The CeramicSpeed BB30 Shimano Road bottom bracket opened up design possibilities for frames.To fit Shimano cranks you need a special machined aluminum threaded bottom bracket that self-threads.They are finished with CeramicSpeed bearings.You have two options in terms The first option is standard low strength, long life bearings with hardened steel races and the super round CeramicSpeed Balls.The second option is coated bearings, which use those same balls installed on coated tracks.hardened steel for longer life and less rolling resistance.This bottom bracket works with cranks that have 24mm thru-axle shafts.Bottom brackets have several variables, but within that, CeramicSpeed standard bearings typically have a friction drag of 0.3-0.4 watts per set.That´s in the range of a drag reduction of 75% compared to standard brackets.That´s thanks to the balls that are 100% softer and 15% harder than the competition from ceramics.CeramicSpeed bearings last at least three times longer than other bearings.Coated bearings see another big performance bump.Coated races see 50% drag reduction and 60% improvement in bearing life.Performance can be adjusted by changing the grease.All Round Grease comes installed, but can be swapped out for lower drag TT and follow-up grease, or longer-lasting LongLife grease, which adds a little drag but stays inside when driving in messy conditions.