Each component has been re engineered to ensure maximum stiffness performance and minimum weight first introduced in xtr di2 m9050 shimanorsquos innovative synchro shift is now available with dura ace r9150 available as a programmable di2 option synchro shift creates an intuitive experience on the bike through synchronised front and rear shifting that can be custom programmed by riders in addition to traditional ldquofullrdquo synchro shift riders can optionally select ldquosemir