Shimano dura ace r9100 11sp rear deraillleuradopting race proven technologies from shimano's mtb range, the dura ace r9100 road rear derailleur now brings the shadow technology to road cyclists'. '.strtoupper('t')he shadow design places this road bike rear derailleur under the chainstay and cassette to give a slimmer profile, which not only improves aerodynamics but helps prevent damage in a crash.this revised shadow design brings you precise and faster gear shifts than on previous models plus even faster wheel changes for race days'. '.strtoupper('t')his is thanks to the shadow feature moving the derailleur out of the way of the rear dropouts.the dura ace r9100 road rear derailleur derailleur only comes in one length and will work with cassette sprockets up to 30t'. '.strtoupper('t')his means that this rear mech offers a greater rider tuned ratio than previous editions'. '.strtoupper('f')eatures  maximum sprocket 30t  minimum sprocket 11t  maximum front difference 16t  total capacity 35t  stable shifting performance  distance between pulleys is maintained through the shifting range  shimano shadow rd construction  low profile rear derailleur design  race endurance for less damage in crash  adapted for race specific frame design  mount type standard mount    manufacturer's part number rdr9100ss    weight 158ga 2 year warranty is offered with all shimano products from chain reaction cycles 3 years on dura ace and xtr products.buy shimano components from chain reaction cycles, the world's largest online bike store.