2 components that have the GREATEST EFFECT are 1 the flyweight, and 2 the helix angle. the springs do very little.
The primary spring basically only effects engagement speed, the top rate of this spring has a neglegible effect.
The secondary spring basically just creates initial side pressure untill the helix can provide the side force from torque feedback through the driveline. The 1 area the sec spring does have significant effect is when off the throttle. In this situation it is the only thing backshifting the secondary, which is why stiffer sec springs feel more "revy" in on/off throttle stituations.
Do-Not try to use the springs to fix a shift curve that is not strait. use helix angles, or mass placement on the flyweight.

XC700116
11-02-2009, 10:20 AM
I agree for the most part except I do not agree that the finishing rate or top rate of the primary spring is neglegable, altough not a primary tuning point it does need to be at a resonable tension and with the wide variety of springs available tuners do need to pay attention to it. too heavy and you will never shift the primary out all the way and create heat, too light and you will be shifting it too soon and will create incresed heat due to the clutches starting to fight each other.

The same case can be made on the secondary spring as it does help control the aggressiveness of your helix angle selection and can be a great place for fine tuning to avoid the heat issue and develop backshift without hindering upshift. Like you say it's a balancing act not voodo.

And I also agree that your greatest effect is derived from Helix angle and flyweight mass and profile and that those are the place to start your tuning and correct major difficiencies.

Also I will be the first guy to admit that I am in NO WAY a master clutch tuner, 99% of my experience is with Polaris equipment and I am still gaining a complete understanding of the world of clutch tuning and especially with the Team Secondary as I've only been running them for about 4 years now. With the constant evolution of clutching technology and products we all need to keep learning.

XC700116
11-02-2009, 10:32 AM
Also if there's anyone out there that can shed some more light on the Flyweight Profile, Mass Placement and the application of these concepts PLEASE SPEAK UP This is one area where I personally am just starting to understand in more depth and there are others here that are way more educated in this particular area and I would love to learn more as I'm sure others would as well.

Some areas that would be helpful in that discussion are how different mass placement effects shift profile for different applications. For instance Big Bore torque monsters seem to like more heal weight whereas turbos do not.

Lets keep this discussion moving and expand on things as much as possible, while making sure the basics are covered.

ruffryder
11-02-2009, 11:13 AM
Weights and the flyweight roller interface.

Weights - consist of mass and specific profile
Roller - force interface between weight and clutch

Force pushing clutches into each other, direction defined as "x - axis"

So generally, you spin the clutch, the mass on the weights causes them to want to straighten out against the rollers (the whole rock on a sting thing...) and therefore once the force is greater then that due to the spring, the clutch will move.

The "force" is complicated though. What is the force? How do you change it? Well, that is an interesting one to talk about. First lets talk about the interface between the weight and the roller.

To push the clutches together, you need a force in the direction of the + x-axis. The primary spring applies a force in the - x-axis direction.

When the flywheel weights pushes on the roller, the force is not only in the + x-axis direction. The force is also in the direction of moving the roller away from the clutch center line (crank shaft center line also). Lets call away from center - line as + y-axis. The total force on the roller is due to the weight construction, the amount of mass, and the location of the mass. But, that is not all. There is something else that is more important (IMO) and that is the direction of the force.

If the force is ALL in the + x-axis direction (0 degrees), then ALL of the force is used to overcome the spring force and close the primary sheaths together. If the force is ALL in the +y-axis direction (90 degrees), then NONE of the force is used to overcome the spring force. Note that the x and y axis are 90 degrees apart. So, from this information, it can be assumed that if the force on the x-axis is equal to the y-axis, then the force is being applied at 45 degrees.

This is where the weight profile comes into play. The direction of the force onto the roller is perpendicular to the tangent of the surface of the weight touching the roller. So if the total force is kept constant, but the force direction (angle) is changed, then the amount of force applied to closing the clutch sheathes is also changed.

IMO, clutch weight profile is much more important then the actual amount of weight.

That is why the stock yamaha weights are like 65.2g or so for the Nytro MTX (stock, no rivets) with rivets about 70-75 or so grams, while the adjustable ones I have now are in the 55 gram range, but provide a more aggressive upshift. The weight profile creates more (usable) force with the 55 grams weights, as compared to the 70 gram weights.


One thing I would like to add is the whole, tune rpms with the primary only. That philosophy seems to only work when you are close to having the correct setup. Sometimes a too aggressive upshift in the secondary is the problem.

Hopefully some of that can be comprehended. That is my take on it..

Barrett
11-02-2009, 12:08 PM
IMO, clutch weight profile is much more important then the actual amount of weight.


One thing I would like to add is the whole, tune rpms with the primary only. That philosophy seems to only work when you are close to having the correct setup. Sometimes a too aggressive upshift in the secondary is the problem.


Agreed. If you are trying to fix an ailing tuneup, it is sometimes best to look back to the stock helix/spring combo, and tune from there.
if you are starting from scratch, you will definately have to approach tuning a little diferently. I like to start by selecting a sec spring/helix combo that has been used sucessfully on another combo similar in HP, and intended usage to what I am doing, and start there.

XC700116
11-02-2009, 12:50 PM
OK so now that everyone has X's and Y's confusing them :p I need to review my college physics books one of these days :(

care to add more specific info as to the effects of a flatter or more curved profile as well as a heal/toe weight bias in actual application. ie the meat and potatoes of the above explanation, heal weight does this, toe weight does that kind of a thing.

ruffryder
11-02-2009, 01:20 PM
As to weight and location, it is important to remember that clutches are like carburetors. Carbs work on throttle position only!!! That is the input into the system. For the primary clutch it is RPM only. Generally the way it works is more mass towards the heel (where the weight pivots) is for increasing the shift force at low shift out. The tip is generally for increase the shift force at full or high shift out.

XC700116
11-02-2009, 02:17 PM
As to weight and location, it is important to remember that clutches are like carburetors. Carbs work on throttle position only!!! That is the input into the system. For the primary clutch it is RPM only. Generally the way it works is more mass towards the heel (where the weight pivots) is for increasing the shift force at low rpms. The tip is generally for increase the shift force at high rpms.
That's pretty much my understanding as well but wasn't sure on it 100% as I'm sure there are more intricate effects involved when profile is concerned and I didn't want to shoot my mouth of on it if I wasn't sure.

thanks for clarifying and adding.


speaking of profile other than notches for adjusting engagement, I'm guessing that a flatter profile would give a little less "progressive" increase in force vs a more curved one.

ie: the flatter one has less angular advantage early in the movement than the more curved one of the same weight thereby being a less "aggressive" shift. I'm thinking this due to the above mathmatic explanation that ruffy gave.

Is this correct? Correct me if I am wrong please.

Barrett
11-02-2009, 02:38 PM
As to weight and location, it is important to remember that clutches are like carburetors. Carbs work on throttle position only!!! That is the input into the system. For the primary clutch it is RPM only. Generally the way it works is more mass towards the heel (where the weight pivots) is for increasing the shift force at low rpms. The tip is generally for increase the shift force at high rpms.

I have to correct you here - the bold should read shift ratio , as the weight in each position of the flyweight effects a certain part of the shift curve, and should still be tuned to run at shift rpms.
ex: if engine runs 8K, it should run 8k from start to finish, even though the heal of the flyweight effects the beginning of the shift(slow ground speed) , and the tip effects the end of the shift(high ground speed).
The secondary clutch needs to be tuned to create opposing shift force such that the engine(and flyweights) needs to be at shift RPM in order to overcome it, and therefore begin shifting out the clutches(and increasing ground speed).

ruffryder
11-02-2009, 02:48 PM
I have to correct you here - the bold should read shift ratio , as the weight in each position of the flyweight effects a certain part of the shift curve, and should still be tuned to run at shift rpms.

correct, thanks for the clarification. Yes, that statement should not say rpms but force at shiftout.

I have edited my post.

winter brew
11-02-2009, 03:43 PM
Sheave angle...both primary and secondary will have a huge impact on setup. For example, the Hyperlite sec had a fairly steep sheave angle.....makes for less belt squeeze compared to most sec's if using the same spring/helix angle. Made for a quick upshift and less backshift signal...good drag race clutch.
I think just about every primary and sec is running a different angle so it's one more thing to think about when tuning.....and the TRA primary has a variable/progressive angle.

shortstop20
11-02-2009, 03:45 PM
What angle do the sheaves start and end at on the TRA winter brew? The TRA has a steeper sheave angle than the P85 if I remember right?

winter brew
11-02-2009, 03:52 PM
I believe it's still 24-28.....but memory is bad.

thefullmonte
11-02-2009, 08:18 PM
OK so now that everyone has X's and Y's confusing them :p I need to review my college physics books one of these days :(

care to add more specific info as to the effects of a flatter or more curved profile as well as a heal/toe weight bias in actual application. ie the meat and potatoes of the above explanation, heal weight does this, toe weight does that kind of a thing.

I'll take a little stab at this. Please note there are many ways to get to the same end with clutching. As well your riding style comes into play. This is what I have found to work for me lately. However, it seems I'm always tuning and learning. Remember....baby steps. :p Oh, and I especially want to thank AKsnowrider and Winter Brew for helping me out over the years.
I assume you are referring to something like the Heavy Hitter weights from Thunder Products or the MTX from SLP. The heavier weight in the pivot area will allow more belt squeeze at lower RPM. This has been said. What does this do really? It allows you to use the full gear ratio provided by your sheave faces. Standard (Polaris type)weights slip quite a bit at low rpm and actually require more rpm to positively engage the belt. So what most people do is go to a very steep initial angle on their secondary. Why? So the primary can shift through the secondary very quickly. This allows the clutch to move to a higher gear where it is less likely to slip and you are now into a ratio and rpm the clutch weight can perform at more efficiently. With a heavy pivot weight you have positive force on the belt so it can engage and pull smoothly at lower rpm as well pull less angle of helix. This gives you a nice low crawling gear without trenching.
Adjustable weights tend to also have a center hole and tip hole. As also stated earlier the tip hole will have the greatest effect on overall rpm. Now here comes a BUT. For most mountain applications we tend to like a very aggressive up shift. So if the heavier pivot weight already has things moving. Lets just add some to the center to control our up shift characteristics. Please note that I'm not taking into account weight angle. Now if you need more top speed you tend to move more weight to the tip. If you are running a few RPM shy you can take weight out of the tip.
I was on the phone with Lon from Thunder products today (Heavy Hitters) :D He gave me a bit of a, OK a huge refresher course ;) . Now something I've always known, but sorta forgot is that the secondary isn't a clutch at all. It is a torque converter. It senses torque being applied to it from the primary during acceleration and from the track during deceleration. That may help a bit for some of you.
I hope I got all that right :rolleyes:

XC700116
11-02-2009, 10:50 PM
Sounds about right and yeah the Heavy hitters or a MTX style weight is probably the angle most would be looking at for adding or removing weight from a certain area. I personally will be working with a set of lightning weights and primarily removing weight from the heal due to the turbo application. I may also pick up a couple sets of 10 series weights and grinding on them to play with the profile a little.

and yes technically the secondary is a torque converter and not a clutch but clutch is easier to type :D

Lets keep this thread going, the more info the better and like has been stated there's more than 1 way to skin a cat.

