XTR SM-BB93 Bottom Bracket
XTR SM-BB93 Bottom Bracket, In the world of Shimano, the letters XTR stand for the best of the best, and the English-threaded SM-BB93 Bottom Bracket is exactly that. It's tough, extremely lightweight, and sealed to keep out dirt in the worst riding conditions imaginable. The M-BB93 fits 24mm crank spindles and is compatible with 68mm and 73mm bottom bracket shells.