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850 clutching

kanedog

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If my memory serves me correctly in order to run in 1:1(full shift) hillclimbing your sled would have to be geared for a top speed of roughly 45 MPH. I can't find my clutching efficiency breakdown but I believe the difference in efficiency between 2:1 and 1:1 was negligible like 1 or 2%.
A sled can be geared for 50 mph and it will go 50. Where as presently, most sleds are geared for 75mph but only do 30-40mph in a 5mph ground speed hillclimb. This puts the belt at halfway up the primary clutch sheave which is gay, lazy, poor backshift, inconsistent rpm and rpm will fade on the top end.
Most clutchers haven't chased this issue down far enough. They settle for close to perfect instead of perfect.
What happens is tuners get to about a 2.7 gear ratio(gr) and it doesn't make much of a difference and they give up and go back to antiquated clutching techniques(2.2-2.5 ratios). They actually needed to keep gearing down but nothing is available off the shelf so they give up. They need to go to at least 3.2gr and higher(165" 3"). This ratio is where the magic starts to happen. As far as I know, I have the lowest 174" gearing(3.48) in the while widest world and I can beat turbos.
Cheers and fawk the doubters. It's time to move clutching from the 80's to 2020.



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80, 82 and 84 tooth bottom gear for a belt drive. Modifying of chaincase may be required. Experiment!
0f9d4d0e7206f21be43bcd8963f476b0.jpg
 
Last edited:

revrider07

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This is a TRS thread if you are selling a different product or questions on someone else's clutch kit start your own thread.
 

kanedog

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This is a TRS thread if you are selling a different product or questions on someone else's clutch kit start your own thread.
I have nothing to sell, clutch wise or anything else and never will. Nor do I have questions on someone else's clutch kit. I like to share my knowledge and experience like a forum is meant for.
Sure, TRS started this thread. He should have answered the question on 1-1 clutch ratio but he didn't. So I did.
Carry on. I'll go read the first post and see what all this hubbub is all about. Cheers big ears!
Just read this thread and I have determined that Revrider has a crush on TRS. I'm partial to clutching guys too! No biggie. All good.




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Last edited:
D
Feb 2, 2017
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Afton, Wyoming
A sled can be geared for 50 mph and it will go 50. Where as presently, most sleds are geared for 75mph but only do 30-40mph in a 5mph ground speed hillclimb. This puts the belt at halfway up the primary clutch sheave which is gay, lazy, poor backshift, inconsistent rpm and rpm will fade on the top end.
Most clutchers haven't chased this issue down far enough. They settle for close to perfect instead of perfect.
What happens is tuners get to about a 2.7 gear ratio(gr) and it doesn't make much of a difference and they give up and go back to antiquated clutching techniques(2.2-2.5 ratios). They actually needed to keep gearing down but nothing is available off the shelf so they give up. They need to go to at least 3.2gr and higher(165" 3"). This ratio is where the magic starts to happen. As far as I know, I have the lowest 174" gearing(3.48) in the while widest world and I can beat turbos.
Cheers and fawk the doubters. It's time to move clutching from the 80's to 2020.



Sent from my SM-G920W8 using Tapatalk
80, 82 and 84 tooth bottom gear for a belt drive. Modifying of chaincase may be required. Experiment!
0f9d4d0e7206f21be43bcd8963f476b0.jpg

Would you mind sharing where you got those gears from
Thanks
 

revrider07

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I have nothing to sell, clutch wise or anything else and never will. Nor do I have questions on someone else's clutch kit. I like to share my knowledge and experience like a forum is meant for.
Sure, TRS started this thread. He should have answered the question on 1-1 clutch ratio but he didn't. So I did.
Carry on. I'll go read the first post and see what all this hubbub is all about. Cheers big ears!
Just read this thread and I have determined that Revrider has a crush on TRS. I'm partial to clutching guys too! No biggie. All good.




Sent from my SM-G920W8 using Tapatalk

So is it that hard to start your own thread on gearing or what? Im sure it works for you but it doesn't work for me. Derailing these threads and will lead to less sharing of info.
There is more than one way to skin a cat. Use what works for you.
 

kanedog

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Would you mind sharing where you got those gears from

Thanks
Pfeifer engineering. It's a bit of a process as it's a busy shop so these one offs kinda sit on the desk until there is a time slot open. Great knowledgeable guy named Jim. Great product.

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Last edited:

Tewstroke

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I guess I’ll have to go find my Aaen clutch book and re-read it.
I recall learning that a 1:1 ratio on the clutches was where the belt was riding at equal diameters on both clutches, NOT full shift out.
It is most efficient at equal diameters/equal height in the clutches because the belt is getting good gripping diameters on both clutches instead of going around a tight curve with less belt to sheave total contact on one clutch.
Is this correct?
 

TRS

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I guess I’ll have to go find my Aaen clutch book and re-read it.
I recall learning that a 1:1 ratio on the clutches was where the belt was riding at equal diameters on both clutches, NOT full shift out.
It is most efficient at equal diameters/equal height in the clutches because the belt is getting good gripping diameters on both clutches instead of going around a tight curve with less belt to sheave total contact on one clutch.
Is this correct?

Yes sir.
 
P
Jan 22, 2013
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Can you shed some light on this.... in a Full progressive helix your never are in the first and last angles. As soon as you move your out of the 42 angle and your never completely shifted out so you wont use the 32 angle. So, your suggesting that a 41-33 shift out with lighter weights is achieving better results?
Yes the Secondary spring is much lighter, (125-175) but the lighter weights and stock spring (120-320) wont allow more primary pull as you have gone backwards on effective primary shift out..
Em I missing something here?
It takes 2-3 grams of extra weight in the primary to generate enough force to open up a team secondary with 200 lbs of spring pressure. When you reduce the secondary spring pressure by 100 lbs, you can get away with less weight in the primary. The shallow helix, which is the torque-sensing component, is generated belt squeeze, not high fixed spring pressure.
 

Wheel House Motorsports

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Just did another side by side test this weekend.

2 2020 Khaos 850's with identical track etc.
1 with Kurts, one with TRS clutching. After running side by side. Both will have TRS clutching for next weekend. Tony's setup keeps shifting up whenever possible, standard 10 series weights stiff springs and steep helixes are OK feeling but stall out around 40-50mph and are unable to upshift unless on flat ground. That nice soft spring and shallow helix allow continued up shift instead of hitting a wall.
 

cdebodt44

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Are you running the TRS kit with a gear down?


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damx

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Never noticed that little x hiding there, now I must go check mine.
 

kanedog

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What is the top and bottom pulley sizes on the pro gears?
 
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