Is a smaller length belt required with a 15% pulley?

 

........no.......

 

It is not required, but you may want to consider it. I have a 15% reduction pulley and have ordered the JCW belt to install in place of the stock sized belt. There are other manufacturers such as NAPA that have a smaller sized belt, as well. Perhaps someone will chime in with that info or you can so a search. I remember seeing the subject before.

 

Do it! Without it you are at the outside edge of the tensioner's range. No reason not to.

 

I have had the 15% for about 8K miles with stock belt. Still plenty of range on the tensioner... about 1/4 inch showing when installed and hasn't changed. Randy Webb doesn't change when he installs a 15% pulley. I've been to 3 of his Pully Parties and have watched him do over 45 installs.

 

I've had the 15% for about 20,000 miles now with the original belt. Tensioner still looks fine. I did order a JCW belt for when I do change it, probably around 60,000 miles or so.

Nik

 

I'm not comfortable unless I can see at least 1 hole in the tab at the top of the tensioner. That said, for general street use if your not getting into the high revs very often and it ain't slipping its probably just fine.

 

I know this sounds like a smart ***, but it really is the Aerospace Engineer coming out.... SO your point

Your example follows the logic that happen on the Apollo program. A 24 volt supply was hooked up to a 12 volt pump. On Apollo's 7-12 things were just find. On Apollo 13 things did not work so great and I think most people know the rest. Remember the oxygen tank bursting?

I know in Aerospace we are very critical of having things work to the n'th degree, but it is your car. I am looking into getting the JCW belt for my 15% pulley.

Gee do you think the Mini Engineers may have a clue???

 

Gee do you think the Mini Engineers may have a clue???

Is that why they didn't go to 15%?

 

jlm's new tensionser might be the ticket for many.

 

FWIW, I've tried the JCW belt with my 15% pulley and it instantly started squealing like Ned Beatty in "Deliverance". Neither the well-worn stock belt, nor new or used 535's made the same kind of racket.

 

Anybody know for sure that the JCW belt is in fact shorter that the stock belt?

 

A reliable insider told me that Mini engineering spent a great deal of time makeing sure that the JCW belts would not be compatible with P&D or Alta pulleys. Now that's engineering!

 

Napa 060539 I found to be the ticket. Some have used the 060535 but its so tight you are putting the full force of the tensioner on it and causing it to wear out quicker due to the friction and to much tension.

 

SUUUUUUU WEEEEEEEEEEEEEEEE!!

 

That's fascinating, guess I'll soon find out!