The Shimano GRX ST-RX825 is the left-hand Dual Control Lever for fully wireless 2×12-speed Di2 gravel drivetrains. Combining precise hydraulic braking with instant electronic front shifting, it gives gravel riders confident control on rough terrain, switchbacks, and long mixed-surface descents — all from a single lever.

Highlights

• Fully wireless Di2 shifting: no wires, no cables through the bars — only the brake hose connects to the lever.
• Hydraulic disc braking: integrated master cylinder with SERVOWAVE technology for progressive, modulated stopping power.
• 2×12-speed left lever: controls the front derailleur in a double chainring GRX Di2 setup.
• Three programmable Di2 buttons: customise shift assignments, multi-shift, and satellite shifter pairing via E-TUBE PROJECT.
• Gravel-optimised hood shape: raised hood with ribbed texture and anti-slip coating, designed for flared drop handlebars.
• Reach and contact-point adjustment: independently tune lever blade position to suit your hand size and grip preference.
• Long battery life: two user-replaceable CR1632 coin cells per lever with an estimated 3.5–4 year lifespan.
• FRONT SHIFT NEXT compatible: enables semi-automatic front derailleur shifting in coordination with rear shifts.

Wireless Di2 Control

The ST-RX825 uses Shimano's fully wireless Di2 architecture, eliminating junction boxes and shift wires through the handlebar. Two user-replaceable CR1632 coin cells power the lever for an estimated 3.5–4 years between changes. Shifting response is instant and consistent regardless of cable stretch or mud ingress — ideally suited to gravel racing and endurance events where reliability is non-negotiable.

Hydraulic Braking & Ergonomics

The integrated hydraulic brake master cylinder delivers strong, progressive stopping power with fine modulation — critical for loose gravel and wet descents. SERVOWAVE technology increases pad travel speed early in the stroke for immediate brake engagement before transitioning to a more powerful, controlled feel. The lever blade features an independent reach adjuster and contact-point adjuster, allowing precise fit for different hand sizes. The hood body is shaped specifically for flared drop bars with a tactile, ribbed grip surface and anti-slip coating.

Customisation via E-TUBE PROJECT

Three programmable Di2 buttons on the lever allow shifting assignments and multi-shift functionality to be configured through the Shimano E-TUBE PROJECT app (iOS/Android). FRONT SHIFT NEXT functionality is supported, enabling the front derailleur to shift semi-automatically in coordination with rear shifts. The lever is also compatible with SW-RS801-S, SW-RS801-T, and SW-RS801-E satellite shifters for aero bar or alternative mounting positions.

Compatibility & Fit

The ST-RX825-L is a left-hand-only lever for 2-speed (double chainring) front setups in a 12-speed Shimano GRX Di2 drivetrain. It pairs with Shimano GRX Di2 front and rear derailleurs and is compatible with GRX hydraulic disc brake calipers using Shimano mineral oil. Not compatible with cable/mechanical derailleurs or wired Di2 junction box systems (EW-SD300/EW-WU111). Sold as a single left lever — right lever sold separately.