When to change belts?

[claudeG]

im just about to install 15% red. pulley, is it recommended that i change belts at the same time too? car has 100 000km and not gone for its major service yet ( inspection 2). i already have ngk iridiums to go in. Please help, thanks

[Richard Crofts]

Its advised by several well recommended UK companies that you go for a smaller pulley belt when you do the reduction...reduces the chances of the belt coming off. At the very least change the standard belt for a new one as after 100k the old one will have stretched a bit and on a smaller pulley will probably be very slack and have both increased slip and chance of coming off totally.

R

[claudeG]

what are the belt specs required for a 15% red. pulley? iether need to import or try find something local then
thanks

[Capsaisin]

If you have any difficulty locally finding the correct belt, you could get a JCW belt from the BMW dealers. The part number is 11280300802. This should work OK with the 15% reduction pulley and would be much better than using the standard belt.