Shimano GRX RD-RX815 Di2 Rear Derailleur – 11-Speed, 34T Max, Shadow Plus

The Shimano GRX RD-RX815 Di2 Rear Derailleur is designed for gravel, endurance, and mixed-surface riding. Built specifically for 2x 11-speed GRX Di2 drivetrains, it offers crisp, reliable electronic shifting and stable chain management. With a 34T maximum low sprocket capacity, Shadow Plus clutch technology, and a direct mount design, this derailleur ensures smooth, quiet, and secure performance even over rough terrain.

Why you’ll like it

• Di2 electronic shifting – fast, precise, and consistent gear changes.
• Shadow Plus clutch – stabilizes the chain and reduces slap on gravel and trails.
• 34T maximum cassette compatibility – optimized for wide-range 2x gravel setups.
• Direct mount attachment – secure and clean installation to compatible frames.
• GRX-specific design – engineered for gravel and adventure riding.

What’s in the box

• 1 × Shimano GRX RD-RX815 Di2 Rear Derailleur (11-speed, Shadow Plus, direct mount)

Tech specs

Fit notes

• For Shimano GRX Di2 2x 11-speed drivetrains.
• Compatible with cassettes up to 34T max low sprocket.
• Requires Di2 shifters and wiring (sold separately).
• Direct mount design – confirm frame compatibility before installation.