Class leading xtr 10 speed dyna sys chainset integrating the bottom bracket and chainset into a strong rigid yet lightweight unitintegrated design makes installation and adjustments easier than everprecision bottom bracket bearings are spaced further apart and are therefore more stable and longer lasting than conventional bottom bracketssuper lightweight hollowtech ii forged duralumin crank arms hollow design saves weight whilst increasing rigidityeasy to use splined bottom bracket spindle con