Shimano Dura-Ace RD-R9100 11-Speed Rear Derailleur

With the Shimano Dura-Ace RD-R9100 Rear Derailleur, Shimano borrowed some tech from their mountain-bike derailleurs to improve the breed. The design looks different than the 9000-series because the bolt that affixes the derailleur to the frame is not also the pivot for the derailleur. That pivot has been moved rearward and down. The entry point for the cable has also been moved for more efficient routing. The first change does two things. It moves the derailleur so it’s almost under the right chainstay, thus better shielding it from a right-side impact. It also makes it easier for the derailleur to handle shifting the chain across an 11-30 cassette, which Shimano also released with this group. The second change makes shifting more efficient as well as shortening the cable and housing-lighter and less flex. You’ll also notice a longer cage. It’s carbon for minimizing weight. The pulley pivot is designed so that the upper jockey wheel maintains a constant distance from the cogs, which improves shift performance across the cassette range. Inside the cage are two eleven-tooth pulleys with deep cut-outs. These both lighten the pulleys for greater efficiency and make it harder for dirt and grit to get packed onto the pulleys, keeping your chain cleaner and faster. The amount of cable moved is the same as with the Dura-Ace 9000 rear derailleur. As such, you should be able to use 9000-series shifters with this derailleur.