Take your gravel build to the next level with this complete Shimano GRX Di2 hydraulic disc brake kit, pairing the ST-RX815 right-hand electronic dual control lever with the BR-RX820 flat-mount caliper. You get crisp, button-actuated Di2 shifting and powerful hydraulic braking in a single pre-bled unit — ready to fit, trim, and ride.

Highlights

• Di2 electronic 11-speed shifting: light, precise button presses replace mechanical cable throws for faster, more repeatable gear changes on mixed terrain.
• Gravel-specific ergonomics: the raised hood head and recessed finger notch keep your hands firmly placed when the track gets rough and unpredictable.
• SERVO WAVE actuation: pads reach the rotor quickly with minimal lever travel, delivering a responsive initial bite and excellent braking modulation on long descents.
• BR-RX820 flat-mount caliper: wider 2-piston design with 10% more pad clearance for reduced brake noise and easier maintenance.
• L05A resin finned pads with ICE Technologies: aluminium cooling fins dissipate heat build-up during extended descents, protecting pad life and maintaining consistent stopping power.
• Pre-bled and ready to install: filled with Shimano mineral oil and supplied with hydraulic hose; simply cut to length and connect during installation.
• Adjustable reach: tooled reach adjust suits a range of hand sizes and riding positions without additional parts.

Electronic shifting built for gravel

The ST-RX815 is Shimano's GRX Di2 dual control lever, purpose-built for gravel and mixed-surface riding. Shifts are made with a light button press — no cable tension, no throw — giving you consistent gear changes whether you're on smooth tarmac or holding on through a rutted descent. Three programmable switches (two on the lever body, one on the hood top) can also be mapped to operate compatible Di2 or third-party devices. Two E-tube ports allow integration with a full Di2 groupset.

Hydraulic braking power

The BR-RX820 caliper is the next generation of Shimano's GRX gravel braking. Its flat-mount, 2-piston design sits low and light on the frame while delivering strong, consistent stopping force. The wider pad-to-rotor clearance reduces rubbing and noise, and the L05A resin pads with aluminium cooling fins manage heat through Shimano's ICE Technologies — keeping brake performance stable even on long alpine descents. SERVO WAVE actuation ensures fast pad engagement so you're never waiting for the bite point.

Compatibility & fit

Designed for Shimano GRX and road Di2 11-speed electronic groupsets. This is the right-hand lever, which in a 2×11 Di2 setup operates the rear derailleur for electronic shifting. Following the Australian convention, the right lever operates the front brake — so this kit includes the front flat-mount caliper. Caliper uses the flat-mount disc brake standard; a bracket adapter is required for post-mount or thru-axle frames not already flat-mount ready. Compatible brake rotors (e.g. SM-RT800) are sold separately. Di2 junction box, battery, and wiring are sold separately.