cvt belts

[gr race]

What affect does a shorter or longer belt have in the clutch

[drr5]

belt travel on the pullies we run the short on 50s and the longer on the 90s but the opinions vary

[wrhracing]

Shorter belt will generate more stall than Longer belt (Larger I.D. on the rear) With the same pullies, shimming, and clutch. -vs- engine RPM.
Longer belt offers more pulley travel, if it doesn't bind in the rear pulley due to width of the belt.

[BradLoomis]

Originally posted by wrhracing
Shorter belt will generate more stall than Longer belt (Larger I.D. on the rear) With the same pullies, shimming, and clutch. -vs- engine RPM.
Longer belt offers more pulley travel, if it doesn't bind in the rear pulley due to width of the belt.

I think Billy meant "lower" the stall speed, as the same width of belt with a shorter length would be the same position on the front variator, therefore would be deeper into the rear pulley because of the shorter length. Being deeper in the rear pulley, with the same depth in the front variator, would be like dropping from a larger rear sprocket to a smaller rear sprocket. That means that the same front sprocket rpm into the smaller rear will generate a faster top speed.
The length of the belt is as critical as the width is. The best belt width is the one you can get the deepest into the rear pulley (a limiting factor of movement) without binding like Billy stated. Then look at what length is needed to get around the open position of the front variator and the closed position of the rear pulley. Then the This is the right length belt for maximum travel of the cvt. Now to get full use of it, you must make sure the front variator rollers have enough travel to force the belt as deep as it can go into the rear pulley. The CVT is now setup for maximum travel before stall speeds and roller weights are figured out.

[wrhracing]

I don't know what I meant to say.
My computer skills suck. I meant to say that.
I'll try one more time.... My exagerated version is this,, if you had a set engine rpm , and say a very large diameter rear pulley, belt to match which is longer, with the clutch shoes working by centrificul force I think the speed at which the rear shoes are turning is lower than if you had a smaller rear diameter pulley, same engine rpm, and a shorter belt to match.

Kind of like a larger diameter tire turns more slowly at the center of the hub than a small trailer tire does.

Although in the context of the initial question, this gentleman may not notice the change ... but it is there.

[dcarter]

okay guys!!!
now i see why my son rides a 90 mod!!!!!!! thanks for the info do one of you guys want to come to the nationals and teach me this stuff!!!! dave

[gr race]

I,m really confused now??????

[wrhracing]

Here's another answer.

Shorter belt is stock on most CVT's. MOST, not all.
It has a lenth of 780, the most common longer belt is 788.
If the belt is longer it will give a slight increase of gear range, or a slight amount of top end over a shorter belt.
It is only 8mm not something I would consider a major difference.
Having a new fresh belt on is a far better thing to do, than using a older belt that has wear on it and has diminished in width because of wear.
I apoligize for getting off subject.

[gr race]

THANK-YOU Billy much better

[tireman43]

Randy you gonna be ready in a few weeks for Staples? How's Remmy's rocket ship coming along? Good luck on the belt thing. See you at the track. Sorry it's a little off topic.

Kevin

[gr race]

Kevin right now i feel like i will never be ready but what do you do see you at the races Randy