Track speed gearing and clutching debate.

WyoBoy1000 said:

LOL. I did all the math once and came up with 8" as a 1:1, but that was measuring the outside of the belt and saying the outside of the belt would be sitting at the 8" point and then going inward. So the inside of the belt may very well be at the 7.3" diameter. ???

This is where I go back to "there is to many variables"

Something else I was thinking of that kinda makes sense.

When you figure track speed lets say you figure it for the speed at the drivers- like we where figuring speed, but from are math above what if these turbo's , with there "big track speed" that they are more likely to plain out and might be running more on the tips of the track where as the NA sleds are digging and running on the bottom of the lugs rather than on the tips like the turbo. So even if you go 1/2" further out on the lugs puts you a full 1" larger diameter which makes for some serious speed increases. Kinda makes sense.

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I used to wonder about that too. Then I visualized a track laid out on the ground. It really doesnt matter how long the track is or how tall the paddles are, the drivers contact the lugs 1 for 1, so the track speed does not change based on how far away the lug contacts.

The track speed is measured of of the drive shaft. It is what is.....as long as there is no track ratcheting and the speedo is actually accurate.

Now ground speed is certainly different as we all know.

Hope this helps.

If you go from a 1" track up to a 2" track it gears your sled up
If you go from a 2" track to a 3" track it gears your sled up

If you wear the tires down on your pickup you are gearing it down

Think of your track as one big tire, hard to visualize, but that's the effect.

speedometer registered numbers are for your driveshaft rpm, only an estimate of ground speed on a sled. 10" lug tracks gear your sled up will create more ground speed while showing the same drive shaft rpm / speedometer. Ask any heavy equipment cat operator that put new undercarriage on his cat.

Usually I dont jump in on these, but the group I ride with have come across some interesting observations regarding this. most of us ride 1200 turbos on 162.

ALL of the items are relavent to track speed and performance, this could be long since I keep going back and forth on which track to run.
1. snow condition
2. type of track
3. gearing
4. Clutching

Im probably making more power then the rest of the guys but we found that on good snow condition days the guys with the powerclaws climb farther and have less track speed. On harder days on my extreme I do, I can gear up to make the track spin faster on soft snow days and still cant climb as easy. But by gearing up I create belt heat which means slipping so gearing does have a relationship to track speed, you need to find out what your climbing speed is and gear for a 1 to1 ratio. If you are under 1 t 1 you are wasting valuable power through belt heat.
So back to track speed, it is an item to use for assessing what works for you. But track type, snow condition, clutching and gearing all have a relationship to it.
Since the sled Im on has a extreme track that works better for harder conditions then a power claw, Ive set the sled up for that condition and give up some performance on the powder days. If I had a spare power claw I would have it on right now and readjust everything including clutching and gearing for the optimum climbing speed.

one last thought on gearing if it wasnt important, most AC sleds are geared around 60/60 if it wasnt important why not do a trail sled gearing of say 70/50? Its important to pick the correct gearing for your design to make it run properly. Example is the amount of traction that your sled gets, Powerclaw vs. extreme do not get the same traction since there designed to work differently. thoughts?

WyoBoy1000 said:

Well thats would make sense but a track is not a tire and when the track is running flat the bottom and the top of the lug 0-2" of height are moving at the same speed, the only place the tips speed up is as it goes around the wheel, then it has to go faster but matches speed again on the flat. Think of this if the tips where going faster when on flat ground they would be trying to out run the track itself.

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True. The tips of the paddles will only go faster than the inside of the track when they are moving around the wheels and drivers. Any flat surface of the track will be moving at a uniform speed from track to paddle tip.

WyoBoy1000 said:

SnowDevil,
I agree with what you have said and never really disagreed, But the one thing I don't agree with is you say you can gain speed but loose it in the clutching, To me that can be fixed with clutching, granted there is a point that the gears need to be within a certain range, I don't argue the fact that 70/50 gears would be a stretch.

But AC gears all the sleds to have about the same top speed, the sleds that rev higher rpms have lower gears. Its a gear set that works in all conditions but may not be the perfect match.

More than anything I argue that a person can see better results with the right clutching over changing gears and since no one has perfected clutching or always finding something better I think it would be a bigger advantage to focus on clutching over gearing. In all honesty if I can get 5mph more track speed but go through more belts, I will go through more belts.
But I have stock gears and only running 6lbs of boost at 9-10000ft and I can make some hard pulls and even get in and out of the throttle, more or less try and heat up the clutching and then immediately touch my clutches, ie leave my bare hand on the clutch sheaves.

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Well Im going to disagree, I am not willing to go through more belts for 5mph, last thing I need on a crazy climb is over heating the belt and blowing it!
My sled is built to go fast and stay together, if your going to spend 7k on a turbo some gearing a clutching parts go with the territory to make things work
When you say Arctic Cat gears the sleds depending on rpm your correct! for a stock sled we are not talking about stock sleds here.

Higher gears = more speed = more heat, I use these on race day and plan on going through a belt or 2. not doing any crazy climbs on this setup or tree riding. plus a clutch change is needed

Lower gears = little slower top = cooler belt, ride this most every day, can go 6-8 rides on one belt. much more fun to ride and the sled will still scare the crap out of 99% the people who ride it.
This setup makes the most sense, I have appx. 3x's the hp of stock and I have geared the sled down. everytime I have geared the sled down I have found that the belt gets better traction on multipule pulls (day riding). I dont have to switch belts for traction like race day or burn my hands on the belt (done that one!).
Ive spent a couple years going through clutching and gearing, clutching is locked in as good as it can with the hp. adjusted the gearing to the type of riding and snow condition if I feel like it.

These are just adjustements I have found that work, but to say gearing isnt important doesnt make sense. Unless you like giving AC money for belts.

gearing will help correct clutching temp problems in relationship to traction and hp.

mynewuseddoo said:

Excelent thread! I have been wondering the same from other turbo riders also.

7000 feet
9 psi boost
CPC stage 2
50/50 av/premium
2009 M8 162
powerclaw
gearing 57/63 (stock).....for now
8000 RPM
12.3-12.5 AFR
CPC secondary w/green spring set at 5
Primary, CPC gold spring and 80-90 gram turbo mags at 86 grams.

In a fresh, steep and deep climb 46-50 mph. Climbing the same grade in a harder packed snow I can see as high as 55-57 mph.

Thank you for the honesty from everybody. Before I bought the turbo I would always hear stuff like "a solid 60 mph in a deep climb", from guys running pump gas kits at lower boost than I am running. With seeing my track speeds in the deep snow climbs only hitting 46-50 mph and running higher boost than them had me thinking something might be wrong or my clutching was off.

I am lowering my gearing to 54/66 to hopefully gain a little more from the really deep heavy snow climbs and pick up the track speed into the mid 50's. I'd like to see 55 mph in a deep climb at 9 psi boost.

Or I could just turn the boost up I suppose

I will report back after I get to ride the new gear set and see the difference.(Mid February)

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Installed the new 55/65 gears, in a steep and deep climb with the powerclaw track 54-57 MPH, in harder pack I would see about 60 MPH. My previous track speeds are in the quote above. The lower gears are seeming to work pretty good. I find them much better for boondocking too.

The gears are the only thing I have changed, going from 57/63 to 55/65. I will be installing the 9175 camo extreme this week.