Routing Di2 wires through integrated cockpits has always been the tedious part of electronic drivetrain installations. The ST-RX825 eliminates that headache entirely—these levers communicate wirelessly with the rear derailleur, leaving only the hydraulic brake hose to manage. A pair of CR1632 coin cell batteries powers each shifter with an expected lifespan of 1.5 to 2 years depending on how frequently you shift. When they eventually need replacement, you swap in fresh batteries rather than recharging, which simplifies maintenance on multi-day bikepacking trips where access to power may be limited.

Shimano redesigned the hood shape specifically for flared handlebars, which have become standard on gravel bikes. The transition from bar to hood follows a rounder, smoother profile that creates a larger contact surface and reduces pressure points during long days in the saddle. A ribbed texture across the hood top improves grip when conditions get rough, and the brake lever itself wears an anti-slip coating originally developed for Shimano's fishing gear—useful when your gloves are soaked or you are riding bare-handed in warm weather.

Three Di2 buttons per lever provide shifting and customization options through Shimano's E-Tube app. The two main buttons sit on the side in the traditional Shimano dual-control position, while a third button on the inside of the hood can be programmed for front derailleur shifts, satellite shifter functions, or compatible accessory control. Front Shift Next functionality allows any button to toggle the front derailleur between chainrings with a single press—up one press, down the next—which frees up button assignments for other uses. The levers also support Shimano's satellite shifters if you want additional shift points on the bar tops, drops, or aero extensions.... Read More