The Shimano Ultegra ST-R8170 is the right-hand Dual Control Lever at the heart of the R8100 Ultegra Di2 groupset — bringing wireless 12-speed electronic shifting and precision hydraulic disc braking together in one refined, ergonomic package. Developed alongside Dura-Ace R9200, it delivers race-proven performance at an accessible price point, with clean cockpit aesthetics and deep customisation through the E-Tube Project app.

Highlights

• Wireless Di2 12-speed electronic shifting — no wire between lever and derailleur for a clean, aerodynamic cockpit
• SERVO WAVE hydraulic braking technology for faster initial pad contact and progressive, intuitive modulation
• Raised hood peak and redesigned ergonomic profile for comfort in every riding position
• Reach and free stroke adjustment to suit different hand sizes and braking preferences
• SD300 satellite shifter port — add bar-end or climbing shifters without extra wiring
• User-replaceable CR1632 coin cell battery with 1.5–2 year typical life
• Fully compatible with Shimano E-Tube Project app for custom button mapping, shift speed, and Synchro/Semi-Synchro shift modes
• Weight: approximately 196 g (right lever only)

Wireless Di2 Shifting

The ST-R8170 uses Shimano's latest wireless Di2 platform, transmitting shift commands electronically without a physical cable between the lever and rear derailleur. The result is a clutter-free bar with no housing ports or junction boxes on the cockpit. Wired connectivity remains supported for builds where it's preferred, giving full flexibility. The lever's shift buttons can be remapped and speed-tuned via the E-Tube Project app (v4.0.0+), and automatic Synchro and Semi-Synchro shifting modes allow the front derailleur to trim automatically as you move through the cassette.

SERVO WAVE Hydraulic Braking

Shimano's SERVO WAVE mechanism varies the mechanical leverage ratio across the lever stroke — providing a wider initial sweep for fast pad engagement, then shifting to a stiffer ratio for powerful, controlled deceleration. The expanded braking control area gives more nuanced modulation at the fingertips, particularly useful when descending or navigating technical terrain. Mineral oil hydraulics are used throughout the Ultegra R8100 system, offering consistent performance and easy maintenance. The lever is pre-bled and compatible with the SM-BH90-JK-SSR hose kit and BR-R8170 caliper.

Ergonomics & Adjustability

The reshaped hood features a raised peak that improves grip security whether riding on the tops, hoods, or in the drops. Reach adjustment allows the lever blade to be positioned closer to the bar for smaller hands, while free stroke adjustment controls how much lever travel occurs before the brake pads make contact — letting each rider dial in the feel they prefer without tools at the roadside.

Compatibility & Fit

The ST-R8170 right lever is designed for Shimano Road Di2 12-speed drivetrains and is compatible with the full Ultegra R8100 and Dura-Ace R9200 groupset components. It mounts to standard 23.8–24.2 mm drop handlebars. Recommended brake caliper: BR-R8170. Recommended hose: SM-BH90-JK-SSR. Uses Shimano Mineral Oil hydraulic fluid. Satellite shifter port (SD300) enables optional climbing or bar-end shifters. Not compatible with mechanical shifting or rim brake systems.