am bb dub englishbsa mtb 73mm cannondale aiThe SRAM AM BB DUB English BSA (MTB) 73mm Cannondale Ai is part of the new DUB bottom bracket series, designed for maximum durability, smoothness , and versatility . With a single oversized axle , the DUB bottom bracket fits all bottom bracket shell standards, offering improved crankset compatibility and increased protection from the elements. The system is significantly lighter than the classic GXP, which translates into greater drivetrain efficiency