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Tell me about sheave rollers

6958 Views 20 Replies 12 Participants Last post by  azcourt
Ok, I have read all of the threads on RF.net and they are too technical for me. I don't really care for the breakdown of how a CVT works. What I want to know, in simple, very simple terms, is what gram does what.

If I use lighter rollers do I have less top end, but get there faster?
Or is it heavier rollers?

I have a CDI, Sheave, and K&N. I can go 59 right now. I would like to go 50, but get there fast. I need some good usable torque for the dunes. How about it? What rollers do what to the clutch?
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I believe lighter weights will get you less top end but better low end torque...but I may be wrong.... Im sure someone will chime in on this soon enough.
I believe lighter weights will get you less top end but better low end torque...but I may be wrong.... Im sure someone will chime in on this soon enough.
You are correct....

The lighter rollers will keep the RPM's lower and help you reach max power faster. Lighter rollers will reduce your top speed.

I tried lighter rollers and I didnt like them. I went with 14 gram and 12 grams. Then I mixed the 14 and 12 so I had 13 gram rollers. Great for the sand but not so good for the trails or desert rides.
Thanks Mikef. What did you end up with? You said not so good with the 14/12 mix. Can you elaborate? What did it feel like? Does it take longer to engage, or does it just stay lower longer? Thanks for your help


I forgot to add, I have 26" Terra Crosses. So should go with 14 gram all the way? I do 60-40 dunes/desert. Does anyone have experience with this type of setup?
Some friends of mine did some testing the other day and here is waht they found.

2 stock rhinos drag racing, one was 1-1/2 lengths beyond the other at 45 mph every time. Above 45mph the slower rhino became the faster one slowly passing with a 2mph higher top speed. The quicker off the line one went 55mph top speed, the faster overall was 57mph. Both have similar mods, sheaves ect.

Added a blue spring to the one getting beat to 45 and it gaines a half a length back in the drag race, no change in top end.

Added 14 gram weights and it picked up another 1/2 length. Changed to all 12 gram and it's 1/2 or more car ahead and picked up 2mph top speed. It now spins the tires like crazy taking off too.

Did the same mods to the other car and it is back to 1-1/2 lengths ahead again.

So in the end they decided thay love the blue spring and 12g weights, they ordered 4 more sets for thier friends.
Some friends of mine did some testing the other day and here is waht they found.

2 stock rhinos drag racing, one was 1-1/2 lengths beyond the other at 45 mph every time. Above 45mph the slower rhino became the faster one slowly passing with a 2mph higher top speed. The quicker off the line one went 55mph top speed, the faster overall was 57mph. Both have similar mods, sheaves ect.

Added a blue spring to the one getting beat to 45 and it gaines a half a length back in the drag race, no change in top end.

Added 14 gram weights and it picked up another 1/2 length. Changed to all 12 gram and it's 1/2 or more car ahead and picked up 2mph top speed. It now spins the tires like crazy taking off too.

Did the same mods to the other car and it is back to 1-1/2 lengths ahead again.

So in the end they decided thay love the blue spring and 12g weights, they ordered 4 more sets for thier friends.
Court do you sell this combo ? Im looking into a sheave and looking for the best combo, send me a pm with a price if you do. Thanks
Court do you sell this combo ? Im looking into a sheave and looking for the best combo, send me a pm with a price if you do. Thanks
I am not sure he does since his store closed, call Mike or Greg at Unleashed UTV and ask for that combo. I prefer the 14g's for trails and dunes with blue spring.

Rog
Some friends of mine did some testing the other day and here is waht they found.

2 stock rhinos drag racing, one was 1-1/2 lengths beyond the other at 45 mph every time. Above 45mph the slower rhino became the faster one slowly passing with a 2mph higher top speed. The quicker off the line one went 55mph top speed, the faster overall was 57mph. Both have similar mods, sheaves ect.

Added a blue spring to the one getting beat to 45 and it gaines a half a length back in the drag race, no change in top end.

Added 14 gram weights and it picked up another 1/2 length. Changed to all 12 gram and it's 1/2 or more car ahead and picked up 2mph top speed. It now spins the tires like crazy taking off too.

