Shimano Dura Ace RD7900 Rear Derailleurs are compatible with wider range cogsets and can accommodate a maximum 28 tooth cog. Compatible with 9 or 10speed Shimano drivetrains Not compatible with DuraAce 8speed shifters Large 11tooth pulleys with sealed bearing for smooth, quiet running DuraAce 7900 rear derailleur features carbon pulley plates and a wider gearratio yields triple capacity without a GS rear derailleur Cage Length Short Drivetrain Spacing ShimanoS
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