I have bought a 2nd hand cooper S and the previous owner told me that it has a Hartge reduced pulley but cant remember how many % reduced it is. I had the drive belt changed recently and it requires a shorter belt. Any ideas how i could find out the % reduced of the pulley im running.

Cheers,
Ted

 

Hartge pitch diameter: 56.5mm = 13.74% reduction

 

they only have 13.74% is it ? They don't offer 15%,17% or a 19% ?? The previous owner reckons that it's 18% but i have been searching all over the forum and i dont believe that a 18% pulley exists. thanks anyways

 

AFAIK - yes.