Sram xx1 type 21 11 speed rear mechwith its horizontal parallelogram design and pulley offset x horizon keeps the chain gap constant across all 11 gears providing fast precise shifts by limiting all movement to the horizontal axis this design is faster reduces shift force and eliminates ghost shifting roller bearing clutch technology reduces bounce and chain slap cage lock technology makes wheel removal and installation easier than ever before paired with the xx1 shifter the x h