The Shimano Ultegra ST-R8170-L delivers wireless Di2 electronic shifting and precision hydraulic braking in a single ergonomic road lever. As part of the R8100 groupset, it brings Dura-Ace-level technology within reach of every serious road rider — with a redesigned raised hood profile, refined Servo Wave brake modulation, and a fully wireless Di2 platform that eliminates junction box wiring at the lever.

Highlights

• Wireless Di2 shifting: No junction box or wiring needed at the lever — pairs directly with R8100 and R9200 Di2 derailleurs for clean, responsive electronic shifting.
• Servo Wave brake technology: Variable leverage throughout the lever stroke delivers rapid pad engagement followed by smooth, progressive modulation for confident control in all conditions.
• Reach and free-stroke adjust: Bolt-actuated reach adjustment (16.4 mm range) and free-stroke adjustment let you dial the lever position precisely to your hand size and preference.
• Long-life CR1632 battery: User-replaceable coin cell battery rated for 1.5–2 years of typical use, with a simple swap requiring no tools.
• E-Tube Project compatible: Customise shift modes (Synchro Shift, Semi-Synchro Shift, Multi-Shift), button assignment, and shift speed via the Shimano E-Tube Project app.
• Satellite shifter ready: One SD300 port supports an optional satellite shifter (SW-RS801 or SW-RS802) for additional shift points on the tops or drops.
• Premium materials: Aluminium brake lever blade paired with a carbon fibre reinforced polymer (CFRP) body for strength and reduced weight.

Design and Ergonomics

The R8170 STI lever features a raised hood profile with increased material between the lever and handlebar, offering a more natural and secure grip position when riding on the hoods. The smooth outer surface provides a consistent feel in all weather conditions. The brake lever's variable leverage ratio — the Servo Wave mechanism — changes mechanical advantage through the stroke, giving a light initial pull that becomes progressively firmer as the pads contact the rotor.

Wireless Di2 Platform

The ST-R8170 operates on Shimano's latest wireless Di2 platform, shared with the flagship Dura-Ace R9200 groupset. Shifting signals are transmitted wirelessly to the front and rear derailleurs, and the E-Tube Project app enables full customisation of shift behaviour, firmware updates, and system diagnostics from a smartphone. The lever also retains a wired Di2 connection option for setups requiring it.

Compatibility & Fit

Designed for 2x12-speed electronic road groupsets. Compatible with Shimano Ultegra R8100 Di2 and Dura-Ace R9200 Di2 components. Fits road handlebars with a clamp diameter of 23.8–24.2 mm. Hydraulic brake system requires Shimano mineral oil and is designed to pair with the BR-R8170 flat mount calliper. Brake hose: SM-BH90-JK-SSR (straight J-Kit joint, sold separately). In Australian brake setup, the left lever controls the rear brake.