Upgrade you stock bottom bracket. Enduro bottom brackets are designed to spin more efficiently and for longer. Ceramic bearings are not only here to stay, they are now the standard, period. When carbon fibre was first introduced, there were many riders still on steel bikes in the Tour de France, but now every racing bike is made of carbon fibre. This is the case for ceramic bearings, and the CH bearings are an excellent choice for entry into the technology. ABEC-5 tolerances and LLB seals with Graphite Nylon retainers are premium features that are not available on our competitor's ceramic hybrid bearings at two or even five times the cost. Oversized Silicon Nitride Grade 5 balls and cryogenic treatment of the ABEC-5 races ensure long lasting, smooth rolling bearings at great value.Fits BB90 frames - 37mm diameter with a shell width 90.5mm (road) or 95.5mm (mountain)Suitable for chainsets with 22mm axleLightweight, durable Delrin cupsCeramic Hybrid Bearings45.79g