All Balls 11-1057 Wheel Spacer Kit Outlaw Racing's Wheel Spacer kits are designed for years of service even in the dirtiest riding environment. OE Spacers typically wear out within a year of hard riding, OE wheel spacers should be checked and replaced as needed every time the bearings are serviced. Water and dirt act as a grinding compound between the seal face and the mating surface of the spacer, so once the grooves are deep enough, the sealing surface is lost allowing water and dirt to pass through and contaminate the bearing. The aluminum spacers feature a hardened steel shell pressed over the aluminum to provide superior wear surface. The steel spacers are manufactured with 52100 bearing steel. Precision ground and plated for years of service.