These drives are to be used with the ADA Racing 3rd bearing support for the Bigfoot Go-Ped. They can also be used as a replacement for the stock Bigfoot drive, but doing so requires the use of a Sport drive spindle bolt (6mm x 45mm). 3.35 inch total length.
Stock spindle size is 0.625" diameter. Larger diameter spindle equals more top speed(to a point), but with slower acceleration. Too large of a spindle on a stock engine with a heavier rider will result in slow acceleration and slower top speed. Engine mods and rider weight have a big effect on spindle size.