Did the same mods to the other car and it is back to 1-1/2 lengths ahead again.

So in the end they decided thay love the blue spring and 12g weights, they ordered 4 more sets for thier friends.
that would have been a cool test to do. sorry for the hi-jack:good:
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Stock rollers i believe are 16 gram. I went to 14 gram and a silver sping from ACI. I can tell you that my rhino stays in the power while climbing hills now.



Silver spring ? whats the difference from the blue ?......when you talk about these springs its the same as a duners kit right ? sorry starting to get confused.
The silver spring is the heaviest spring offered. On a compression scale it is 250 at 3 inches of compression. Its the same as the white EPI spring. The Blue spring I believe compresses at 180 pounds at 3 inches. I did notice last trip my top speed only seemed to be about 46 mph on the flats....But then again that was at pismo. I have been afraid to test it on the road



It is kinda hard to do a thread like this without getting into explanations of how a CVT works. The lighter rollers actually make your RPM's higher. Which is most likely what you want. The CVT was designed to keep the same RPM's while your speed increases. The RPM you want it to be at is whatever RPM your engine is most efficient at. The RPM that has the best HP/Torque. At this RPM you will accelerate faster. The springs are the most confusing part. A spring does multiple things on the secondary pulley. I stronger spring will help you back shift quicker, but will also give similar results as installing lighter roller. The stronger spring in the secondary will make it more difficult for the rollers in the primary to push outward. It will require more force. To get that force it will require more RPM's. A stronger spring could also lose efficiency. Too much force on the belt will cause more friction and dissipate power as heat. You could possibly lose top end as well. Hopefully I have done a thorough job of confusing everyone.
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Some friends of mine did some testing the other day and here is waht they found.

2 stock rhinos drag racing, one was 1-1/2 lengths beyond the other at 45 mph every time. Above 45mph the slower rhino became the faster one slowly passing with a 2mph higher top speed. The quicker off the line one went 55mph top speed, the faster overall was 57mph. Both have similar mods, sheaves ect.

Added a blue spring to the one getting beat to 45 and it gaines a half a length back in the drag race, no change in top end.

Added 14 gram weights and it picked up another 1/2 length. Changed to all 12 gram and it's 1/2 or more car ahead and picked up 2mph top speed. It now spins the tires like crazy taking off too.

Did the same mods to the other car and it is back to 1-1/2 lengths ahead again.

So in the end they decided thay love the blue spring and 12g weights, they ordered 4 more sets for thier friends.
Here's an update on the testing. We took 4 rhinos out yesterday morning to mile marker 12 & Carefree Highway. Karl's (26X12 bighorns) and mine (26X14 bighorns) have the blue spring with 12 gram rollers (full bed intact with coolers & tools), Brian's (25X12 terra cross) has the blue spring with 14 gram rollers (bed deleate) and Davey's (26X12 bighorns) has just a machined sheave (bed deleate). In the big washes Karl & I could get away a lot quicker coming out of the turns and straight line acceleration. What I was most impressed with was the hill climbs. With all of the tools I carry and the cooler I used to struggle on some of the steeper, longer climbs. Yesterday I had to get out of the gas a couple of times because it was pulling so hard. I'm very happy with the setup.

We do have a couple of other tests planned. Davey has a lathe and we're going to mill a set of stock rollers down to 11 grams each and a set to 10 grams each and mix them with the 12s to see what happens. We'll keep you posted.
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Thanks for the updates. Next week I am going to pick up some 12 gram rollers.

Does the spring interfere with the engine brake?
Thanks for the updates. Next week I am going to pick up some 12 gram rollers.

Does the spring interfere with the engine brake?
Nope it will not.

Rog
Eventually lower weights will make yoou lose top speed i'm told. Never seen it myself, but i've never gone lower than 12g.
Price,
Bring those rollers with you tonight and so I can get them to Batman.
I have a KMS sheave 12g rollers and a blue spring. The sheave shifts at 43 MPH and I top out at 58MPH. I have 26"(27") bighorns. It clibms great dunes great and works good on the trails. Here is a video that towards the end shows how the CVT works:
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