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

Mfg PartNum:IRDR9100SS
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Shimano's RD-R9100 Dura Ace Rear Derailleur incorporates the Shadow design that made its debut on their mountain bike drivetrains. This low-profile construction better tucks the derailleur body beneath the cassette for more stable shifts, quicker wheel changes, and less exposure to possible damage in a crash. It also keeps a consistent distance between the upper pulley and the cogs across the entire gear range for more precise and reliable shifts on wide range cassettes.

Compatible with Shimano 11-speed road drivetrains.


  • Low-Profile Shadow RD Design
  • Largest Cog Size: 30T
  • Minimum Cog Size: 11T
  • Maximum Chainring Difference: 16T
  • Total Capacity: 35T

B-Stock - This product has one or more B-Stock units available. These units can be purchased at a discount (see option select). B-Stock units were returned from other customers and may have missing or damaged packaging materials. These units are otherwise as new. The full manufacturer warranty applies. Click Here for more information.


Mfg PartNum: IRDR9100SS 

Ordered by Most Relevant First
5 stars
4 stars
3 stars
2 stars
1 stars
Best of its class
by Olivier
Competitive Racer
San Francisco Bay Area

Precise shifting. Light. Easy to install. Only issue I have had so far is that the pulley/jockey wheels are on the noisy side of things. Nothing alarming, but it seems to be taking more time to "break in" than Ultegra.

Reviewed 7/12/2021
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The design improvements reflect Shimano's high regard to provide seamless shifting.
by Anonymous
Cycling Enthusiast
Grass Valley, CA
2 of 2 customers found this review helpful.

I use this on a Cannondale SuperSix High Mod that was originally equipped with a Dura Ace 9000 rear derailleur. While the DA 9000 shifting was excellent, it was a short-cage derailleur, and I wanted to switch to an 11-30 cassette. I am now 71 years of age and I still regularly climb gradients that can easily exceed 10%. The Dura Ace R9100 coupled with an Ultegra 11-30 cassette has not only made for quieter shifting, but it has made it just a little bit easier to climb the most challenging hills around my neighborhood. I also like the shadow design, and, even though I purchased B-Stock at a nice discount, there were no flaws in the derailleur whatsoever. I am very happy with this purchase.

Reviewed 1/28/2021
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Superb function. Gorgeous to look at.
by Loren
Cycling Enthusiast
Seal Beach, Ca

I'm an older, semi-fast recreational road rider with over 30 years experience with top of the line group sets. These include Campy, Shimano and even Suntour. I had a full Dura Ace 7900 group on my Litespeed Archon T1 and the shifting was dialed. In fact everything worked so damn well. But then I decided to do an upgrade to a Dura Ace 9100 mechanical group, mostly because I just dig the hell out of the way it looks. After I installed, adjusted and rode the new set up, I was just amazed that the front and rear shifting was far better than the 7900 group. Another thing that I'll have to wait to verify, but the drivetrain is silent. I haven't had much riding time on it, maybe 150 miles and haven't lubed the Dura Ace chain yet. It still has the packing grease. I'll see what it sounds like when I lube it.

The reason I only gave 4 stars for value is that I'm pretty sure Ultegra would function just as well, but at 12 the price. The glossy finish on the Dura Ace makes me swoon.

Reviewed 4/26/2019
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