Ceramic Speed BB ALPHA Bottom Brackets Low Friction, Longer Life, No Compromises Most bottom bracket upgrades ask you to trade durability for efficiency or efficiency for durability. The BB ALPHA gives you the best of all worlds. At the core of every unit are grade-3 silicon nitride ceramic balls running in hardened stainless-steel races, a pairing that keeps rolling resistance low while resisting corrosion and wear far longer than standard steel. Custom-engineered light-contact seals sit over each bearing, and the backs of those seals are lined in stainless steel for an extra layer of protection. With better moisture resistance, lighter cups, a simplified spacer-tube system to trim weight, and straightforward installation, this is the last bottom bracket you'll put on your frame. Quality ceramic balls roll with less friction than steel and resist corrosion, so you carry less drivetrain drag on every pedal stroke Stainless-steel races provide exceptional corrosion protection and added bearing support to better handle preload over the long term Custom-engineered sealsdeliver up to 500% better moisture protection over previous generations without sacrificing the low-drag character the brand is known for Plastic dust covers add a rigid final barrier against contamination, refined through 28 design iterations before production Simplified spacer-tube design and lighter cups cut weight 10% versus the previous generation and reduce installation complexity BOTTOM BRACKET SPECIFICATIONSModel BB92 SRAM DUB MTBBSA Shimano MTBBSA SRAM DUB MTBShell Type Press Fit (BB92)Threaded (BSA)Threaded (BSA)Shell Width92mm73mm73mm Spindle Diameter28. 99mm24mm28. 99mm Crank Compatibility SRAM DUBShimano (24mm spindle)SRAM DUB | Ceramicspeed | Bb Alpha Bottom Brackets Bb92 Sram Dub Mtb (92Mm Shell, 28. 99Mm Spindle)