This is info I dug up on belts for smaller pulleys. I am perfectly satisfied with the Goodyear POLY-V Gatorback on my 17%. Since it was brought up in a another thread that availability was not easy and another manufacturer was brought into the picture. I started looking into Dayco belts and discovered they may have been the originator of the design in 1979.
Here is what I found;


NAPA OEM replacement part # 25-060547 < stock size replacement

 

I've been using the Dayco belt with a 19%, and have been very happy with it. Absolutely no issues.

Scott
90SM

 

Scott, your post is what I was looking for. Anyone else want to share info/details, part numbers on belts they are having good service or failures with.
Remember, a failure of this simple part can leave you on the side of the road and you will be late.
I know there are a lot of pulleyed MINI's out there.

 

I just threw Napa belt 25-060539. Had the stock one to replace it with thank god.

I installed the Napa belt when I installed the m7 tech. 16% pulley. The belt seemed kinda tight when I put it on so I'm thinking that was the cause for the failure. We'll see.