The Shimano Ultegra ST-R8170 right lever brings wireless Di2 electronic shifting and hydraulic disc braking together in a single precision-engineered control unit. Built for road cyclists who demand Dura-Ace performance at an accessible price point, the R8100 generation introduces a completely re-engineered platform with cleaner routing, ergonomic refinements, and deep customisation via the E-Tube Project app.

Highlights

• Wireless Di2 shifting — no visible shift cables, simplified installation
• Shimano Servo Wave technology for progressive, modular hydraulic disc brake modulation
• 2×12-speed electronic rear shifting (right lever)
• Three programmable switches per lever for satellite shifter or custom function mapping
• Reach adjustment range of 16.4 mm to fit a wide range of hand sizes
• Hood extended 4.6 mm versus the previous R8070 generation for improved ergonomics
• CR1632 coin-cell battery with 1.5–2 year estimated service life, user-replaceable
• Synchro Shift and Semi-Synchro Shift modes supported
• Carbon fibre-reinforced polymer (CFRP) lever blade for low weight
• Mineral oil hydraulic system — predictable feel and easy servicing

Wireless Di2 Technology

The ST-R8170 communicates wirelessly with Shimano's R8100 and R9200 electronic derailleurs over Bluetooth Low Energy, eliminating the shift wire routing that complicated earlier Di2 installations. The lever still accepts an optional EW-SD300 wired connection for satellite shifters (SW-RS801 bar-top, SW-RS802 drops), and the full system can be configured and monitored through the Shimano E-Tube Project app. Synchro Shift mode automates front/rear derailleur coordination for seamless 1×-style cross-range shifting on a 2× drivetrain.

Servo Wave Hydraulic Braking

Shimano's Servo Wave lever geometry varies the mechanical advantage across the brake stroke, delivering light initial lever pull to take up pad clearance then increased power as the pads bite the rotor. The result is a progressive, confidence-inspiring feel that gives the rider fine-grained control at the top of the stroke and maximum stopping power deeper in. The system uses Shimano mineral oil — less hygroscopic than DOT fluid — for long-term consistent performance and straightforward maintenance.

Compatibility & Fit

The ST-R8170-R is the right-hand lever only — it controls rear shifting and, in the Australian convention, the front brake. A separate left lever (ST-R8170-L) is required to complete a paired set. Compatible derailleurs: RD-R8150 / RD-R9250 (rear), FD-R8150 / FD-R9250 (front). Compatible calipers: BR-R8170, BR-R9270 (flat mount). Hydraulic hose kits (SM-BH90-JK-SSR) are sold separately. Satellite shifters SW-RS801 and SW-RS802 are supported. The BT-DN300 Di2 battery and junction unit are required for system power. Not compatible with mechanical or non-R8100/R9200 Di2 derailleurs.