Hope's well proven stainless bottom brackets make an ideal upgrade or replacement for Shimano, Race Face and with an additional conversion kit (sold separately) Truvativ MTB cranksets - Not suitable for road bike cranksets.The machined aluminium cups hold full stainless steel INA Swiss made cartridge bearings which are custom made to give much greater life span than stock units and are also replaceable to reduce wastage and minimise expense. The bearings are designed to run directly on the crankset axle, without the use of shims or spacers which further increases lifespan and reliability when combined with the non contact, free running external labyrinth seal and o-rings on on internal aluminium centre tube. Compatible with most 24mm axle MTB cranksets - Not suitable for road bike cranksets.