Funoutfitters.com
11-03-2009, 09:23 AM
If you guys have questions on clutching, feel free to use our website, and you can talk to cat master techs free of charge!!


Josh Zieske

XC700116
11-03-2009, 11:52 AM
We are trying to build an informative thread for people to use as an educational tool and get the info out there to those that want to learn it.

Thanks for the offer and the info for those that are looking for a direct answer on a specific problem especially as it pertains to Arctic Cat sleds this is a great tool, but I don't think we would want to tie up your application and your technition by giving the quiz show to him for hours on end either.

If you could please have one of your guys come in and participate in the discussion from time to time, always looking for different viewpoints and info on different applications. I would ultimately love to get a Cat, Doo, Polaris, and Yamaha specialist in here to contribute to the thread.

XC700116
11-03-2009, 11:54 AM
Oh and I'm not trying to lay claim to the thread just trying to help it along and keep it going.

devilrmk
11-03-2009, 07:31 PM
This is exactly what I was hoping for in this thread. Keep it up guys.


You are doing just fine XC

www.team-ind.com
11-04-2009, 08:43 PM
To build on the theme of a secondary clutch being torque sensing, attached is a link to the spreadsheet that we posted on the Mod board that shows belt side pressure at WOT with either a TEAM TSS-04 clutch or a Tied Secondary clutch. With this you can see the big changes that a helix can make in side pressure and the relatively small changes a spring makes. Like previous posters have said, first tune with gram weight and helix angle and fine tune with springs.

BTW the other reason higher helix angles at the start of the shift curve work well is that there is a lot more belt in contact and thus less side force needed.
http://www.snowest.com/forum/showthread.php?t=172390

Mark Schiffner
TEAM Industries

sunbather1969
11-05-2009, 01:01 AM
We are trying to build an informative thread for people to use as an educational tool and get the info out there to those that want to learn it.

Thanks for the offer and the info for those that are looking for a direct answer on a specific problem especially as it pertains to Arctic Cat sleds this is a great tool, but I don't think we would want to tie up your application and your technition by giving the quiz show to him for hours on end either.

If you could please have one of your guys come in and participate in the discussion from time to time, always looking for different viewpoints and info on different applications. I would ultimately love to get a Cat, Doo, Polaris, and Yamaha specialist in here to contribute to the thread.

thanks for the offer but give some input instead of output

likkerpig
11-05-2009, 10:46 AM
Great thread! Here's something I'd like to know (and it's probably not a cut and dried answer, but I'll just put it out there...)

Say you have a motor spinning 8100 RPM and you want to raise or lower the RPM. How many RPMs per gram of weight can you shoot for when tuning clutch weights? For example, say if you wanted to drop 300 RPM, how many grams lighter/heavier would you need to go? 2g? 3g? Is there a constant "formula" where Xgrams = Xrpms?

(Also realizing you could maybe try and adjust that via primary spring with a stiffer finish rate...)

shortstop20
11-05-2009, 10:51 AM
There's really no set formula. Just have to go try it. I've seen peak RPM stay the same with heavier weights.

XC700116
11-05-2009, 10:56 AM
There's really no set formula. Just have to go try it. I've seen peak RPM stay the same with heavier weights.
This is really dependant on the spring your running and what kind of clutch your dealing with. "normally" and with a "normal" spring on a polaris P-85 I've seen an average of about 100 RPM to 2 grams of weight/arm. Now that is a very vague answer I know but it is very dependant on many other variables. but as a general rule of thumb it's pretty close on a setup that is "pretty close" to a good running setup, ie everything is pretty good except it overrevs just a touch.

astro
11-05-2009, 11:02 AM
How fast do you like to hit your max RPMs when you go from idle to WOT? It's the starting helix angle that effects this right?

XC700116
11-05-2009, 11:15 AM
How fast do you like to hit your max RPMs when you go from idle to WOT? It's the starting helix angle that effects this right?
That's kinda a question that is very application/riding style specific. Some people or circumstances require max hp immediately and some torque. Some will want to hit their Max RPM immediately while some will want it to climb to it after launch.

Drag racing you'd normally like to get to your peak torque RPM right out of the gate and then rev to peak hp as the shift progresses.

From what I've seen and what I prefer this is about what I shoot for on most any NA sled while trying to keep a good backshift/in and out of the throttle response.

Initial helix angle does effect this aspect as well as the other components of the system but that is one of my main areas of focus when going for the goal I just mentioned.

Most of the entire clutching formula is dependant on what your doing with the sled, and the running characteristics of the motor. NA 2 strokes you want to utilize the bottom end while on turbo applications you normally want to get the motor on boost ASAP so both require a different approach. This is where knowing where your motor makes hp and torque are abosoluetly critical.


Astro, your sled is a pretty special animal, I'd love to hear some of the things you've found to work while tuning that monster.

astro
11-05-2009, 11:51 AM
Been having a few belt slippage issues but hopefully I will get them taken care of this year! Going through the whole sled right now- New T35r turbo to try this year. Should be done dialing the M10 in also. Running the new Motec knock module this year also.

Back to clutching, my motor makes lots of torque at low RPMs and lots of HP at the top. Been playing with the Paragon for a while. Got a new helix to try as soon as the snow hits, but ready to move to a different secondary if it doesn't solve the slippage issues. Maybe I'll try the Team Tied.

XC700116
11-05-2009, 01:25 PM
I know a guy that had great luck with his paragon but I haven't messed with them at all and he's not running anywhere near the HP that you are. Best bet on that is to talk to Duane about it but he's not always easy to get ahold of.

Sounds like the Tied can provide you with some pretty serious belt pressure though so that might be the best route.

winter brew
11-05-2009, 01:33 PM
How fast do you like to hit your max RPMs when you go from idle to WOT? It's the starting helix angle that effects this right?

IMO, from idle to WOT, RPM should go almost immediatly to PEAK....maybe 1/2 a second...??

astro
11-05-2009, 02:01 PM
Been talking with Duane, it sometimes takes a long time to get a new helix so tunning takes a while

Funoutfitters.com
11-06-2009, 08:30 AM
feel free to check out our website, and chat with online certified cat master technicians....

Josh Zieske

devilrmk
11-06-2009, 10:13 AM
feel free to check out our website, and chat with online certified cat master technicians....

Josh Zieske


Josh,
Please read the first post in this thread again before posting. What you are doing is not what we want on this thread.

mattymac
11-10-2009, 11:43 PM
what about gearing and how it affects clutching?

Norway
11-11-2009, 01:31 AM
what about gearing and how it affects clutching?

Just Q mattymac. My performance source, with multiple drag- and sno-x wins to his credit, always complain that customers call, ask for a clutch kit and when he ask if anything has been done to the sled they say; no, just geared it down. His reply is always; "no, I dont have a clutch kit for you if you've geared it down".

RS

Norway
11-11-2009, 01:44 AM
After I read Aaens book and saw how the secondary work with the helix, I always thought of it as threads on a bolt. The helix angle compared to a fine/coarse thread.

This way I see the balance as the engine trying to "un-screw" the nut from the bolt (opening) while the resistance from the driveshaft/track being the oposite force trying to screw in the bolt into the nut, ie closing the secondary.

does this make any sense?


RS

winter brew
11-11-2009, 10:38 AM
Lower gearing typically DROPS some RPM....and taller gearing GAINS RPM.
When I am gathering info for a clutch setup, gearing is ALWAYS a factor.....what style rider are they, where do they ride, track lengh and more importantly track weight...engine mods etc...
I am a fan of fairly low gearing for the mountains (but not TOO low) because lower gears will put the belt higher in the primary at any given speed. This gives more belt/sheave contact area which makes for less slippage (less heat) and also gets us closer to a 1:1 ratio...which is where a CVT system is most efficient.
There are other with different theories on clutching/gearing but this has always worked well for me.

ruffryder
11-11-2009, 10:45 AM
I am a fan of fairly low gearing for the mountains (but not TOO low) because lower gears will put the belt higher in the primary at any given speed..

Define "too low" please. Is it possible, like are there actual gear combinations out there to get "too low" ? Just curious what some problems could be.

Thanks. I too am a fan of low gearing. I could care less about trail ride speeds..

winter brew
11-11-2009, 12:44 PM
Too low and things become TOO sensitive. Too low and your belt moves up/down the sheaves more with speed changes....more movement up and down the sheaves means more potential for heat so there is a fine balance in there somewhere....2.00-2.35 seems to be where most mountain guys end up depending on track length, power, riding style etc..

shortstop20
11-11-2009, 12:56 PM
I agree with Winter Brew.

Olav Aaen has some good comments about gearing in his book. He says to shoot for a gear ratio that will put your clutches at a 1:1 ratio where you do the most of your riding. Since the clutches are most efficient at this ratio, it only makes sense to use that ratio as much as possible.

I did this on my Pro-X and it worked quite well.

mattymac
11-11-2009, 08:40 PM
I was just amazed that 3 pages of this stuff and gearing was never spoken about.

I like doing the old sharpie trick in the sheaves to make sure im getting full shift (not to high geared) getting full shift and utilizing 100% of the CVT.

Jeff K
11-19-2009, 11:12 AM
Some good (free) reading here: http://www.gates.com/index.cfm?location_id=3850

ruffryder
11-19-2009, 02:44 PM
snowtech (http://www.snowtechmagazine.com/articles/2001/clutch/cltchtun.php)

Rprecision
11-19-2009, 04:22 PM
Belt deflection ?

Side Belt Clearence ?

I can always tell when I jump on a sled if the belt deflection is jacked up. Starting in a higher gear ratio induces bog, poor belt life and throttle response.

Great thread keep her going

Norway
11-28-2009, 02:24 PM
Belt deflection is very important. To much or to little, same result. Your "missing out on gears", so to speak.

To much deflection is caused by 3 things: wrong belt (to long/narrow), C-C distance wrong or incorrect setting/shimming of the secondary.
Ti little is the same, except to wide or to short instead of long/narrow.

To much and your belts creeps way up on your primary before being caught by both sheaves. To little and your belt never reaches the top of your secondary clutch.

It all takes away from both starting and full shift ratio.


