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Shimano Ultegra RX RD-RX805 Di2 11-Speed Rear Derailleur

Mfg PartNum:IRDRX805GS
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Backorder: This item is currently out of stock but is available to purchase today as a backorder. The expected availability date shown above is our best estimate as to when it will be shipped to you, but this date is subject to change based on our receipt of this item from its vendor. Shipping in the continental US is free for all backorder items (for international orders, our customer service team will contact you when the item is available to ship). Your credit card will not be charged until your item ships (Paypal requires payment up front, but you can cancel for full refund). Anytime prior to shipment, your backorder can be cancelled by contacting our customer service team.

The Shimano RD-RX805 Ultegra Di2 11-Speed Rear Derailleur introduces a clutch to their iconic electric road derailleur, delivering improved shift performance and stabilization. With the prevalence of off-road and multi-surface riding, the Ultegra RX uses the Chain Stabilizer mechanism adopted from mountain bike design, now adapted and tuned for road drivetrains. With an on/off switch, the RX805 puts the control at your fingertips enabling you to engage the clutch before a gravel ride, or turn it off when you're out for intervals.

The Shimano RD-RX805 Ultegra Di2 11-Speed Rear Derailleur is compatible with all current road Dual Control Di2 levers.


  • Clutch chain stabilizer mechanism adopted from MTB design.
  • Shimano Shadow RD Plus technology.
  • 11-Speed Di2 rear derailleur compatible with current road Dual Control Di2 levers.
  • Max front difference: 16t.
  • Total capacity: 39t.
  • Low sprocket min/max: 28t/34t.
  • Top sprocket min/max: 11t/12t.
  • Firmware update by E-Tube Project.
  • Weight: 280g.

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: IRDRX805GS 

Ordered by Most Relevant First
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1 stars
Reviewed 10/4/2018
by Lou P.
Competitive Racer
Fruita, CO
Value Rating
Overall Rating
1 of 1 customers found this review helpful.
Typical Shimano Quality

It took me awhile to get this to work properly. After a few attempts I went to the shop manual and followed directions exactly, and the derailleur works great. It's taking me awhile to make the shift to installing Di2, compared to cable actuated drivetrains, but once it was setup properly, it's great! Fast, quiet and I love the effortless shifting. B screw adjustment is critical, take note.

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Reviewed 10/29/2018
by Anonymous
Overall Rating
1 of 1 customers found this review helpful.
Super good for cyclocross

I have been using this derailleur in a 1x setup for cyclocross for the past month. It shifts perfectly and is super quiet with the clutch engaged.

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Reviewed 3/15/2019
by Vitaliy
Los Angeles, CA
Overall Rating
Works great

Love having clutch on my gravel bike, shifting is smooth as you would expect from Di2 components.

On my rig clears XT m8000 11-42 cassette without roadlink or similar extenders.

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