BB90 is the Trek oversized bottom bracket standard and is only found on Trek road bikes. The shell is 90.5mm wide and is designed to work with 24mm spindles and road cranks and have the bearings inside the shell. The CeramicSpeed Bearings come as two bearings, which are then pressed into the frame.Those two bearings consist of standard super smooth, super round CeramicSpeed Balls contained in hardened-steel races, resulting in lower drag and longer life. BB90 is simple and light. The standard is designed to work with 24mm thru-axle spindles. The bearings work with Shimano and other 24mm thru-axle cranks, like FSA. The CeramicSpeed Standard Bearings last at least 3 times longer than other bearings. That’s thanks to hardened-steel races and CeramicSpeed Balls that are 100% smoother & 15% harder than the ceramic competition. These bearings have a frictional drag of 0.3-0.4 watts per set, which represents an average 75% drag reduction compared to stock bb’s.The CeramicSpeed Coated Bearings reduce drag by 50% compared to Standard Bearings and an improvement in bearing life of 60%. To better adjust the performance to your needs, consider the grease you’re using. All Round Grease comes installed, but can be changed for lower drag TT and Track Grease, or higher durability LongLife Grease, which adds a bit of drag but stays in when riding through messy conditions.