When reducing the diameter of the upper pulley it is common to replace the factory 90mm idler with a 100m version to help increase belt wrap. These pulleys are made out of 6061 billet, anodized black and comes standard with a pair of Italian made high speed bearings and Spirolox bearing retainer to maintain balance at high speed. Also included is two bearing spacers designed to be used with the factory bolt for ease of installation.
This pulley is 42mm wide allowing the use of up to an 11 rib belt. Pulley offset works on the LSA and LS9 supercharger belt drive system.