The Shimano GRX ST-RX820 and BR-RX820 J-Kit is everything you need to build a front disc brake corner on your gravel or mixed-terrain bike — pre-bled, ready to install, and built around Shimano's top-tier mechanical GRX 12-speed platform. The right-hand lever delivers crisp, cable-actuated 2x12-speed shifting while the integrated hydraulic master cylinder drives the BR-RX820 front caliper with progressive, powerful stopping force.

Highlights

• 2x12-speed mechanical shifting: Light, single-finger actuation for precise front and rear gear changes via Shimano's proven STI system.
• Hydraulic disc braking: Integrated master cylinder connects to the BR-RX820 2-piston flat-mount caliper for powerful, modulated stopping.
• Pre-bled J-Kit convenience: Lever and caliper arrive factory pre-bled with a 1000mm brake hose — no hydraulic setup required, just cut and connect.
• SERVO WAVE lever action: Fast initial pad contact with minimal lever travel, then progressive power multiplication for confident control on rough descents.
• Reach Adjust mechanism: Dial in the lever-to-bar distance to suit your hand size with a 3mm hex key — no tools required on the trail.
• Finned L05A resin pads: Ice Technologies-compatible finned pads dissipate heat during long descents for consistent braking performance.
• One-Way Bleeding system: Streamlined oil circuit prevents air ingress during bleeding for faster, cleaner maintenance intervals.
• Gravel-optimised ergonomics: Anti-slip textured lever surface and reduced-pressure hood shape keep hands comfortable and controlled all day in the drops.
• Mineral oil hydraulic system: Easy to source, safe to handle, and straightforward to service.

GRX Shift-Brake Technology

The ST-RX820-R integrates Shimano's STI (Shimano Total Integration) shift-brake design with ergonomics tuned specifically for gravel and mixed-terrain riding. The textured, anti-slip brake lever surface maintains control on rough descents, while the ergonomic hood shape reduces palm pressure during long days in the drops. The shift mechanism draws on Shimano's mountain bike platform for robustness — reliable actuation is maintained in mud, wet conditions, and rough terrain where gravel riding demands it.

BR-RX820 Hydraulic Caliper

The BR-RX820 2-piston flat-mount caliper delivers a tighter pad clearance tolerance and a more accessible bleed port compared to previous GRX generations. The One-Way Bleeding system streamlines the oil route to prevent air entering the circuit, making bleed intervals faster than ever. Finned L05A resin pads are included to assist heat management on longer technical descents. The flat-mount bracket supports 140mm or 160mm rotors and ships assembled for 160mm.

Compatibility & Fit

This right-hand lever provides 2x12-speed rear mechanical shifting and (in standard Australian setup) controls the front brake. Compatible rear derailleurs: RD-RX820 (2x12) and RD-RX822 (1x12). Compatible front derailleurs: FD-RX820 and FD-R7100. Sub-brake lever compatibility: BL-RX812. Brake hose: SM-BH90-JK-SSR (1000mm, included). Flat-mount caliper bracket supports 140mm or 160mm rotors; shipped assembled for 160mm. Rotor and adapter sold separately — Shimano recommends the RT-CL800 rotor. Handlebar clamp diameter: 23.8–24.2mm. Hydraulic fluid: Shimano mineral oil.