Recently had an Alta 15% pulley installed on my 05MCS(8,500 miles). My mechanic recommended a new NAPA belt: Stock # 060539. He thought my stock belt was a little loose. Only have had pulley on for 100+ miles, no problems so far. He didn't have one at time of the install. How much labor involved? Insights, suggestions please concerning putting new NAPA belt on. Thanks. Nick

 

You can use the stock belt with a 15% pulley. I have the m7 16% pulley on my Dark Silver MINI with the stock belt. I would suggest you use the factory belt instead of the NAPA one. It's good practice to change it if you have it off, but with only 8500 miles you should be ok. If it's routed correctly, it should fit fine.

 

I highly recommend that you don't use a stock belt. It costs like 20 dollars for a new one, or something, and you'll be saving a lot of 'imperceptible' belt slippage and accelerated wear. You'll also be saving some lost power . Do it right, do it the first time!

 

I ran the stock belt for 30+ thousand miles with no problems. Then I switched to the JCW belt after that (about 20K ago). Again no problems. The only thing you'll need to change it is the tensioner tool.

Nik

 

I have the napa belt with %17.