The bottom bracket bearings for the hollowtech ii fcr9100 crankset which is the ultimate crankset for stiffness whilst keeping weight low for performance riding and racing key features minimal bearing interface gives superbly smooth rotation distinctive style that exudes quality and perfection required for installation of fcr9100 chainset with a choice of english or italian thread bb cups use tlfc34 or tlfc24 in conjunction with tlfc36 adaptor tool for installation and removal