RS

stonehands
11-29-2009, 11:56 PM
Ramble bamble...blah blah blah. SOMEONE JUST GIVE THE PERFECT SETUP FOR ALL CONDITIONS ALREADY!!! Nah just kiddin! AWsome thread. Personally I like a sled that upshifts like a drag racer myself. They just seems snappier and funner to ride. (of course that also describes why I think Cats are so boring to ride) excluding insanely boosted ones. Not sure if they feel so lazy cuz of the motor design or the clutching.
Love the way my Xp holz clutching upshifts. It's a blast when you wheelie up and your track zings up to 60 mph its almost out of control feeling. But that makes my point. Clutching is so much rider preferance and riding style. My setup can be very sensitive to changing snow conditions b/c it is very upshift oriented but I'm Ok with it b/c I understand it and know what to change to make it work better.

I think Winterbrew said it best so far in my opinion. Gearing for the kind of riding you want to do so as to optimize CVT ratio is key.
It is a fine balance between not enough side pressure on the belt (ie. slippage and heat) and to much belt pressure so the primary is fighting to open the secondary while trying to upshift.
All in all I think clutching is one of the funner parts of sledding. It never gets boring trying to perfect the almost unperfectable.
Great thread.

LRD
12-03-2009, 01:17 PM
The most amazing thing I ever learned about clutching happened by accident back in 05. Was wining to a friend about how doggone much harder sidehilling my new 05 summit 550 fan was compared to the old Phazer mtns. He suggested putting in a high rate primary spring (130/280) HUH? So I buy about five springs 100/260, 100/280, 130/280, 130.320, 160/280 etc. The one that worked amazing was the 130/280 and 100/280 for the wifey. Works for sidehilling because when the front end starts washing out downhill, just a little burp of the throttle gets max R's and breaks the track loose and rear of sled washes out and is level with front end again.

BUT the other thing it does is the High Rate (short spring, fat wire) with lower lbs at engagement allows clutch weights to generate more belt squeeze so the sled will literally tractor along through the powder at 5 to 12 mph without breaking the track loose. This is if you set up with lower engagement
RPM.

Fixes that track everybody was complaining about a few years ago.

The 100/280 on the wifes sled is because she doesn't get stuck anymore and I can ride more. It will tractor along at near 15 mph before it tips over and snaps to shift RPM.

Takes a little experimenting to get the right spring that you like but well worth it. Kind of like having two different clutching setups or ratios in one clutch setup, low and high. The 160/280 on my 385 lb 629 fan mod was nuts, burp throttle at 15 mph and skis were two feet in air, where stock style springs couldn't get front off the snow to save your life or jump a log. One of my complaints on that sled (no weight transfer) turns out to be the primary spring not the rear suspension, sure surprised me. Never ran that spring in the powder as I felt it was to aggressive.

I currently use a high rate on my 380 lb 08 mod mtn TNT and friends use it on 800R's, old mod MXZ big bore triple etc., it just flat works!!!! Makes for a fun to ride sled!!!

These high rate style springs are just the opposite of a lot of doo stock springs over the years, the ones that look like you could put them on a front shock in a pinch cause they are so long!!!

Good Luck

PS Going back to our first trips to the Mtns in late 80's with short track Phazers would have been a whole lot more fun with high rate (lower engagement rpm) primary springs instead of the factory higher engagement rpm springs for high altitude. Wouldn't have been trenching near as much. Factory theory was make up for lower HP at engagement with more R's at engagement mine now is do it with lower gears, max track speed in powder isn't much over 50 mph with anything except turbo's anyhow.

drop the hammer
12-04-2009, 12:13 PM
Another comment on gearing lower. Not only does it put the belt up higher in primary, it also puts you up further along the helix profile, so if it's a progressive cut, your on a different angle now which will have a similar effect as changing helix and very little bit...possibly at a lower angle depending on the helix profile of course. Also on primary clutch your rollers will be further along the ramp face and also at different angle.
Sounds good to me to be as close to 1:1 as possible when in the hill climbing (for me as a mtn rider). I also like the sounds of running lighter pin weight when gearing down, since this would give even better backshifting....I guess one has to balance the cost of these changes to the benefit as changing top gear is relatively cheap, but bottom gear and chain gets spendy. Most guys i talk to get the most performance gain out of a clutch kit, then the gearing is more tuning/tweaking type of stuff at an extra expense....but some of us just can't leave well enough alone. ;)

drop the hammer
12-04-2009, 12:20 PM
Does anyone know at 50 mph on gearing of 21/49 how close am i to 1:1 shift? stock drivers XP 163. What gearing would get me to 1:1 at 50 mph? I don't care about top speed or lack of speed. In theory that should be the most efficient, correct? But now with my stock gearing on 3 back to back hard long pulls in 3 feet of snow, my clutches are just warm and I can hold them as long as I want comfortably (I use them to warm my hands, i'm such a puss). So why should I regear (other than to experiment)? Doesn't sound like I'm slipping belt regardless if I'm not at 1:1....something to discuss. Would 1:1 be better than what I have?

Norway
12-04-2009, 03:44 PM
Does anyone know at 50 mph on gearing of 21/49 how close am i to 1:1 shift? stock drivers XP 163. What gearing would get me to 1:1 at 50 mph? I don't care about top speed or lack of speed. In theory that should be the most efficient, correct? But now with my stock gearing on 3 back to back hard long pulls in 3 feet of snow, my clutches are just warm and I can hold them as long as I want comfortably (I use them to warm my hands, i'm such a puss). So why should I regear (other than to experiment)? Doesn't sound like I'm slipping belt regardless if I'm not at 1:1....something to discuss. Would 1:1 be better than what I have?

1,5 to 1 assuming 8000rpm, 3" pitch and 8 tooth drivers.

RS

winter4ever
12-07-2009, 11:01 PM
Great thread! I have been researching for quite some time now and it is hard to find a direct answer to a pretty specific question that I always fumble with.

About the team helixes. I always get confused on what all the numbers mean and how they will effect performance. for example, my sled has 56-42-.36
As I understand it (and I could have things a little backwards here) the 56 is the initial angle, the 42 is the finish angle, and the .36 is the percentage of the total that the initial angle holds?? could someone shed some light on this for me? also what effect will changing each of these numbers have on performance?

winter brew
12-07-2009, 11:17 PM
Great thread! I have been researching for quite some time now and it is hard to find a direct answer to a pretty specific question that I always fumble with.

About the team helixes. I always get confused on what all the numbers mean and how they will effect performance. for example, my sled has 56-42-.36
As I understand it (and I could have things a little backwards here) the 56 is the initial angle, the 42 is the finish angle, and the .36 is the percentage of the total that the initial angle holds?? could someone shed some light on this for me? also what effect will changing each of these numbers have on performance?

You have it right. That first angle (56) progresses to the 2nd angle (42) for the first .36 inches of ramp travel....the first is only 56 degrees initially and is progressive to the 42....if that makes sense.
Steeper angles load the engine harder (upshift quicker) but have slower/weaker backshift and less belt squeeze. Opposite with shallower angles.

Norway
12-08-2009, 08:36 AM
New question: how far up in the secondary can you have your belt? Just the "cooling fins" above the sheave or can you go a bit further?

I ask because I'm messin with a P-85/Bearcat combo. Thought the belt would never see the bottom of the secondary, but I blew a couple of belts last season and when I took it apart for cleaning, the shoulder was smeared black..

RS

winter brew
12-08-2009, 10:04 AM
New question: how far up in the secondary can you have your belt? Just the "cooling fins" above the sheave or can you go a bit further?

I ask because I'm messin with a P-85/Bearcat combo. Thought the belt would never see the bottom of the secondary, but I blew a couple of belts last season and when I took it apart for cleaning, the shoulder was smeared black..

RS

As high as you want (within reason), as the belt will drop lower into the sheaves as soon as the sled moves.

Norway
12-08-2009, 01:32 PM
As high as you want (within reason), as the belt will drop lower into the sheaves as soon as the sled moves.

It's that "within reason" thing I'm asking about ;) Just the cooling ribs or 1/4"??

RS

joshkoltes
12-08-2009, 03:16 PM
is a polaris almond pri spring the same rate as a gold?

winter brew
12-08-2009, 08:35 PM
It's that "within reason" thing I'm asking about ;) Just the cooling ribs or 1/4"??

RS


IMO if you have at least 1/2 of the belt thickness with sheave contact you will be fine.

RockyMtn.Kris
12-14-2009, 08:35 PM
Great thread! I have been researching for quite some time now and it is hard to find a direct answer to a pretty specific question that I always fumble with.

About the team helixes. I always get confused on what all the numbers mean and how they will effect performance. for example, my sled has 56-42-.36
As I understand it (and I could have things a little backwards here) the 56 is the initial angle, the 42 is the finish angle, and the .36 is the percentage of the total that the initial angle holds?? could someone shed some light on this for me? also what effect will changing each of these numbers have on performance?



I know Winterbrew answered your question, but just to add a little tid-bit you can change the .36 (manipulate is probably better) by shim stacking the secondary spring. Adding a shim can do two things for you; 1 it adds pre-load to the spring and 2 it will shorten the distance of the initial angle

RockyMtn.Kris
12-14-2009, 08:46 PM
Does anyone know at 50 mph on gearing of 21/49 how close am i to 1:1 shift? stock drivers XP 163. What gearing would get me to 1:1 at 50 mph? I don't care about top speed or lack of speed. In theory that should be the most efficient, correct? But now with my stock gearing on 3 back to back hard long pulls in 3 feet of snow, my clutches are just warm and I can hold them as long as I want comfortably (I use them to warm my hands, i'm such a puss). So why should I regear (other than to experiment)? Doesn't sound like I'm slipping belt regardless if I'm not at 1:1....something to discuss. Would 1:1 be better than what I have?



You are probably closer to 2 to 1 than 1 to 1 in this example. If you truly geared to be at 1 to 1 (secondary loaded) the sled would be miserable to drive down the road. Everbody talks about getting closer to that ultra-efficient ratio of 1 to 1, and granted that is the most efficient, but if you look at efficiency charts 2 to 1 is exponentially better than 3 to 1. You could gear for one specific condition but the trade-off isnt worth it imo.

revvers69
12-15-2009, 12:26 PM
HI,
I just bought a2004 viper mountain with a 159 polaris skid. I am running heel clicker weights and am wanting to know what to run for the higher elevations. Right now on flat land Iowa style 8500 r's at about 70mph. I havent pulled the weights out yet to weigh what grams are currently being run in the shoulder center and tip. Just wondering what would work for the mountains thanks...

devilrmk
12-15-2009, 11:23 PM
Post in the Yammi section. You will get more answers. This thread is intended for clutching theory, not clutching recommendations.

