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Ultegra Di2 RD-R8050 Rear Derailleur

  (3 customer reviews)
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MSRP $269.99
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Silent as a shadow.

With Shimano's new Shadow technology at play in their redesigned Ultegra Di2 Derailleur, Shimano is ensuring that you get effortlessly easy, intuitive shifting all ride long. With a redesigned body, the Ultegra RD-R8050's sleek integrated appearance and optimized slant angle improve the responsiveness, performance, and stability of shifts. With their Synchronized Shift technology, the front and rear derailleurs communicate with each other to ensure that you're always in the optimal gear placement, shifting the front derailleur automatically with the rear, or vice versa.

The Shimano Ultegra Di2 RD-R8050 Rear Derailleur is available in two sizes, the Short Cage SS version will accept up to a 30T rear sprocket, while the Medium Cage GS version will accept up to a 34T sprocket.


  • Redesigned rear derailleur features low-profile sleek body with optimized slant angle.
  • Shimano Synchronized Shift technology ensures you're always in the optimal gear placement.
  • RD-SS covers 11-25t to 11-30t.
  • RD-GS covers 11-28t to 11-34t.
  • Claimed weight: 242g (SS), 249g (GS).
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by DonWA
Cycling Enthusiast
Palatine, IL

To Shimano's credit they made this derailleur fully compatible with the previous Ultegra 6800 series shifters so upgrading to the 34-tooth cassette doesn't require a whole new groupset. The shifting is as smooth as I have come to expect from Shimano. With this derailleur and the 34-tooth cassette I don't even think about hills anymore. I can conquer anything above sea level.

Reviewed 7/15/2018
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by DonWA
Cycling Enthusiast
Palatine, IL

I already had the Shimano 6800 series electronic shifting but the biggest cassette you could get with it was 32 teeth. When Shimano introduced the 8000 series with a 34 tooth cassette I jumped on it to help save my knees. To Shimano's credit they made the new 8000 series derailleurs fully compatible with the 6800 series shifters so if you want to upgrade to the bigger cassette you don't need to buy the complete groupet. You only need to replace the rear derailleur, cassette and chain. And the shifting is flawless. Very smooth and fast shifts. You will appreciate the performance.

Reviewed 7/10/2018
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by davidshiloh4
Cycling Enthusiast
Denver, Co

I've had this for a few weeks and so far it is Flawless. It shifts great and gives you the ability to have an 11-34 cassette which works great in the Denver area where we love to climb mountains.

Reviewed 4/12/2018
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