Campagnolo Chorus 12s UT 172.5x52/36 UT crankset carbonCampagnolo Chorus Crankset 172. 5mm 12 Speed 52 36t 96 BCD Campagnolo Ultra Torque Spindle Interface Carbon. The Campagnolo Chorus 12 Speed Crankset features lightweight carbon crank arms and is optimized for Campagnolos Ultra Torque crank system. Utilizes Campagnolos Ultra Torque crank system to provide a very light weight and stiff system that transfers power to the pedals without power loss Directly molded unidirectional carbon fiber cranks steel