underdrive pulley ?

[mustangmat99]

i was reading the forums awhile back and someone asked something bout if they got a smaller pulley would it mess anything up as in needing a smaller belt or being to small of a pulley to power everything, my quesiton is this i dont know much about all the pulleys and all that, but on rpmoutlet.com they have the 42% reduction pulley, if i got that, would i have to get another belt? like a shorter one?

 

[Lsredy2kstang]

Yes, when you go with an underdrive pulley you need a shorter belt to compensate for the underdrive pulley being smaller.

 

[mustangmat99]

i figured so, would there be a certain size i need to get? how would i know how long i need it to be?