With a focus on gear steps to help maintain performance and maximum cadence control, Shimano's CS-M5100 Cassette for 11-speed drivetrains keeps you churning the correct cog no matter the terrain. The wide gear range may postpone your drop-in for the 12-speed group a bit longer, as the M5100 is undoubtedly designed to be a dependable workhorse and a worthy weekend racer. With terrain specific options, the 42-tooth or 51-tooth, you can ride long tempo climbs or have bail-out, switchback crusher. And the 11-speed design still allows a fast downhill 11-tooth cog to motor back to the trailhead.