Ron
12-20-2009, 10:26 AM
Great thread!

When you think clutching is right then a good test is to check RPM/backshift on different snow surfaces. Run from groomed to deep snow-clutch should backshift quickly, R's return quickly. Try a hill in deep snow, let off throttle get back on it.
Some put too much emphasis on RPM-just because you are running the right R's doesn't mean you are getting max performance. We have two other tests when we think we are close-first is to increase weight in the primary until it pulls down R's. At that point you know you can't pull more weight(without other changes). For most conditions more weight in the primary means the clutching is less affected by altitude and snow conditions-less finicky. Second is to test against another sled and in different conditions so you can see actual results of changes..."Seat of Pants" can lie.
There are some good points on mass location vs shift charactoristics/RPM. All mass has some affect on the shift. If you think of the bolt as the fulcrum point (pivot point) it's easier to visualize why the location of mass affects shift charactoristic's based on location. The further the mass from the fulcrum, the more force exerted at higher R's. The closer the mass to the fulcrum point the less force exerted at higher R's. You can make some significant changes in clutching simply by repositioning mass in weights. SkiDoo's TRA has a fixed, yet movable ramp so it's a different animal.

Edit: One more thought....the driven "torque converter" can run into extreme conditions beyond it's ability to function properly without clutching changes. In our area, the Rockies, we normally have dry powder with some wet heavy snow in the fall and spring. With wet heavy snow you have two factors at play-a lot more "load" from the track and heavy rolling resistance from the chassis. An easy fix is to change the helix angle a couple degrees shallower on a Polaris. I run a custom helix from Carl's that has the two cuts I need. It's an easy change that can be made in the field on the Poo.

papafinger1
12-21-2009, 10:14 PM
I will be the first to admit that I no absolutely nothing about clutching other than the suggestions given by oem charts and fellow sw'ers. I recently spent 2 very informative hrs with Lon from thunder products discussing gearing, primary clutching, and the torque converter/ secondary. He broke the tuning process down into terms that I was capable of understanding. Many views he has conflict with some here but nonetheless I am able to comprehend the terminology you are all using thus gaining knowledge about clutching theory. Thanks to Lon and all of you I feel I have the ground works set to confidently and successfully clutch my home built turbo. Although this yr will be spent developing a turn key set-up, next yr I will concentrate most of my efforts into clutching. Thanks again and continue to improve my clutching IQ....

Spiderman
12-30-2009, 08:25 PM
Great thread! I want to throw out an example. Lets say your clutches are creating a lot of heat equally. (p85, older team clutch) The sled starts out at 8100 and drops rpms on a long climb down to about 7700. On trail it climbs rpms, 8000 on intial full throttle settles to 7500 at about 40 to eventually climb to about 8000 rpms. So, one change at a time, you would either use less angle on the second angle of helix or use lesser lbs in the secondary spring on the finish top number to give more force on the belt in the secondary? That's assuming everything else is aligned and working properly with new springs, weights, and belt with proper gearing. It also has lots of low end grunt and no trenching.

winter brew
12-30-2009, 10:01 PM
Great thread! I want to throw out an example. Lets say your clutches are creating a lot of heat equally. (p85, older team clutch) The sled starts out at 8100 and drops rpms on a long climb down to about 7700. On trail it climbs rpms, 8000 on intial full throttle settles to 7500 at about 40 to eventually climb to about 8000 rpms. So, one change at a time, you would either use less angle on the second angle of helix or use lesser lbs in the secondary spring on the finish top number to give more force on the belt in the secondary? That's assuming everything else is aligned and working properly with new springs, weights, and belt with proper gearing. It also has lots of low end grunt and no trenching.

Close.....except you would want MORE secondary spring force to give more belt squeeze/more RPM. Or just drop a litlte primary weight.

Spiderman
12-30-2009, 11:28 PM
I originally thought it would be more force but then I looked at the spreadsheet http://www.snowestonline.com/forum/showthread.php?t=172390 and changed my mind. I still mustn't be reading it correctly. Is the side pressure in the chart the same as sheave pressure against the belt? So my team red black at 140/240 I could change to say to a 160/260 and that would squeeze the belt tighter or would I want to go to the 180/280 to see a definite change? I am hitting my rpm target but it doesn't stay there because of heat (long climb) or not quick enough of backshift.(long flat straightaway on trail) The team uses only compression force while the regular polaris secondary uses torsion to make the compression on the spring somewhat adjustable?

RockyMtn.Kris
12-31-2009, 01:08 AM
I originally thought it would be more force but then I looked at the spreadsheet http://www.snowestonline.com/forum/showthread.php?t=172390 and changed my mind. I still mustn't be reading it correctly. Is the side pressure in the chart the same as sheave pressure against the belt? So my team red black at 140/240 I could change to say to a 160/260 and that would squeeze the belt tighter or would I want to go to the 180/280 to see a definite change? I am hitting my rpm target but it doesn't stay there because of heat (long climb) or not quick enough of backshift.(long flat straightaway on trail) The team uses only compression force while the regular polaris secondary uses torsion to make the compression on the spring somewhat adjustable?



I am unable to open the chart:confused:,but I will try to answer. You will see a change in rpm anytime you make a change to spring pressure. Keep in mind that with no other changes, reducing helix angle will increase side pressure against the belt and improve backshift.

On the Team vs a Polaris secondary, the Team functions more linear where the button stlye has more resistence. The torsional force helps to overcome this. Somewhat adjustable yes, each hole you tighten the spring, you increase preload which will increase rpm in increments

Barrett
12-31-2009, 12:37 PM
I originally thought it would be more force but then I looked at the spreadsheet http://www.snowestonline.com/forum/showthread.php?t=172390 and changed my mind. I still mustn't be reading it correctly. Is the side pressure in the chart the same as sheave pressure against the belt? So my team red black at 140/240 I could change to say to a 160/260 and that would squeeze the belt tighter or would I want to go to the 180/280 to see a definite change? I am hitting my rpm target but it doesn't stay there because of heat (long climb) or not quick enough of backshift.(long flat straightaway on trail) The team uses only compression force while the regular polaris secondary uses torsion to make the compression on the spring somewhat adjustable?

Heat equals, slippage, and/or alignment problems. I assume you have checked and corrected all alignment problems. after reading you posts I think you could start by going to the 160/260 sec spring, and if that doesnt help then you need less helix angle from start to finish. after you get the heat under control, then work on the flyweight/primary spring to get revs correct. my .02

Spiderman
12-31-2009, 07:56 PM
Thanks for the info. I'll give the higher rate spring a try first. I assume the linear spring and roller design of the team is supposed to have less resistance than one that is torsional also? Also, I see the chart is for the new team tied clutch. Can somebody explain the chart? The end result is the side pressure on the belt. How does that tell you what helix and spring to use? By finding the combination of new helix and spring that produces the same force in the same shift point of your old set up?

winter brew
12-31-2009, 09:47 PM
I originally thought it would be more force but then I looked at the spreadsheet http://www.snowestonline.com/forum/showthread.php?t=172390 and changed my mind. I still mustn't be reading it correctly. Is the side pressure in the chart the same as sheave pressure against the belt? So my team red black at 140/240 I could change to say to a 160/260 and that would squeeze the belt tighter or would I want to go to the 180/280 to see a definite change? I am hitting my rpm target but it doesn't stay there because of heat (long climb) or not quick enough of backshift.(long flat straightaway on trail) The team uses only compression force while the regular polaris secondary uses torsion to make the compression on the spring somewhat adjustable?


What helix angle are you running? What is the "other" angle on your helix?...provided it has two tracks like most TEAM helix's.
If you can go to a shallower angle try that first. You can also try a 140/260 or 160/260 spring but ideally you want to run as little secondary spring as possible and still get adequate backshift...you don't want to go too stiff or you'll get alot of heat and poor upshift.
The helix itself provides the majority of belt pressure .....the spring is mainly a factor at low speeds, diminishes as speed increases.
You may try just dropping a small amount of primary weight or a little more primary spring finish rate. Are both your springs in good condition right now??

Spiderman
01-01-2010, 12:25 PM
Hey brew, been riding yet? I have the 54-38.36 and the springs were new last year. That's what I was looking for that the helix provides most of the belt pressure and the spring is in more effect at low rpms. I'm stlill learning in the clutching department. I think I am in the shallowest angle finishing angle but I'll check that. My weights are 10-58 with cpi twins and head on an 01 800 so it should be able to pull them, but we have been at 10,000 ft alot, so maybe I'll have to change them

Eli
01-02-2010, 11:31 AM
On gearing, the lower you are geared the less secondary side pressure is needed due to the decreased load on the secondary.

I believe most sleds could work more efficiently with less spring in both the front and rear clutches. It seems like we are in a snowball effect with clutching...heavier spring needing more weight needing more spring needing more weight, more secondary spring needing more primary weight to pull it open needing more primary spring to offset the weight....and on and on. I personally run a very light setup and have even seen a light primary setup/team secondary on a mostly stock dragon work at least as well as the stock weights. Big weights with big springs don't necessarily "grip" a belt better than light/light setup. I hope I am not off base on this thread.:)

Has anyone converted their sleds to a lighter setup?

bigjb
01-03-2010, 10:52 PM
So how would you answer this question in theory. On the flats sled shifts out fast up to peak say 8000 rpm, but settles down to 7300 and will not gain from there. On a hill in the trees (on and off throttle) it will be responsive but will fade and eventually bog out. On a straight hill climb it will act like on the flats but will not hit peak in powder only in harder snow. Track speed is decnet on a hill, 40mph for only 7300 rpms. This is on an m7 by the way. Am I wrong in assuming that there is too much spring for the cam angle in the secondary not allowing it to fully shift out?
Another question being can you use a steeper cam angle to overcome a stiff spring?

RockyMtn.Kris
01-04-2010, 10:34 AM
So how would you answer this question in theory. On the flats sled shifts out fast up to peak say 8000 rpm, but settles down to 7300 and will not gain from there. On a hill in the trees (on and off throttle) it will be responsive but will fade and eventually bog out. On a straight hill climb it will act like on the flats but will not hit peak in powder only in harder snow. Track speed is decnet on a hill, 40mph for only 7300 rpms. This is on an m7 by the way. Am I wrong in assuming that there is too much spring for the cam angle in the secondary not allowing it to fully shift out?
Another question being can you use a steeper cam angle to overcome a stiff spring?


Sounds like too much helix and or spring pressure.

