Electronic shifting on a gravel bike eliminates cable stretch and contamination concerns that come with riding through mud, sand, and whatever else the route throws at you. The Shimano GRX ST-RX815 brings wired Di2 functionality to gravel-specific ergonomics, giving you the same shift internals as Ultegra Di2 wrapped in a lever shape designed for rough terrain. Shifting happens with a light button press that requires about 2mm of movement, leaving you free to focus on line choice rather than lever manipulation when things get technical. The distinguishable click between upshift and downshift paddles lets you confirm your action by feel without looking down.

The hood shape differs significantly from road Di2 levers. Shimano raised the hood peak and added a more dramatic slope that matches how gravel riders typically position their hands during long rides on mixed surfaces. A recessed finger notch on the front prevents your hand from sliding forward under braking, while textured anti-slip surfaces on both the hood body and brake lever blade help maintain grip when vibration and impacts try to shake you loose. The higher brake lever axis positions the pivot point for more natural leverage whether you're braking from the hoods or the drops, reducing fatigue on long descents where you're constantly modulating speed.

Braking uses Servo Wave technology through a hydraulic system running Shimano mineral oil. The lever moves brake pads toward the rotor quickly on initial pull, then the leverage ratio increases for modulated control once contact happens. This matters on loose surfaces where grabbing too much brake too quickly causes skids. Reach adjustment lets you position the lever blade closer to the bar for smaller hands. These levers work with BR-RX810 flat mount calipers and connect via SM-BH90-JK-SSR hose kits, though caliper and hose need to be purchased separately as this is the lever-only option.... Read More