I was looking at the belt sizes for the UR crank pulley on their web site. And comparing them to the stock sizes, and I realized that the belts they call for are smaller than the stock ones. Smaller belts=smaller diamer pulley. Why would this be, if the pulley is underdriving (thus should be slightly bigger). Anyone installed theirs and know the answer? Were the belts smaller?

 

I found an old post under the TL forum that confirms that the UR pulley is smaller. But i still ask, how would a smaller pulley achieve an underdriving effect?

 

https://acurazine.com/forums/showthread.php?t=183908

?

There is plenty of info out there.

www.unorthodoxracing.com

ask Excelerate.

 

I have looked through most posts i could find on the subject via search. None of them addresses my question.

 

The belt is smaller. The underdrive crank pulley is smaller. The belt has to accomodate for the smaller size of the crank.

Me and a lot of other people have the underdrive cranks installed.

The belt will NOT be bigger for a smaller pulley.

 

I looked through UR's faq section, and the underdrive pulley is supposed to be smaller. So that is correct.

 

The underdrive pulley is slightly smaller in diameter and slightly underdrives the accessories.

 

Yeah that would make sense. Why the hell did I think before the pulley was slightly larger?

<---- Moron at times.

 

Don't worry, I'm dumb right there with ya. I thought the same thing, but it only makes sense if its not a driven pulley, but one that is being driven. Then it could be bigger.

 

you need Gates K060441 and Gates K040425

I'm looking at the paper right now. Some of the links when I searched had the incorrect belt size for one of the two.