On the second question, the steeper the angle the less side pressure. You dont want to use one to try and compensate for the other. Together the two need to match the side pressure requirements of the belt

Clarke_67
01-04-2010, 10:53 AM
I have a TSS-04 clutch in my IQR 800. It has a rattle when you shake the clutch in the air and it has TERRIBLE backshift all of the sudden. I am going to assume that my ramps are wore out or a broken spring. Also, when i take the belt of useing the team tool, the clutch only closes half way? I guess i will swap it out for my older team clutch for now but i realy want to figure out how to get this TSS-04 clutch to work the way it should.

So my question is, i have a 56-38 ramp... What charectoristics should it have as far as backshift? To me, i would rather have better backshift than an explosive sled.

Thunder101
01-04-2010, 03:22 PM
One thing not mentioned much yet is cam profile- steeper ramps creating stronger or harder shifts. flatter angles making for a slower smoother feeling shift. Dr spring can effect shift force also, # of lb per inch if a Dr spring has say a 140- 260 vs 140-320 this will also effect speed of shift .

Ive read Aaens book 10-15 times years ago and it is a great book for the can.lol. you cant read it to many times.
Ive clutched all my sleds Ive owned and have had good luck and enjoy it.

Some steps on how to start to clutch your sled. -btw I dont know it all or the 1/2 of it but that heading will help me get some good feed back.lol
-constructive criticism please. :)
I ussally throw weight at it till the desired shift RPM is right -to light of weight and over rev- to heavy and slow to pull or cant pull the desired rpm.,dr spring for engagement with a reasonable rate and tune "play" with the secodary for back shift and no slip & cool clutches.Im a bit guilty of going with to staight of a helix. lol. Still learning
What Ive came across on my presant sled is it does not over rev so its hard (for me ) to know or figure out what is the right cam weight should be . as an example I went fron 68gr, which should have been to light, to 75gr weights of simalar profiles, All shifted at 7950-8000 rpm w/ same dr spring. back shift was bad w/75gr so went to 73.5 and tightened up sec and now its ok but still a little slow on the backshift. I think-beleive there is such a thing as to much belt preasure when it comes to the secodary. But how to know when is to much.??

spiderman thx for posting that link to teams spreadsheet. very interesting Im shocked at how little belt preasure was effected buy helix angle ??? It made no sence to me, great.:eek:

I look forward to hearing others means of clutching.:beer;

bstromer
01-08-2010, 09:21 AM
This is exactly what I was hoping for in this thread. Keep it up guys.


You are doing just fine XC

This is a great thread! Clutching seems to be most peoples weak point and will have the greatest performance impacts!

One thing to remember is to keep your clutch maintained with new parts and keep it clean.

snopro27
01-08-2010, 11:28 AM
AWESOME POST!! Im learning alot but i have one problem. I can get to 8000 rpms and hold it, but my belt and clutches are hotter then h*ll. any advice would be great!

Ron
01-08-2010, 02:10 PM
You need to provide a little more info about what you ride and elevation. One place to start is to start it with cold clutches run it hard and then stop to see which one is hottest. That's likely the place to start, the hot one indicates belt slip. If both are equally hot you aren't very close. Unfortunately R's are not "all there is to it". You can vary parts and still see little change in R's.
Edit: Oops lost my focus this is a thread on theory not to get into user issues, sorry!

furthur
01-08-2010, 05:39 PM
So how would you answer this question in theory. On the flats sled shifts out fast up to peak say 8000 rpm, but settles down to 7300 and will not gain from there. On a hill in the trees (on and off throttle) it will be responsive but will fade and eventually bog out. On a straight hill climb it will act like on the flats but will not hit peak in powder only in harder snow. Track speed is decnet on a hill, 40mph for only 7300 rpms. This is on an m7 by the way. Am I wrong in assuming that there is too much spring for the cam angle in the secondary not allowing it to fully shift out?
Another question being can you use a steeper cam angle to overcome a stiff spring?

Sounds like a stock M7 with the stock white spring...maybe 44/40 helix? You can compensate by adding preload to that white spring, but it will only be a bandaid for that trackspeed, and will limit your top end. The problem is no backshift. You have too much helix, not enough secondary force at start of shift, too much at the end, and a secondary with a tendancy to bind due to friction. Try a shift assist to help backshift, an AC orange, or better yet goodwin blue, if you can find it, with a straight 36-38 deg. helix. This will help your backshift with more force initially, without limiting upshift due to too much force at full shift.

Decent trackspeed at 7300 rpm tells you that 700 likes to be loaded hard. Keep doing that. You should, however, get it up closer to 77-7800. With the right secondary setup, you'll pull 45mph trackspeed.

John

lancelarue
01-08-2010, 08:20 PM
You need to provide a little more info about what you ride and elevation. One place to start is to start it with cold clutches run it hard and then stop to see which one is hottest. That's likely the place to start, the hot one indicates belt slip. If both are equally hot you aren't very close. Unfortunately R's are not "all there is to it". You can vary parts and still see little change in R's.
Edit: Oops lost my focus this is a thread on theory not to get into user issues, sorry!

Gear for your speed you run at. ( this is assuming you want a goodclimbing sled)

Clutch secondary to the load you're pulling.( track weight,size,rider weight, SNOW CONDITIONS etc.)

Clutch primary for target rpm / and to match secondary. Belt spinning in primary - raise finish on spring, add weight. Belt spinning in secondary - drop end rate on spring, drop weight to get rpm.
It's all about "balance" between the clutches AFTER you gear AND find the correct helix/spring to pull the load!!!!!!!!!

TIM
01-11-2010, 07:29 PM
what should one do. the sled goes up to the desired rpm and then steadly loses rpms. Basically the sled goes to 8200 rpms than settle down around 7600 rpms.

Should i got to a shallower helix?

astro
01-11-2010, 08:06 PM
Let's talk clutches. What are the pros and cons of the 2 designs of primary. TRA vs Pol/Cat/Yami

lancelarue
01-13-2010, 06:16 PM
what should one do. the sled goes up to the desired rpm and then steadly loses rpms. Basically the sled goes to 8200 rpms than settle down around 7600 rpms.

Should i got to a shallower helix?

Sled?
Rider weight ?
gearing?
track size?
Altitude?
Current set-up?
A few questions to start !

devilrmk
01-13-2010, 08:04 PM
None of that matters when we are talking about theory.

bigjb
01-13-2010, 08:28 PM
Sounds like a stock M7 with the stock white spring...maybe 44/40 helix? You can compensate by adding preload to that white spring, but it will only be a bandaid for that trackspeed, and will limit your top end. The problem is no backshift. You have too much helix, not enough secondary force at start of shift, too much at the end, and a secondary with a tendancy to bind due to friction. Try a shift assist to help backshift, an AC orange, or better yet goodwin blue, if you can find it, with a straight 36-38 deg. helix. This will help your backshift with more force initially, without limiting upshift due to too much force at full shift.

Decent trackspeed at 7300 rpm tells you that 700 likes to be loaded hard. Keep doing that. You should, however, get it up closer to 77-7800. With the right secondary setup, you'll pull 45mph trackspeed.

John

Yes m7 with rkt head and slp twins, lookin for 8100rpm but can't get it. Secondary has staright 36 and a team black orange 180/280 and shifit assist. Primary was set up with a slp black pink 120/340 spring and 66g dakota weights which have a steeper profile. My theory is that the shallow helix and stiff secondary spring under the slightest load could not upshift fast enough to keep up with the different profile weights. Without a load on the track I can get up around 7800 sometimes 8000 and it rips there but as soon as the track gets loaded rpms drop fast and get alot of belt heat, I can smell it pretty quick. So now I have cutler adjustables to put in and am loading up a 10.4 to put in the secondary set up with a new style 36 and cat orange with shift assist. Hope I'm working in the right direction.

Barrett
01-13-2010, 08:29 PM
what should one do. the sled goes up to the desired rpm and then steadly loses rpms. Basically the sled goes to 8200 rpms than settle down around 7600 rpms.

Should i got to a shallower helix?
I would first check to see if the clutches are hot which would indicate slippage. then:
if they are nice and cool(meaning no slippage problem), I would lighten the tips of the flyweights about 1.5-2grams.
if clutches hot (meaning slippage - its obviously slipping where the revs are higher)I would install a sec spring with stiffer start ,and re-test to see where rpms end up. you will likely need to adjust flyweights to correct running revs, but you willneed to test test test.:)
my .02

440dart
01-13-2010, 09:52 PM
iam very new to the clutching game. the biggest problem i have is understanding what effects what. lets say my helix is a 64-40-.46 "i like to refer the helix as like a manual trans in a car"

iam running the above helix mentioned with a lighter spring then stock i was going the wrong way with my clutching last year. this year iam going to try a 58-38-.36 with a stiffer spring but i had a guy recomend to try a 58-38-.36 what iam i gaining by going from a .46 to a .36 iam thinking by going to the .36 it will shift up faster and backshift faster if thats the case why dont more people go with a .36 instead of .46

shortstop20
01-13-2010, 11:21 PM
You are definitely using too steep of a helix with your setup(700cc, twin pipes, 174"). I wouldn't be suprised if you ended up using a 54-38 or something like that. Can't hurt to try that 58 first though.

RockyMtn.Kris
01-13-2010, 11:36 PM
iam very new to the clutching game. the biggest problem i have is understanding what effects what. lets say my helix is a 64-40-.46 "i like to refer the helix as like a manual trans in a car"

iam running the above helix mentioned with a lighter spring then stock i was going the wrong way with my clutching last year. this year iam going to try a 58-38-.36 with a stiffer spring but i had a guy recomend to try a 58-38-.36 what iam i gaining by going from a .46 to a .36 iam thinking by going to the .36 it will shift up faster and backshift faster if thats the case why dont more people go with a .36 instead of .46



The .36 or .46 refers the the distance in inches of the first angle. So the .36 will shift through the 58* angle and into the 36* sooner than the .46

440dart
01-13-2010, 11:38 PM
yeah i cant wait to try it out, i was so bass aackwards last year it still held its own pretty good. going to have clutches alighed this year also i remember my secondary getting fairly hot almost to hot to touch even with venting so i should have lots to gain

440dart
01-14-2010, 09:42 AM
but wouldnt also running the .36 back shift faster???

ruffryder
01-14-2010, 09:53 AM
mods, can this get cleaned up for theory only?

440dart
01-14-2010, 10:00 AM
as for this thread for the dummies like me maybe somebody can make a list of some sort exsplaining what each thing does and how it affects the sled and maybe make it a sticky. for the longest time i had guys tell me this and to run that but i had no idea why i couldnt find anybody to take the time to go through the secondary numbers with me. if somebody makes list as a sticky list some common problems that guys ask on here. example sled go's to 8000 rpm but on a long hill power slowly falls off to around 7800 you need to do this, this and this ect. not the best with words maybe iam confuseing some. but this would save alot of clutching questions on snowest. make it a sticky in every section,xp,m-series,iq,iqr ect ect

ruffryder
01-14-2010, 10:03 AM
as for this thread for the dummies like me maybe somebody can make a list of some sort exsplaining what each thing does and how it affects the sled and maybe make it a sticky.
It is a sticky, and it does try and explain what each thing does. You just have to read it from the beginning. ;)

Very valid point though, and good reasoning for cleaning this thread up.

