OE Spacers typically wear out within a year of hard riding. OE wheel spacers should be checked and replaced as needed with every wheel bearing change.
Water and dirt act as a grinding compound between the seal face and the mating surface of the spacer. Once the grooves are deep enough, the sealing surface is lost allowing water and dirt to pass through and contaminate the bearing.
The AB aluminium spacers feature a hardened steel shell pressed over the aluminium to provide superior wear surface.
The AB steel spacers are manufactured with 52100 bearing steel that is through hardened and precision ground and plated for years of service.