The Shimano GRX ST-RX820 Dual Control Lever paired with the BR-RX820 rear hydraulic disc brake caliper delivers top-tier gravel performance in a single ergonomic unit. Combining mechanical 12-speed shifting with confident hydraulic braking, this left-hand lever set is engineered from the ground up for mixed-terrain and gravel cycling. In Australian riding convention the left lever controls the rear brake — the primary brake — making this kit the centrepiece of your GRX stopping power.

Highlights

• Mechanical 12-speed shifting: smooth, precise cable actuation compatible with the full GRX RX820 drivetrain.
• SERVO Wave braking: rapid initial pad engagement followed by progressive force build for confident, controllable stopping on loose gravel.
• BR-RX820 flat-mount caliper: 2-piston hydraulic caliper with 10% wider pad clearance than the previous generation to reduce disc rub and brake noise.
• Anti-slip lever surface: textured coating maintains grip in wet and muddy conditions for secure braking at all times.
• Reach adjust mechanism: dial in lever distance to suit hand size, glove thickness, and riding style.
• Gravel-optimised ergonomics: lever body shaped for flared handlebars, reducing palm pressure on long efforts.
• Mineral oil hydraulic system: consistent, fade-resistant braking with Shimano's closed hydraulic fluid — gentler on paintwork and skin than DOT fluid.
• L05A finned resin pads included: aluminium fins dissipate heat on sustained descents.
• 1700mm brake hose pre-installed: ready for rear caliper routing on standard frames.

SERVO Wave Technology

Shimano's SERVO Wave lever action reduces initial pad travel so the pads contact the rotor quickly, then multiplies braking force progressively through the remainder of the stroke. The result is fast, predictable pad engagement with genuine modulation — critical when managing speed on loose gravel descents or threading narrow lines on mixed terrain.

Gravel-Optimised Ergonomics

The ST-RX820 lever body is engineered for flared handlebars that define modern gravel bikes. Textured anti-slip surfaces on the tops and lever blade maintain secure purchase even in mud and rain. The reach-adjust mechanism lets riders set the exact lever distance for their hand size without needing tools on the road. At 283g the lever is competitive for a mechanical hydraulic unit at this specification level.

BR-RX820 Hydraulic Caliper

The matched BR-RX820 is a 2-piston flat-mount caliper using Shimano Mineral Oil. An Allen-key bleed port simplifies home servicing. Pad clearance is increased by 10% over the previous generation, reducing noise and rub on rough terrain. The caliper ships with L05A finned resin pads installed and weighs 136g (rear). Recommended rotor is the RT-CL800.

Compatibility & Fit

Left-hand lever set — ST-RX820-L shift/brake lever with BR-RX820 rear hydraulic disc brake caliper and 1700mm SM-BH90-JK-SSR brake hose. Compatible with Shimano GRX 12-speed mechanical drivetrain components including RD-RX820 (2×12) and RD-RX822 (1×12) rear derailleurs. Also compatible with Shimano 12-speed road mechanical rear derailleurs. Requires a flat-mount disc brake frame rear mount. Hydraulic fluid: Shimano Mineral Oil. Rotor sold separately; compatible with 140mm and 160mm flat-mount rotors (adapters required for 160mm flat mount on rear). Pair with ST-RX820-R for a complete GRX mechanical Dual Control Lever setup.