The Problem Solvers Bushnell Eccentric Bottom Bracket is the industry leading design for chain tension adjustment on tandem and dedicated single speed bikes equipped with eccentric bottom bracket shells. The classic version features full-body, aluminum construction across the shell for maximum surface area friction and additional value. Accepts English threaded bottom bracket cups (1.37 X 24 tpi) Classic, full-body design made from aluminum Fits BB shells from 53.8 - 54mm I.D. Fat Bike width (100mm) Silver finish Weight - 310 grams Specifications Weight 310