The Shimano ST-RX815-L is the left-hand Dual Control Lever from the GRX Di2 groupset — Shimano's purpose-built electronic drivetrain for gravel and adventure riding. Combining precise Di2 electronic shifting with a hydraulic disc brake master cylinder in a single ergonomic unit, it delivers confident braking and effortless 2x11-speed front shifting on the roughest terrain.

Highlights

• SERVOWAVE braking: A raised brake lever axis and curved lever profile move the pads quickly at initial pull, then slow for fine modulation — delivering powerful, controlled stopping on loose or technical surfaces.
• Di2 electronic precision: Single-button front shifting via Shimano Di2 electronics eliminates cable tension drift and provides positive, repeatable engagement regardless of conditions.
• Synchronized Shifting: Pairs with GRX Di2 derailleurs for automatic front/rear compensation, keeping the chain in the optimal line and reducing cross-chaining.
• Gravel-optimised ergonomics: A raised hood head and recessed finger notch prevent hand slippage on rough terrain, while the anti-slip textured surface maintains grip through extended gravel stages.
• Reach adjust: Lever reach is adjustable at the top of the lever body to suit a wide range of hand sizes and riding preferences.
• Two E-tube ports: Each lever features two E-tube ports for flexible Di2 wiring routing options.
• Mineral oil hydraulics: Uses Shimano mineral oil for stable, non-corrosive braking performance.

GRX Di2 — Built for Gravel

The GRX Di2 groupset is Shimano's answer to the unique demands of gravel and mixed-terrain cycling. The ST-RX815-L brings MTB-derived technologies — SERVOWAVE lever mechanics and rugged hood ergonomics — into a drop-bar package optimised for long days off the tarmac. The Di2 electronic system ensures consistent, accurate shifting performance even when the bars are vibrating over gravel, mud, or corrugated dirt roads.

Programmable Inputs

All shift buttons on the ST-RX815-L are programmable via Shimano's E-Tube Project software, allowing riders to customise shifting assignments to suit their preferred riding style. An additional inner-hood button above the thumb rest provides a third input point, expanding programming options for multi-shift, sprint mode, or synchronised shifting activation.

Compatibility & Fit

The ST-RX815-L is a left-hand lever for 2x11-speed Di2 configurations. It is compatible with Shimano Road and GRX 11-speed Di2 derailleurs. Hydraulic disc brake only — not compatible with cable-actuated or rim brake systems. Designed for standard drop-bar handlebar diameters of 23.8–24.2 mm. Uses Shimano mineral oil hydraulic fluid. Pairs with Shimano SM-BH90 or SM-BH59 brake hoses. Di2 wiring connects via standard E-tube plug connectors.