The Shimano GRX BL-RX825-L is a dedicated left-hand hydraulic disc brake lever built specifically for gravel riding. Designed to pair with the right-side ST-RX825 Di2 dual-control lever, it gives 1x gravel setups a clean, purpose-built brake solution — shaving 19.5 grams over the dual-control equivalent and keeping cable routing uncluttered.

Highlights

• SERVOWAVE braking: Fast initial pad take-up requires minimal lever travel to contact the rotor, with rapidly increasing power multiplication for confident, controlled stopping on gravel descents.
• Gravel-optimised ergonomics: Raised hoods with ribbed surface texture and anti-slip coating deliver secure grip whether riding on the hoods or in the drops, on rough terrain or in the wet.
• Flared bar compatibility: Hood shape and lever geometry are optimised for use with flared drop handlebars, the most popular choice for gravel and adventure riding.
• Tool-adjustable reach: Reach Adjust lets you dial in lever position to suit your hand size for maximum one-finger control and all-day comfort.
• Closed-clamp mounting: Secure, rattle-free installation on 23.8–24.2 mm handlebar diameters.
• Straight hose connection: Compatible with Shimano SM-BH90-JK-SS hydraulic hose for a clean, direct routing.

GRX Di2 Integration

The BL-RX825-L is engineered as part of Shimano's 12-speed GRX Di2 gravel groupset. It operates as a standalone brake lever with no shifting function, working seamlessly alongside the ST-RX825-R wireless Di2 dual-control lever. The system is also compatible with Shimano's full range of 12-speed wireless Di2 shifters, including Dura-Ace, Ultegra, 105 Di2, XTR, and Deore XT.

Hydraulic System

Shimano mineral oil provides consistent, fade-resistant braking performance across all conditions. The one-way bleeding process simplifies maintenance. The lever ships ready to pair with the BR-RX820 flat-mount caliper, compatible with SM-RT64, SM-RT70, and SM-RT800 rotors.

Compatibility & Fit

Left-hand brake lever only (Australian setup: left lever controls rear brake). Compatible with 12-speed Shimano wireless Di2 systems — GRX, Dura-Ace, Ultegra, 105 Di2, XTR, and Deore XT. Handlebar clamp diameter: 23.8–24.2 mm (standard drop/flared bar). Recommended hose: SM-BH90-JK-SS. Compatible caliper: BR-RX820. Compatible rotors: SM-RT64, SM-RT70, SM-RT800. Brake fluid: Shimano mineral oil.