Sold individually, as left or right, these Ultegra ST-R8170 Dual Control Levers are sold with the hydraulic disc brake caliper and hose kit. With R8100-series 12-speed, Shimano has dropped cable-actuated shifting so the only option is the new Di2-equipped R8170 lever system for disc brakes (or the R8150 for rim brakes). There have been many changes to the Di2 system for this 12-speed group and the dual control levers carry significant differences from the R8070 11-speed models. All-new lever ergonomics on the dual control levers bring new levels of rider comfort and control to road cycling. With the fastest wireless shifting available and even more precise brake modulation, these levers compete with the Dura-Ace version as the best Shimano has ever offered.

Yes, the R8100-series features wireless shifting from the shift levers to the derailleurs via a battery system. The shifters carry a coin cell battery which powers a dedicated, secure low power signal to the smart battery. No wires are required with the R8170 Dual Control Levers, but you do have the option of wiring them if you prefer. The front and rear derailleurs are each directly wired to the new 3-wiring port equipped BT-DN300 battery with new SD300 Di2 wires, which are thinner and lighter overall. The third port is available for a potential fully wired system from the shifters back. There is no junction box required at or near the levers, as that system has been moved directly into the body of the rear derailleur. Not only is the system faster, lighter and more efficient, it also eliminates complicated and challenging fully wired set-ups through today's fully integrated internal wiring that runs through bar to stem and onto fork then into frame.

Don't sleep on the ergonomic improvements. The lever bodies have a flat section that is 4.6mm longer for better support of the hand and body weight, but also have a taller peak, again for better grip and control. These two aspects were driven by cyclist feedback, from pros to everyday enthusiasts. The same can be said for the larger and more defined shift buttons. The levers are still compatible with new satellite shift buttons that do wire directly into the body. The new hood design has excellent cushion and grip texture, complementing the overall feel and shape of the lever bodies. The third, peak-top control switch is carried over from the previous generation, and this accessory button can be set-up to control compatible cycling compatible head units. Di2 set-up, shift and accessory button functions, battery level, and troubleshooting can all be done through the current generation E-Tube Project app via BLE communication available for iOS and Android smartphones, as well as the PC version.

On the hydraulic disc braking front, the R8170 levers now feature Shimano's SERVO WAVE ACTION brake technology. Each brake lever delivers modulation and control like never before thanks a new shape and leverage point. The brake levers themselves still feature manual Reach Adjust at 16.4mm total range so people with shorter fingers or smaller hands can more reasonably control the brake lever pull while hands are in the drops or sitting on the lever tops. Overall the action is lighter and smoother, but moderates the power with the aforementioned modulation for a more defined, effective braking action throughout the lever stroke. The overall braking experience is also enhanced at the new caliper as well as the new Ice Technologies disc rotor design.

For the Flat Mount calipers, which are compatible with 140 or 160 mm disc rotors depending on hardware set-up, updated 2-piece construction ensures lighter weight and greater rigidity, with a lower profile design. The BR-R8170 caliper drops weight while also providing increased pad clearance (10%) by decreasing the chance of rotor rub, ensuring a quieter ride. Shimano has also developed a new One Way Bleeding process that further simplifies maintenance and set-up while improving consistency and saving time. The caliper comes with the finned brake pad set that Shimano developed with Ice Technologies that effectively uses the fins as a radiator to release heat from the pad rotor surface as quickly as possible. This is the L03A Resin version of that pad and the most commonly selected option for all-around road cycling. You get all the appropriate hardware and installation pieces for the caliper- specific to the front or rear option. Shimano supplies their SM-BH90-JK-SSR hydraulic hose kit for the Mineral Oil based hydraulic system.