Hope mtb stainless steel 30mm bottom bracket fitted with high quality seals and bearings our threaded bottom brackets are renowned for their durability features external bottom bracket designed for threaded bottom brackets custom swiss made bearings are double sealed which gives a much greater life span than stock units free running labyryinth seal protects bearings and has less drag bearings stainless steel bb shell bsa thread bb shell frame width 68 73mm crank spindle diameter 30mm wei