Shimano Ultegra RX Di2 RD-RX805 11-speed Shadow Plus Rear Derailleur

Item number: 65038
Ultegra RX Di2 RD-RX805 11-speed Shadow Plus Rear Derailleur - dark grey/long
Ultegra RX Di2 RD-RX805 11-speed Shadow Plus Rear Derailleur - dark grey/long
Ultegra RX Di2 RD-RX805 11-speed Shadow Plus Rear Derailleur - dark grey/long
Ultegra RX Di2 RD-RX805 11-speed Shadow Plus Rear Derailleur - dark grey/long
  • 100 day return period
  • Online since 1998
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The Ultegra RX Di2 RD-RX805 Rear Derailleur by Shimano - The Advantages of Shadow Plus

The Ultegra RX Di2 RD-RX805 Rear Derailleur by Shimano gives you new options for your 11-speed gearshift, which opens the door to advantages of Shadow+ technology, and thus is particularly appealing for cyclocross, gravel and adventure bikers. Friction is effectively reduced thanks to stabilisers that can be switched on or off, preventing chain hitting and dropping. When navigating rough, unpaved trails and paths, riders benefit not only from Shimano's exceptional brake precision and the user-friendly Di2 interface, but also gain a significant degree of added safety. The rear derailleur is mostly made of aluminium and is only available in a GS version with a longer cage, which can switch cassettes ranging between 11-28 and 11-34 teeth. The direct mounting option is also perfectly suited for frames with thru axle dropouts.

Information regarding the return of batteries and electrical equipment:

Information on the return and disposal of batteries and electrical equipment can be found here.


Series: Ultegra RX Di2
Application: Cyclocross, Gravel, Road
Gearing: 11-speed
Mount: standard (Direct Mount compatible)
Capacity: 39-tooth
Compatibility: Shimano Road 11-speed

Technical Information:

Derailleur Pulleys: 11-tooth
Outer Cage Material: Aluminium
Inner Cage Material: Aluminium
Other Materials: aluminium, composite (GFRP), steel


Power Cable: EW-SD50 (1 x connection)
Shift/Brake Lever: ST-R9150, ST-R9160, ST-R9170, ST-R9180, ST-9070, ST-R8050, ST-R8060, ST-R8070, ST-9071, ST-6870, ST-6871, ST-RX815, ST-R785
Cassette: CS-R9100, CS-9000, CS-6800, CS-5800, CS-R8000, CS-HG800-11, CS-R7000, CS-HG700-11
Chain: CN-9000, CN-6800, CN-HG901-11, CN-HG701-11, CN-HG601-11, CN-LG500


- chain stabilizer mechanism (Shimano Shadow RD+) from the mountain bike sector
- on/off switch
- painted cage plates
- derailleur pulley bearings
- 4 pivot bushings, fluorine-coated
- E-Tube project ensures firmware updates


Digital Integrated Intelligence (Di2)
Di2 systems are the electronic shifting systems from Shimano. They are based on the SEIS, the Shimano Electronic Intelligent System, which takes over the index shifting function from the mechanical components, only via power cables or radio signals and not via a Bowden cable. Shifting is done by simply pressing a button. This has the advantage that no great effort is required, your concentration on the ride is not disturbed and operation is easy even with cold hands. In addition, the electronic gear changes are very fast and highly precise. There is also no risk of a defective circuit due to dirty cables or other problems. You can adjust individual settings via the E-Tube Project, such as adjusting the shifting speed, the number of shifting operations per button press or the Synchro or Semi-Synchro shifting function. Shimano offers an app for this purpose. Gear maintenance and firmware updates are also done via E-Tube, with the bike connected to a PC running the appropriate E-Tube software for more extensive workshop work.

Shimano Synchronized Shift
Shimano's synchronised shifting function is a shifting mode that automatically matches the Di2 rear derailleur and Di2 front derailleur. It is activated either via the E-Tube platform or via the rear derailleurs with a function button. Synchro Shift means that the front derailleur automatically selects a suitable gear depending on the position of the rear derailleur, while Semi-Synchro Shift means that a suitable rear derailleur position is automatically set when you operate the front derailleur. This gives you the advantage that you only have to concentrate on one side of the shifting process and are not thrown off-rhythm by sudden unfavourable changes to the gear ratio.

Shadow RD+
Shadow Plus rear derailleurs are just as low-profile as Shimano's Shadow rear derailleurs. In addition, a stabilizer with on/off switch is used to reduce chain slap and thus counteract chain drop. At the same time, this results in a quieter drive. Weight is also saved compared to other chain restraint devices.


Cage Length: GS
Max. Largest Sprocket Teeth: 34-tooth
Min. Largest Sprocket Teeth: 28-tooth
Max. Smallest Sprocket Teeth: 11-tooth
Min. Smallest Sprocket Teeth: 11-tooth
Max. Chainring Difference: 16-tooth
Total Capacity: 39-tooth
Manufacturer Number: I-RDRX805GS


- 1 x Shimano Ultegra RX Di2 RD-RX805 rear derailleur


  • dark grey/long: 280 g


  • dark grey/long, out of stock

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