Over time the OEM rubber bushing will break down, and allows the back of the shifter stay to move more than it should. The Kartboy Rear Shift Bushing is made from a much stiffer urethane, meaning it won't break down over time, and won't flex nearly as much as the oem unit. What this means is a more postive snap into gear, and no more of that vague feeling in the stick when it's reached the end of the throw travel.