Rhythm is the "magic word" when it comes to harmonious power transfer, and the key to this is an optimal gear gradation that caters to different terrains. The 11-speed cassette CS-M9000 with 11-40 teeth is the cassette with the widest gear range that Shimano has ever brought to market. At the same time, it is also the most carefully graduated. The Rhythm Step gradation allows for precisely calculated gear shifts without harsh jumps, which saves energy and maintains the flow on the trail.