Hey all,

I'm gonna be doing a 30t conversion soon on my '12 SG and was wondering what diameter belt to use.

I know oem is 1" x 140t, and I know I need a 139t belt, but what diameter? Will a 1 1/8" belt work or is the rear pulley only 1"? If I can go a little bigger, is there a benefit as far as tensile strength?

I have a FM 107" with @103hp and, with the pulley, probably around 126tq. I'll be doing the heads soon, too, bringing the hp up a little.

Thanks.

 

Wider is better but I believe you are limited with the stock pulley on how wide. I am not sure of the limit, measure in between the flanges.

 

I would, but it's still in storage at my cabin. Probably won't bring it home for a couple more weeks and I'd like to get the belt ordered.

There's no rush, however. I just figured with the amount of guys that have done this conversion, somebody would know.

Thanks for the reply.

Tim

 

One piece of advice I will give you. Go with a Gates belt. BDL sells them.

 

Yeah, I've noticed most on here recommend them. Thanks for the input.

Does anyone know how wide the rear pulley is? I'm not near my bike to measure it.

 

The rear pulley dictates belt width, the front pulley is much wider. If you currently have a 1" belt, stay with that size. Harley has also used 1 1/8" and 1 1/2" over the years, but they will not fit your pulley.

 

That's kinda what I figured, but wanted to be sure.

I ordered a Gates Polychain from BDL yesterday and a couple tools to do the job.

Thanks.