The sram xx1 11 speed rear derailleur with its ldquohorizontal parallelogramrdquo design and pulley offset the sram xx1 11 speed rear derailleur 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 by eliminating unwanted chain movement x horizon shifts faster puts an end to ghost shifting and reduces shift force and chain