I have a 3.75 pulley and these 2 belts 4060380 AND 4060385 . I was told one is just going to fit tighter but I want to know which is the better one to use?

 

some recommend using the bigger belt and tightening the tensioner more.

 

https://www.s2ki.com/forums/index.php?showtopic=254159

 

yeah I have seen that link and there is NO 3.75....



For Comptech:
4060400 Standard AP1
4060395 4.25inch
4060390 4.0inch(7#)
4060385 3.5 3.35inch
4060380 3.25inch
4060370 3.0 inch


mine falls in the middle and I have both the belts in hand.

 

try it and see. it should just clear the sc pulley and then you can tighten the rest.

 

I am running a 385 with SOS's 3.6" pulley and it was a bit tight to get on. I had to "walk" it onto the pulley by getting it started then putting a wrench on the crank pulley and turning an inch or 2 to get the belt to travel. Once on and over the pulley lip, it fell in place and is a great fit.

I was having so much trouble getting it on at first, I went and bought a 390 but it was definitely too big. If I had to guess, I'd say with your larger pulley that you would probably need the 390. If you go on Dayco's web sight and dig around, you can find exact measurements. I bought the 390 thinking they were probably listed in mm and it would be just slightly larger but it turns out to be more than an inch bigger if I remember correctly.

Also, I'd rather have the smallest belt you can properly fit. Based on my experience, you'd never even be able to install a belt that was tight enough to not need the tensioner. I would think you'd want to be able to increase tension as needed with the tensioner, and have enough travel left for normal belt stretching over time. I can't see any benefit in a highly deflected belt right out of the box.

 

turns out the 80 was the way to go as the 85 was to loose on the pulley. Thanks guys for all your help and input. This was the first time trying to changes a pulley and belt and I would have to say DO NOT PAY some one to do this. You could prob. be blind and pull this off. It's real easy and not hard in any way. Again thanks for the help