High performance applications often reveal problems with stock power train components that were never anticipated by the designers. One such problem is the tendency of the stock inner primary bearing race on late model big twins to shift on the transmission main shaft under high torque loads. This "walking" of the race can result in the destruction of the transmission main shaft seal, and ultimately the main shaft, output gear and output gear bearing. Costly repairs and annoying down time. A unique modification to the design of the main shaft inner primary bearing race, positively prevents it from "walking" into the main shaft seal and output gear. The S&S bearing race features an extra step on the inside diameter that acts as a stop on the transmission main shaft. When the race is pressed on to the shaft, the step will not allow the race to move inward toward the main shaft seal. Can be retrofitted to stock and aftermarket transmissions.