Looking for opinions, perhaps even consensus, on the current wisdom concerning the appropriate belt size to run on my set-up: Alta 15% reduction sc pulley combined with Alta 2% oversize crank pulley. I currently run stock belt size.

Any feedback will be appreciated. Looking for quick, up to date information, I have already searched and read what is out there, and I am a bit confused as to whether stock length or the shorter NAPA belt would be best.

Len

 

How much extra circumference (over the stock pulley) is there on your 2%? Take that number and multiply it by the percentage that the belt wraps around said pulley. Now add that to roughly -.8in. With that figure in hand, the belt you are searching for should be that much reduced from the stock belt size.

- Matt

 

Here ya go..

 

I have posted this chart before and was told that the chart has been proven that some of those sizes oare wrong.

But I am running the 060535 for my 19% pulley.

 

I guess someone should tell Alta then since that's where this is coming from...

http://www.altaminiperformance.com/p...Pulleys-15-19-

 

You may have been told some of the sizes are wrong only in regards to the recommendation of the stock belt size for the first 15% reduction pulley...it has been shown to not be tight enough.

I do not know about the relation in regards to an altered crank pulley size as well.

- Matt

 

I have the same set-up and I'm using the stock JCW belt which is a tad smaller than the stock S belt.