The Shimano Ultegra ST-R8170 is the right-hand Di2 STI lever from the R8100 groupset — bringing wireless electronic shifting and hydraulic disc braking together in one refined package. Trickle-down technology from Dura-Ace R9200 means every feature found here was race-proven at the top level first. Whether you're training hard or racing, the ST-R8170 delivers instant, repeatable gear changes and progressive stopping power without ever lifting your hands from the bars.

Highlights

• Wireless Di2 shifting: Bluetooth Low Energy connects the levers to the derailleurs via the BT-DN300 battery unit — no lever wiring required.
• SERVO WAVE braking: Variable leverage ratio brings pads to the rotor quickly with light effort, then multiplies power at the end of the stroke for precise, confident modulation.
• CFRP lever blade: Carbon fibre-reinforced polymer keeps the blade lightweight and stiff for crisp, direct brake feel.
• User-replaceable CR1632 battery: Estimated 1.5–2 year lifespan under normal use; swaps in under a minute without tools.
• Three programmable switches: Each lever has three customisable inputs via the Shimano E-Tube Project app (iOS/Android) for Synchro Shift, multi-shift, or custom functions.
• Reach and free-stroke adjust: 16.4 mm of reach adjustment plus free-stroke adjustment allows a personalised brake feel for any hand size.
• Satellite shifter port: One SD300 port per lever — compatible with SW-RS801 (tops) and SW-RS802 (drops) bar-end switches for extended control positions.
• Redesigned hood: Extended 4.6 mm longer than the previous R8070 generation for improved grip and all-day comfort.

SERVO WAVE Braking

Shimano's SERVO WAVE mechanism varies the mechanical advantage of the lever throughout its travel. The initial pull rapidly closes the gap between pads and rotor with minimal effort, while the final stroke delivers multiplied power for sure, controlled stops. Paired with the BR-R8170 flat-mount caliper and Shimano Mineral Oil, the system provides class-leading modulation in all conditions and weather.

Wireless Di2 Platform

The R8100 Di2 system uses Bluetooth Low Energy to communicate wirelessly between the levers and derailleurs. The BT-DN300 junction battery unit provides power to the derailleurs — the levers run independently on their own CR1632 cells. Firmware updates, Synchro Shift programming, and multi-shift customisation are all handled through the Shimano E-Tube Project app. This is the right-hand lever, which controls rear shifting in a standard Australian road setup (right lever = front brake, rear derailleur shifting).

Compatibility & Fit

Designed for Shimano Ultegra R8100 and Dura-Ace R9200 Di2 groupsets (12-speed). Compatible with BR-R8170 hydraulic disc brake calipers (sold separately). Requires SM-BH90-JK-SSR hydraulic hose (sold separately) and Shimano Mineral Oil — do not use DOT fluid. Clamp diameter suits standard 23.8–24.2 mm drop handlebars. Not compatible with mechanical shifting, rim-brake systems, or previous-generation Di2 (R8070/R8050). This listing is for the right lever only — the left lever (ST-R8170-L) is sold separately.