Upgrade you stock bottom bracket. Enduro bottom brackets are designed to spin more efficiently and for longer. Precision machined Delrin cups are lightweight and extremely durable, whilst ensuring perfect chainset alignment.Proven time and again in World Cup race conditions, the ZERO Ceramic bearings are the ultimate race day weapon. Oversized Grade 3 balls roll on races which are ground to a mirror finish after receiving Magnetite and then Cryogenic treatments for hardness and longevity. More durable and with even lower rolling resistance than any 2RS bearings, they come closer to that magic ÒzeroÓ rolling resistance number. ÊEnduro Bearings uses Silicone seals which are more slippery than rubber seals used by other ceramic bearing suppliers.Fits BB92 frames - 41mm diameter with a shell width from 86mm to 92mmSuitable for chainsets with 24/22mm axleLightweight, durable Delrin cupsZero Ceramic Bearings65.00g