The XTR CS-M9000 11-speed cassette makes use of a variety of materials to maximize strength while minimizing weight. 4 carbon fiber arms support a 40 tooth cassette made of aluminum. The next 6 cogs are titanium and the last, smallest four are steel.

Shimano's goal with their mountain gearing is to make both front and rear shifts be perfectly spaced. This avoids leg overspin where momentum and efficiency is lost due to an awkwardly large gearing step. Shimano calls their perfectly spaced gearing Rhythm Step Gear Progression designed to make gear changes feel very smooth and natural so you can maintain maximum trail speed. A HG-X11 specific tooth profile means seamless shifts with zero chain clatter. Use this cassette with the XTR CN-HG900-11 chain for the best performance.