The Shimano GRX Di2 RD-RX815 brings electronic precision to gravel and adventure riding with 11-speed digital shifting, a medium cage profile, and the signature SHADOW RD+ chain stabiliser — so your drivetrain stays quiet and controlled whether you're on smooth tarmac or rough gravel tracks.

Highlights

• Shimano Di2 electronic shifting — instant, precise gear changes at the touch of a button
• SHADOW RD+ clutch mechanism reduces chain slap and prevents chain drops on rough terrain
• ON/OFF clutch switch lets you dial back tension for easy wheel removal on smoother rides
• Medium cage suits 2x11 gravel drivetrains with cassettes up to 34T
• Supports Synchronized Shifting for seamless front/rear coordination
• Compatible with conventional direct-attachment and direct-mount interfaces

SHADOW RD+ Technology

Shimano's SHADOW RD+ design tucks the derailleur profile close to the bike for added protection on tight singletrack and gravel descents. The integrated chain stabiliser applies controlled tension to dampen drivetrain movement, keeping the chain seated under the vibration and impact forces common in off-road riding.

Di2 Electronic Precision

As part of the GRX Di2 ecosystem, the RD-RX815 delivers consistent, repeatable shifts regardless of rider fatigue or cable stretch — because there are no cables. The electronic motor shifts with the same authority on lap one as lap one hundred. Pair it with the GRX Di2 Synchronised Shifting feature to let the system automatically trim the front derailleur as you move through the cassette, eliminating chain rub without manual intervention.

Compatibility & Fit

The RD-RX815 is designed for 11-speed Shimano GRX Di2 groupsets running a 2x drivetrain. It accepts cassettes with a maximum low sprocket of 34T and a minimum of 30T, with a total drivetrain capacity of 38T and a maximum front chainring difference of 17T. Compatible with conventional (hanger) and direct-mount rear derailleur interfaces. Requires a Shimano Di2 junction and battery (sold separately).