With its BEAM SPIDER construction the new SHIMANO DEORE XT M8100 12-speed cassette shaves weight while increasing SHIMANO’s MTB gearing range another gear. Using SHIMANO’s new MICRO SPLINE freehub body and HYPERGLIDE tooth profile these 10-45 and 10-51T cassettes deliver advanced shifting performance. Lighter and stiffer construction Reduces cassette inertia resulting in faster acceleration and increased chain security 10T lowest sprocket realized by new FREEHUB body construction Definitive shifting performance MICRO SPLINE Wide range and close step 12-speed drivetrain