440dart
01-14-2010, 10:06 AM
mods, can this get cleaned up for theory only?




i think .46 to .36 is a valuble question, i was just useing my sled as an example. i still think somebody should gather this imformation put on one page instead of scattered thru 3 or 4 pages once this "theory" page is ending

440dart
01-14-2010, 10:09 AM
It is a sticky, and it does try and explain what each thing does. You just have to read it from the beginning. ;)

Very valid point though, and good reasoning for cleaning this thread up.




haha i know i read through it some people i tried to understand just not that smart:( keep checking every other minute to see if somebody posted anything thing new starting to like this clutching stuff

ruffryder
01-14-2010, 10:09 AM
i think .46 to .36 is a valuble question, i was just useing my sled as an example. i still think somebody should gather this imformation put on one page instead of scattered thru 3 or 4 pages once this "theory" page is ending
Agreed, it is a valuable question, sorry, I wasn't trying to single you out, just noticed the thread direction has changed since the beginning. Again, not trying to single you out, timing is all. I happened to be looking through it and you were the last person that posted.

Not trying to be a dick, but I come off like that sometimes..

Thunder101
01-14-2010, 11:27 AM
Its hard to stick with theoy with out using examples,
So when it comes to the secondary things get alittle harder due to the fact
from brand to brand they vary in how they work, the winding of the spring vs some of the new ones that just use compression.
I found the link spiderman posted that showed the lb of force on the belt from the secondary with diff springs and helix's very odd. it did not go up in lb of force with the flatter angles like I thought it would. So here is the question, I understand you can have to much grip "force" in the secondary but what do you do when you are not getting GOOD back shift. ??? just dropping cam weight makes sence but at the same time that will effect the speed of your shift, even taking weight from the tip of the cam will help but not enough, So whats the theory on "tuning" a perfect shift someone must has a bit of a step by step tuning the clutches. Myself Ive always enjoyed and have had good luck with clutching many machines until this one right now has me guessing. Im under the belief the CVT it the perfect clutch but when your having a hard time getting close to perfect,,,,,,,,, I will watch for someone to post some knowledgeable tuning help. IMO clutching for drags is easy, clutching for top speed is not trying to get the best of both worlds is even harder.:D

440dart
01-14-2010, 07:52 PM
this died off fast

Spiderman
01-14-2010, 09:19 PM
How much spring force on the start and finish of the secondary spring does 1 delrin washer add? Does that number double and triple when you add 2 or 3 delrin washers respectively? I assume its minimal, but might change some when you have 2 or 3 in there?

RockyMtn.Kris
01-15-2010, 12:12 AM
The best way to get a fundamental understanding of clutching is to read Olav Aaens Clutch Tuning Handbook. Then read it again, then read it again.

One of the most basic things to understand about clutching is the primary is rpm sensing whereas the secondary is torque sensing.

Generally speaking the primary will shift based on rpm where the secondary will shift based on load at the track.


On the Derlin washers adding washers will add preload because you are compressing the spring but the finish rate wont change.

Thunder 101 on the backshift focus on the secondary not the primary. The idea is balance between the spring rate and helix angle. Too much side force it wont upshift, too little it wont back shift. As far as the "perfect shift" it doesnt exist because conditions and variables are not constant. The best we can hope for is a combo that works well in a range of conditions that match your riding style


Dart on the .36 shifting faster then the .46; All this means is that the secondary will be in the first angle a 10th of an inch less. It will shift into the second angle a 10th of an inch sooner. Its likely that it would slow the upshift to a marginal degree, but thats not necessarily a bad thing. You are trying to match the side pressure requirements of the belt for upshift and bachshift. You will probably not even notice the difference on the upshift but by doing this change it will probably help in loaded/deep snow conditions. Specifically when you let off the gas and get right back into it you will be in the shallower angle of the helix sooner or the 10th of an inch difference may be enough to keep it out of the steeper angle all together (in this example.)
I know this isnt the best explanation, but I hope it makes sense

shortstop20
01-15-2010, 10:26 AM
Good points by Rocky.Mtn.Kris.

Its hard to stick with theoy with out using examples,
So when it comes to the secondary things get alittle harder due to the fact
from brand to brand they vary in how they work, the winding of the spring vs some of the new ones that just use compression.
I found the link spiderman posted that showed the lb of force on the belt from the secondary with diff springs and helix's very odd. it did not go up in lb of force with the flatter angles like I thought it would. So here is the question, I understand you can have to much grip "force" in the secondary but what do you do when you are not getting GOOD back shift. ??? just dropping cam weight makes sence but at the same time that will effect the speed of your shift, even taking weight from the tip of the cam will help but not enough, So whats the theory on "tuning" a perfect shift someone must has a bit of a step by step tuning the clutches. Myself Ive always enjoyed and have had good luck with clutching many machines until this one right now has me guessing. Im under the belief the CVT it the perfect clutch but when your having a hard time getting close to perfect,,,,,,,,, I will watch for someone to post some knowledgeable tuning help. IMO clutching for drags is easy, clutching for top speed is not trying to get the best of both worlds is even harder.:D

IMO, and many others(but not all), you should tune the RPM with the primary and the shift with the secondary, as a rule of thumb, not an absolute. There are always exceptions.

How much spring force on the start and finish of the secondary spring does 1 delrin washer add? Does that number double and triple when you add 2 or 3 delrin washers respectively? I assume its minimal, but might change some when you have 2 or 3 in there?

The depth of the delrin washers is so small I would be very surprised if it makes any noticeable difference on spring rate. I bet the manufacturing tolerances aren't even within the depth of 3 delrin washers.

Thunder101
01-18-2010, 04:30 PM
Whats the theory on the sec spring, for back shift do you want a medium spring and "crank" it up tight or a stiff spring. I always worry that a stiff spring will have to much belt queeze towards shift out ? traditional cat secondary
Once over 100mph things start getting harder.:D
Im trying to get dialed in, its fast in 660, 1000 and in 2000' it starts to hit a wall unless thats all Im going to do,,,,, but I want to ride it as a regular ride and Im struggling trying to get a back shift.

onlyridesrmks
01-21-2010, 09:59 PM
Can someone explain to me why on a drive clutch spring, the manufacturer will say for higher peak RPM, increase the 1.25 compression rate, to lower peak rpm, decrease it. So if you increase it, then it's stiffer right? then won't it take more weight to overcome that heavy spring at the same rpm for full shift out? or more rpm with the same weight? well if i'm running 8100 and I need to get to 8300 won't a stiffer spring just keep the primary from full shift out? if I needed to get to 8300 and the belt is still 1/2 inch from the top of the primary then won't a spring with a little lower 1.25 compression rate allow the weights to swing all the way out?

PowerJoe
01-23-2010, 04:18 PM
Some basic questions...

Let's say there are two sleds that are identical except for clutching changes and one can get to 42mph and the other only to 36mph. Both hitting the same peak RPM. The first thought is that the one at 36mph is not shifing out all the way, correct? Is it possible that both of them ARE shifting out the same amount, but the one at 36mph is just slipping the belt that much more?

Are there any other factors I am not considering?

Why don't more people focus on track speed? Out of 100 posts I read on clutch setups, maybe 5 talk about track speed. Wouldn't high track speed be your number one goal and then maybe back shifting. I guess I am assuming everyone on this site rides in powder.

devilrmk
01-24-2010, 12:19 AM
Joe, I would say yes to both of your first questions.

I think the most efficient clutches = the most track speed. I think most of us try to optimize our clutching to get the effieciency which in turn creates that high track speed.

If your belt and clutches stay cool you have efficient clutching

astro
01-29-2010, 07:27 PM
Clutch alignment question. I've figured out that my jackshaft flexes enough for the secondary to move about .250" forward under full load. What's the theory on how to line up the clutches while planning for that kind of deflection? Standard 1" jackshaft with a .200" spacer between the bearing and the clutch.

winter brew
01-31-2010, 06:27 PM
Clutch alignment question. I've figured out that my jackshaft flexes enough for the secondary to move about .250" forward under full load. What's the theory on how to line up the clutches while planning for that kind of deflection? Standard 1" jackshaft with a .200" spacer between the bearing and the clutch.

I have never heard of a jackshaft flexing....at least not a measurable amount, yet 1/4"!! That's huge and something is seriously wrong if that's the case. Everything related to the jackshaft should be solid.
The engine does move alot though.
I do alignment the same on any sled with any combination of clutches. The belt should just kiss the inner sheave on the primary with all belt-sheave clearance to the outer sheave and no visible "dogleg" in the belt. C-C set for belt length and belt just above the secondary sheaves.

astro
01-31-2010, 10:25 PM
I have never heard of a jackshaft flexing....at least not a measurable amount, yet 1/4"!! That's huge and something is seriously wrong if that's the case. Everything related to the jackshaft should be solid.
The engine does move alot though.
I do alignment the same on any sled with any combination of clutches. The belt should just kiss the inner sheave on the primary with all belt-sheave clearance to the outer sheave and no visible "dogleg" in the belt. C-C set for belt length and belt just above the secondary sheaves.


I think you are right about the motor moving. I got 7 motor mounts so I wasn't expecting it to move quite that much. My jackshaft is supported by dual bearings on the clutch end. The actual motion is the Primary moves about .250" back and towards the chassis about .150"

You are talking at rest right? So you are saying with the belt starting against the inner sheave where it bends around the primary, it's just touching the surface as it passes the face?

Would this give me the best alignment at full shift out? My clutches run cool until they shift out. All the heat seems to be generated by the secondary. I initially let the secondary float to find the alignment point(not under full load). Then under normal riding it was hot. Put in a .100" shim and it was noticeably cooler.

winter brew
01-31-2010, 11:16 PM
Yes....at rest. Keeping engine movement to a minimum will keep alignment closer towards full shift. I suppose a guy could align differently to be closer to perfect at full shift if he knows how much things are moving....but are they STAYING at that location or just moving that much momuntarily under load??
Heat generated at higher shift ratio's in the secondary....let me guess, a TEAM clutch??

astro
02-01-2010, 11:38 AM
Yes....at rest. Keeping engine movement to a minimum will keep alignment closer towards full shift. I suppose a guy could align differently to be closer to perfect at full shift if he knows how much things are moving....but are they STAYING at that location or just moving that much momuntarily under load??
Heat generated at higher shift ratio's in the secondary....let me guess, a TEAM clutch??


