DUB technology features a better engineered bottom bracket and a new spindle design for a more uniform approach to bottom bracket fitment, better sealing against contamination, and a new measure of durability For use with all SRAM DUB cranks and 68/73mm BSA threaded shells BB Shell Thread: British BB Shell Width: 73mm BB Bearing: Steel Crank Spindle Diameter: 28.99mm Interface: DUB