The Shimano GRX ST-RX815-R combines Di2 electronic shifting and hydraulic disc braking in a single right-hand lever, purpose-built for gravel and mixed-terrain riding. Designed to complement the GRX Di2 11-speed groupset, it delivers precise, one-finger gear changes and powerful, progressive braking through terrain that road-focused components can't handle.

Highlights

• Shimano Servo Wave mechanism: Delivers powerful, modulated braking with less lever effort — ideal for long descents and technical terrain.
• Tooled reach adjust: Dial in the lever-to-bar distance to suit your hand size and riding preference, without swapping parts.
• Free stroke adjust: Fine-tune the initial lever travel before braking engagement kicks in.
• Two E-tube ports: Integrate seamlessly into a Di2 electronic system, with port flexibility for junction cables and satellite shifters.
• Gravel-specific ergonomics: Raised brake axis, anti-slip textured hood, and recessed finger notch keep hands locked in on rough roads.
• Mineral oil hydraulic system: Uses Shimano mineral oil — non-corrosive, non-hygroscopic, and safer to handle than DOT fluid.
• Electronic shift precision: Di2 actuation means consistent, instant gear changes with no cable stretch or mechanical fatigue.

Design for Gravel

Shimano developed the GRX lever geometry specifically around the demands of off-road and gravel riding. The brake axis sits 18 mm higher than on road levers, reducing wrist strain in the drops on rough terrain. The raised hood head prevents hand misalignment, while anti-slip ridges provide confident grip through the roughest sections. The result is a lever that encourages riders to stay in the drops and brake with control, not survival instinct.

Di2 Integration

As a Di2 component, the ST-RX815-R operates via Shimano's E-tube network. Each lever carries two E-tube ports, allowing flexible wiring in both front and rear configurations. The shift buttons and functions are fully programmable via the Shimano E-TUBE PROJECT app, and the levers are compatible with Shimano's D-FLY wireless unit for ANT+/Bluetooth integration with cycling computers and apps.

Compatibility & Fit

The ST-RX815-R is a right-hand lever for 11-speed GRX Di2 systems. It is designed for use with Shimano hydraulic disc brake callipers (such as the BR-RX810) and SM-BH90-JK-SSR brake hose. Brake fluid: Shimano mineral oil. Compatible with 11-speed road Di2 rear derailleurs. Recommended cassettes for 2x11: CS-R8000 (11-30t/11-32t) or CS-HG800-11 (11-34t); for 1x11: CS-M8000 (11-40t or 11-42t). Recommended rotor: SM-RT800 (sold separately). Clamp inner diameter: 23.8–24.2 mm (drop bar). This listing is for the right-hand lever only; the left-hand lever (ST-RX815-L) is sold separately.