Nope, a Paragon actually. Just added a 4 post Polar to the mix

hivoltagesledhead
02-08-2010, 03:02 AM
Getting a turbo to be "snappy" out of the hole is difficult, I've been told.
Can this be done with clutching so as to maintain the hole shot until the turbo spools up?

devilrmk
02-08-2010, 07:18 AM
Negative angled helix will help. Custom ground weights helps some too.

astro
02-08-2010, 11:11 AM
Polar is making me some ramps to compensate for that. It seems to manifest itself by loading the motor to much in the first couple of seconds when you pin it. Usually a slow climb to operating RPM.

devilrmk
02-08-2010, 08:51 PM
I ground my own helix on mine. Works pretty good.

clutch man
04-04-2010, 06:04 PM
what should one do. the sled goes up to the desired rpm and then steadly loses rpms. Basically the sled goes to 8200 rpms than settle down around 7600 rpms.

Should i got to a shallower helix?

It is time to get this going again. alot has not been coverd in here and some thing that our a bit off.
The # 1 rule in clutching the driven for falling off rpms in a climb do not fix it with the spring if it is over 200 rs. From 8200 to 7600 the ramp if to steep at the end and or the gearing it to high, 2.15 for 155 track 2.25 for a 162/163 track and a 2.33 for a 174 track now that is just a starting point on gearing there is alot that will play in there (your weight,snow conditions, elavation ect) remember gearing is a big part of getting the clutching right for where you ride track size and how you ride.
The #2 rule never change the drive clutch to match the driven. The driven just reacts to the torque of the drive and the load on the track. ( if you dont get full rpm at first change the drive clutch set up ) (if you get full rpm and then fall off change the driven clutch set up)

thefullmonte
04-06-2010, 08:14 AM
Can someone explain to me why on a drive clutch spring, the manufacturer will say for higher peak RPM, increase the 1.25 compression rate, to lower peak rpm, decrease it. So if you increase it, then it's stiffer right? then won't it take more weight to overcome that heavy spring at the same rpm for full shift out? or more rpm with the same weight? well if i'm running 8100 and I need to get to 8300 won't a stiffer spring just keep the primary from full shift out? if I needed to get to 8300 and the belt is still 1/2 inch from the top of the primary then won't a spring with a little lower 1.25 compression rate allow the weights to swing all the way out?

Lets say your sled is turning 8000rpm, but you want it to turn 8200rpm. The 8000 rpm spring was a 140/330. So you change to a 140/340. Using the same weights the increased spring pressure will require (gain) more rpm to overcome that increased spring pressure. Everything else being correct, that would be the main reason to increase spring pressure.
You are correct in your thinking though. What you are describing are inadaquacies in current clutch and weight design. Standard weights (Polaris example) can easily fall short with increased spring pressure. They are limited by design. Although you may gain the rpm you are looking for you may not achieve full shift out.
The lower compression rate may also allow it to fully shift out, but you may fall short on peak rpm. Hence not making peak hp. It is a very delicate balance. This balance is often thrown off by todays modern high torque high hp motors.
Using Polaris primary clutch as an example. It exibits very poor belt squeeze at engagement. Not very noticable on a 440 or 600, but an 800 will slip that belt quite a bit. Which is why people go to an adjustable weight with more weight around the pivot. This provides more belt squeeze at engagement. Another option is to lower the initial spring rate for a smoother engagement. By doing this, a stock weight has less spring pressure to overcome and can give better belt squeeze, but it also lowers the rpm that you engage at.
Sorry, starting to babble. Another thing people do to offset this poor engagement performance is to bypass it altogether. This is why people are using the steeper initial angle helixes. This helix will upshift very quickly requiring little input from the primary. It works, but you all but sacrifice low gear by quickly shifting to where the primary is more efficient.
In a nut shell, spring pressure whether initial or finishing rate dictates the rpm needed to overcome that pressure by weights that are assumed to be correct for your application.
I hope that helped. :face-icon-small-con

clutch man
04-08-2010, 08:58 PM
Can someone explain to me why on a drive clutch spring, the manufacturer will say for higher peak RPM, increase the 1.25 compression rate, to lower peak rpm, decrease it. So if you increase it, then it's stiffer right? then won't it take more weight to overcome that heavy spring at the same rpm for full shift out? or more rpm with the same weight? well if I'm running 8100 and I need to get to 8300 won't a stiffer spring just keep the primary from full shift out? if I needed to get to 8300 and the belt is still 1/2 inch from the top of the primary then won't a spring with a little lower 1.25 compression rate allow the weights to swing all the way out?

It is a mistake most people make when they our clutching, i have too it is cheaper to change the spring and not the cam arms, but is not the proper way to do it. When trying for more RPMS on the top change cam arms to a lighter cam arm. So if you our running a 68 gram cam arm at 8100 go to a 66 gram cam arm to get to 8300 in most newer higher torque motors now 2 grams up or down will get you about 200 RPMS up or down. Some fine tuning can be done with a the primary spring but should not be done to get more than 100 rs. you can put in a stiffer spring in the driven to get a few more rs too but not good to get more than 100 rs with a spring.

Norway
04-26-2010, 03:57 PM
Ok another Q for this one:

Spinning 9400 - 9600 with 150/340 spring and 62gr supertips, bearcat seondary with 54/44 and green snopro spring.

Want to get more umph at takeoff and possibly lower the max rpm a little.
Have a 165/310 primary spring. Any bets on the results?

Also, think I' possibly running out of gear and consider going up a tooth or two on the lower sprocket. Now, since the secondary is supposed to be load sensing it should gear down/hold a lower gear when there is much resistance.

This gearing up will increase resistance/torque feedback, but will it backshift faster/better or just stay in a little lower gear all the time?

RS

winter brew
04-30-2010, 09:08 AM
Ok another Q for this one:

Spinning 9400 - 9600 with 150/340 spring and 62gr supertips, bearcat seondary with 54/44 and green snopro spring.

Want to get more umph at takeoff and possibly lower the max rpm a little.
Have a 165/310 primary spring. Any bets on the results?

Also, think I' possibly running out of gear and consider going up a tooth or two on the lower sprocket. Now, since the secondary is supposed to be load sensing it should gear down/hold a lower gear when there is much resistance.

This gearing up will increase resistance/torque feedback, but will it backshift faster/better or just stay in a little lower gear all the time?

RS


Pure speculation here without knowing the sled, but IMO that green sec spring is pretty stiff for the amount of primary weight you are running and the helix angle....might try a softer sec spring and change nothing else.....or at least loosen that green as soft as it'll go. Ideally as little secondary spring as you can possibly get by with is ideal IMO.

Reeb
04-30-2010, 10:47 AM
Pure speculation here without knowing the sled, but IMO that green sec spring is pretty stiff for the amount of primary weight you are running and the helix angle....might try a softer sec spring and change nothing else.....or at least loosen that green as soft as it'll go. Ideally as little secondary spring as you can possibly get by with is ideal IMO.

I suggest something along the lines of a Cutler Red.

tdbaugha
09-14-2010, 08:59 PM
Also if there's anyone out there that can shed some more light on the Flyweight Profile, Mass Placement and the application of these concepts PLEASE SPEAK UP This is one area where I personally am just starting to understand in more depth and there are others here that are way more educated in this particular area and I would love to learn more as I'm sure others would as well.

Some areas that would be helpful in that discussion are how different mass placement effects shift profile for different applications. For instance Big Bore torque monsters seem to like more heal weight whereas turbos do not.

Lets keep this discussion moving and expand on things as much as possible, while making sure the basics are covered.


Heel and Tip weight is hard to explain. Think of turning a wrench, the further out you get from the pivot point, the more leverage you have. Heel weight(close to the pivot point) is more beneficial to the larger cc N/A motors because they have a fair amount of low RPM torque and horsepower. This low end power overcomes the heal weight. Tip weight(furthest from the pivot point) comes into play when you make a lot of peak power at high RPM. For instance, I talked to a guy from boondocker this weekend at haydays about clutching a turbo. They use a lot more tip weight because the turbo makes a lot of its power at the upper end of the RPM range. Did any of this make sense?

milehighassassin
09-27-2010, 06:56 AM
I un-stickied this thread to try and have less stickies. I will link it to the opening thread on top but I am hoping there will be enough discussion in here to keep this going.

pus1100
09-27-2010, 01:19 PM
Ok another Q for this one:

Spinning 9400 - 9600 with 150/340 spring and 62gr supertips, bearcat seondary with 54/44 and green snopro spring.

Want to get more umph at takeoff and possibly lower the max rpm a little.
Have a 165/310 primary spring. Any bets on the results?

Also, think I' possibly running out of gear and consider going up a tooth or two on the lower sprocket. Now, since the secondary is supposed to be load sensing it should gear down/hold a lower gear when there is much resistance.

This gearing up will increase resistance/torque feedback, but will it backshift faster/better or just stay in a little lower gear all the time?

RS

Rune,you can achieve this by moving washers on the supertips.take 2 washers from base and move to tip.increases rpm on takeoff and lower rpms on max rpm near full shift.supertips are great for fine tuning.how's that PFracing/ price combo spinning for you?

westech
10-02-2010, 02:43 AM
I posted the lower paragragh last season...struggled with clutching...ended up replacing the primary....had a bad roller on the spider...I thought it would solve alot of my grief but still seemed to loose rpm. Have some ideas thanks to this thread. Just looking for some input as I'm just starting to understand the basics of clutching. One thing I did notice though; I had been running the carlisle XS. I had a pretty worn out cat belt as a spare....what a difference it made! Was getting much better rpms(2-300) more. I could only make a couple climbs as the belt was loosing cords. Do belts really make that much difference? I should also note that on this ride which was the last ride of the season...I had cranked the secondary(RKT with 36/40 helix(I'll have to double check that) all the way and started to finaly see some back shift results. Also taken the primary from the 70 down to 68's. Seems like it may not be there yet...but I was finally starting to see improvement.


Went riding last week, things were good until I started pulling longer climbs. Noticed when the pull(rpm went down to 7000ish) got hard the engine seemed to go flat....not a bog but just not much there. Started trying to tune it out(It's an 05 with speedwerx pipe, y-pipe, mbrp can, sno-pro intake, RKT head and secondary and a boondocker box. Using an AEM air/fuel.) Found that at WOT it was good but if I let off in a climb and feathered mid to 3/4 throttle it stayed kinda flat. It's quite possibly not back shifting, but I did try to tighten up the RKT secondary, didn't change much. I'll try a stiffer primary (has 70g wieghts) with a yellow white spring.(I ran out of daylight) Elevation was around 5000ft. Tried adjusting fuel both ways....not much effect. Still learning to tune with the boondocker.I maybe don't understand the lo-mid-hi settings on the box...will have to do some more research. Anyway, not much there in the mid to upper unil WOT...when I would go wide open it engine would take a few seconds and then climb back up and run great. The engine tone would be different while lacking power too. Any thoughts? Never noticed this last year...since then came the y-pipe, sno-pro air, and RKT secondary. Also went from the 144 challenger extreme to the 153 powerclaw.

