Transform your gravel bike into a fully electronic, dropper-ready machine with the Shimano GRX RX817 1x11 Di2 + Dropper Gravel Upgrade Kit. This comprehensive kit combines GRX Di2 electronic shifting with Shimano's purpose-built gravel ergonomics, Shadow RD+ chain stabilisation, and programmable lever controls — giving you precise, reliable performance across mixed terrain, from smooth chip-seal to rough gravel roads.

Highlights

• GRX Di2 ST-RX815 hydraulic shift/brake levers — electronic shifting with integrated hydraulic disc braking
• RD-RX817-GS Shadow RD+ rear derailleur — electronic 1x11 rear derailleur for cassettes up to 42T
• BR-RX810 flat-mount hydraulic disc calipers with IceTech pad compatibility
• FC-RX810-1 Hollowtech II crankset — 1x11 gravel-specific with narrow-wide chainring (40T or 42T)
• 11-speed cassette, CN-HG701-11 chain, and Shimano RT800 disc rotors included
• Dropper post lever integration — left lever activates a compatible dropper seatpost mechanically
• Programmable Di2 satellite switches on levers for third-party device control (lights, computers)

GRX Di2 Electronic Shifting

The GRX Di2 system brings Shimano's electronic precision to gravel riding. The ST-RX815 dual-control levers feature gravel-optimised ergonomics: a raised hood head that prevents misalignment, a recessed finger notch to stop the hand slipping upward, and anti-slip textured rubber for control on rough surfaces. Each lever has three programmable satellite switch ports, allowing you to operate compatible lights, computers, or other devices without taking your hands off the bars. The RD-RX817-GS rear derailleur provides instant, consistent shifting across an 11-42T cassette range, with a 31T chain wrap capacity suited to the wide-range gearing gravel demands.

Shadow RD+ Chain Stabilisation

The RD-RX817 rear derailleur uses Shimano's Shadow RD+ clutch mechanism to dampen chain movement over rough ground, preventing chain slap and reducing the risk of drops. An on/off switch next to the upper pulley lets you disengage the clutch when loading or unloading the bike. The low-profile, compact derailleur body sits close to the frame to minimise the risk of impact damage on rocky trails.

Braking & Crankset

BR-RX810 flat-mount hydraulic disc calipers deliver powerful, modulated stopping with Shimano's SERVOWAVE lever geometry — the rotary axle is positioned to improve initial bite feel while maintaining smooth modulation under hard braking. Calipers are compatible with IceTech rotors for improved heat management on long descents. The FC-RX810-1 Hollowtech II crankset is purpose-built for 1x gravel drivetrains: a 110 BCD 4-bolt spider accepts aftermarket chainrings, and the narrow-wide tooth profile retains the chain without a front derailleur. Available in 170mm, 172.5mm, and 175mm crank lengths with 40T or 42T chainrings.

Compatibility & Fit

Designed for drop-bar gravel bikes with flat-mount disc brake tabs and internal Di2 wire routing. The ST-RX815 levers clamp onto 23.8–24.2mm drop bar tubes. The FC-RX810-1 crankset uses Shimano Hollowtech II bottom bracket interface (BB not included — specify threaded or press-fit to suit your frame). The RD-RX817-GS is compatible with 11-40T and 11-42T Shimano HG-EV cassettes. Kit includes Di2 wiring components (battery, junction, and E-tube wires) — wire lengths vary by frame; confirm internal routing dimensions before ordering. A compatible dropper seatpost (sold separately) is required for dropper integration.