KSH
10-02-2010, 06:10 AM
I posted the lower paragragh last season...struggled with clutching...ended up replacing the primary....had a bad roller on the spider...I thought it would solve alot of my grief but still seemed to loose rpm. Have some ideas thanks to this thread. Just looking for some input as I'm just starting to understand the basics of clutching. One thing I did notice though;] I had been running the carlisle XS. I had a pretty worn out cat belt as a spare....what a difference it made! Was getting much better rpms(2-300) more. I could only make a couple climbs as the belt was loosing cords. Do belts really make that much difference? I should also note that on this ride which was the last ride of the season...I had cranked the secondary(RKT with 36/40 helix(I'll have to double check that) all the way and started to finaly see some back shift results. Also taken the primary from the 70 down to 68's. Seems like it may not be there yet...but I was finally starting to see improvement.


I will make a comment on the belts.
Besides the difference in compounds in the 046, 060 and Carlisle. And there is a couple hundred RPM difference between the 046 and 060.
The next time you go belt shopping take a ribbon tape measure and dial micrometer. You will be surprised how much variance in tolerances there is.

Just try to buy belts that are the same measurements that way you are keeping one part of the clutching equation the same.

milehighassassin
10-04-2010, 06:54 AM
I added the following to the first post:
I'm working on trying to consolidate some basic clutching info to post up just to give beginners a place to start. I've got a bunch of stuff down that should do such a thing, but was wanting to make sure it was all correct. Not only this but anything you could add would be great.

Namely something that I would like to get more info on is how the spring rates affect things. EX higher first number on drive spring = higher engagement, etc. Also how to fix slippage when using heat to determine which clutch is slipping more.

Anyways here is what I have. Let me know. Thanks!


Primary Springs
• Use to control engagement
• Higher numbers = stiffer spring
• Higher first number = higher engagement
• Higher numbers generally = more weight needed
• Too high last number = incomplete shift
• Too low last number = too quick shift


Primary Clutch
• Use to control RPM’s via weights
• Use to control engagement via spring
• If hotter than secondary belt slipping more in primary

Flyweights
• Use to control RPM’s – more weight = less RPM’s
• Heel (close to pin) weight affects beginning of shift (slow speeds)
• Toe weight affects end of shift (high speeds)
• More heel weight = better low speed (crawling)
• More toe weight = better high speed

Secondary Springs
• Use to control backshift
• Softer spring = more up-shift = more MPH
• Stiffer spring = better backshift
• Stiffer spring keeps clutch in “lower gear” longer


Secondary Clutch
• Is torque sensing
• Use to control Backshift
• Up shift = clutch opening =increasing speed = shifting up/out
• Backshift = clutch closing =decreasing speed = shifting down
• If hotter than primary belt slipping more in secondary

Helix
• Use to control upshift
• Shallower angle (smaller number) = faster upshift and slower backshift

thewayout84
10-06-2010, 12:05 PM
"
Helix
Use to control upshift
Shallower angle (smaller number) = faster upshift and slower backshift
"

isnt the other way, shallower angle= SLOWER upshift and better backshift?
steeper angle= more upshift but slower backshift. Thats why you need a stiffer secondary spring if you choose a steep helix and still wants some backshift left.

dgreet77
10-06-2010, 08:08 PM
"
Helix
Use to control upshift
Shallower angle (smaller number) = faster upshift and slower backshift
"

isnt the other way, shallower angle= SLOWER upshift and better backshift?
steeper angle= more upshift but slower backshift. Thats why you need a stiffer secondary spring if you choose a steep helix and still wants some backshift left.

Thanks for this; I'll go back and edit in the Clutching Basics thread, I had it that way then changed it. Sorry I suck at life. :focus:

KSH
10-19-2010, 07:31 PM
:bump2:

Dynamo^Joe
10-24-2010, 02:48 PM
Please tell us what you have learned about clutching. Asking questions about theory is OK also.

Keep posts about clutching THEORY not what one setup works with one sled.



Ok you asked for it. :face-icon-small-ton

What I see over the years is three short circuits that cause tuners to being reduced to parts-changers and eventually stumbling onto something that works until someone comes along and out performs them...then they are left in the position to start all over again with more parts trying to find an improvement.

1) Lacking knowledge of the law of how the clutch part works in the system. "Superstitious tuning" to where someone will say "this flyweight works with this helix", "this aggressive curve works with angles in this range", "can't use this spring here or there"
...and it keeps tuners from learning the law of how something works.

The law of how the clutch part works requires that the component exist in some tangible form.
The way the part works in the system can't just be a thought. The part has to be able to be measured and perform an operation that reveals factual data.
Now you have factual data, you'll be able to compile an adequate analysis "by measuring" for your own design or calibrating someone else design.

Laws
Flyweight mass determines steady-rpms at full throttle
Flyweight mass determines rpms at steady-part-throttle.
Flyweight determines rpm acceleration
Flyweight curve angle determines rpm acceleration (Comet type)
Ramp curve angle determines rpm acceleration (TRA)
Lever or flyweight Center of gravity distance from crankshaft center determines steady-rpms at full throttle (TRA)&(Comet type)
Lever or flyweight Center of gravity distance from crankshaft center determines rpm acceleration (TRA)&(Comet type)
Spring force determines steady-rpms at full throttle
Spring force determines determines rpm acceleration
Spring "Rate (angle of calculated line)" determines rpm acceleration.
Spring "Rate (angle of calculated line)" determines rpms at steady-part-throttle.
Helix angle determines steady-rpms at full throttle
Helix angle determines rpms at steady-part-throttle
Helix angle determines rpm acceleration
Helix angle determines belt clamp force at "X" sheave position
Final gear ratio determines steady-rpms at full throttle
Final gear ratio determines rpms at steady-part-throttle.
Final gear ratio determines rpm acceleration
Final gear ratio determines angle being used on the ramp (TRA)
Final gear ratio determines angle being used on the flyweight (Comet type)
Final gear ratio determines Lever or flyweight Center of gravity distance from crankshaft center
Final gear ratio determines Helix angle being used
Final gear ratio determines belt position in primary clutch
Final gear ratio determines belt position in secondary clutch

2) Misrepresentation of words communicating in clutching language. Misrepresentation of words and their conduct in a tuning question limits the ability to communicate an observation that can be analyzed. Misrepresentation keeps silent a fact by expressing a belief or a blind obedience to a tradition to which which is in fact not held true.

Example: Many people know my pet-peeve of the word "rate" when talking about springs; the word "force" or "forces" should be used. Force is something you can look at and measure at any instant in time. Rate is something you acutally have to sit down, measure and do some subtraction then division to calculate the "Rate" of a spring. A spring has "rate" in a system, compressed in a distance between two force values. Per inch.

Question – I weigh 230. Do I weigh 230 pressure or do I weigh 230 lbs?
Spring FORCE....force, force not pressure.........230 lbs force! 160 lbs force. 320 lbs force.
I don't weigh 230 pressure. A spring does not have 160 lbs start pressure nor does it have 320 lbs finish pressure.

I try to point tuners to a definition section
https://www.mxzx-revzone.com/article/language-111.asp
so we can all talk the same accurate language.

3) Lacking knowledge of how to measure the parts in the system while it works. (at full throttle) "Measuring" is just as easy to know and use to solve problems however a little bit more lengthy discussion.

Dynamo^Joe
10-24-2010, 02:55 PM
Ok another Q for this one:

Spinning 9400 - 9600 with 150/340 spring and 62gr supertips, bearcat seondary with 54/44 and green snopro spring.

Want to get more umph at takeoff and possibly lower the max rpm a little.
Have a 165/310 primary spring. Any bets on the results?

RS

Law
Lever or flyweight Center of gravity distance from crankshaft center determines rpm acceleration (TRA)&(Comet type)

Does the flyweight have composite materials to move around? (nuts/bolts/setcrews)

Do not change the flyweight mass. Keep it at 62g. Take the center of gravity and move it towards the tip. Is there a washer you can take from position # 1 or #2 and move it towards position #3 at the tip?

Moving the center of gravity will allow the engagment to be about the same rpms however the engine will become more revvy in the bottom end/low clutch ratios (adjusts how quick engine rpms will accelerate)
The other feature this will reveal is the flyweight will start to push harder than with the previous center of gravity position. The center of gravity being farther away from the crankshaft centerline, the flyweight will push harder - and you did not have to change the grams.

thewayout84
11-09-2010, 01:18 PM
On gearing, the lower you are geared the less secondary side pressure is needed due to the decreased load on the secondary.



are you sure about this? if i gear down and puts a lighter spring in the secondary it would upshift even faster, right?
when the secondary seeing less load from the track with a gear down it would upshift faster than before and drop the rpms down.
the right thing to do is go with a stiffer finish rate on the secondary spring or less helix angle.
I dont really understand why people say go with lighter weights or higher finish rate on primary spring, how would the secondary react to that if its already shifting out faster then before? can someone explain that to me:)

thewayout84
11-29-2010, 03:34 PM
someone plz???

Ove
12-18-2011, 07:09 AM
"
Helix
Use to control upshift
Shallower angle (smaller number) = faster upshift and slower backshift
"

isnt the other way, shallower angle= SLOWER upshift and better backshift?
steeper angle= more upshift but slower backshift. Thats why you need a stiffer secondary spring if you choose a steep helix and still wants some backshift left.
Thanks for this; I'll go back and edit in the Clutching Basics thread, I had it that way then changed it. Sorry I suck at life.


Really, but when the combination is done. The steeper helix that need a stiffer spring to work and lighter weights to work. This is what makes most backshift at the end of the day.

A shallow helix backshift better at lunchtime but would overrev, then add primaryweights to get revs down and at the end of the day this has least backshift.

heavy weights/shallow helix = Least backshift

Lightweights/steep helix = most backshift

With the 2ndary springs needed with the helixes to keep tumbs from frying on the sheave.

Anthony Reister
02-14-2012, 01:38 PM
Is there a formula to figure out what your clutch ratio would be? I know how to figure out gear ratios, but the clutch ratio? I'm running a 19-43 gearing(2.26ratio), track is a 162-2"- 3.0 pitch- 8 tooth drivers running about 150 to 160 hp the helix in the secondary clutch is a 36 degree with a red spring for 3000 to 6000ft.