Shimano Ultegra ST-R8170 Hydraulic Di2 Rear Left Lever And Caliper

Shimano Ultegra ST-R8170 Hydraulic Di2 Rear Left Lever and Caliper

Part of Shimano’s latest Ultegra 12-speed electronic groupset, the ST-R8170 Hydraulic Di2 Rear Left Lever and Caliper offers superlative performance, with wireless shifting and tireless braking.

This latest iteration of electronic Di2 is now cable-free at the shifter, as communication with the derailleur is wireless, powered by a small, replaceable battery. This not only reduces clutter but also makes cockpit changes simpler. The lever blades are easier to use with gloves on as they are larger than before, but they still operate in the same fashion, requiring just a light press to actuate. Inbuilt Bluetooth capability enables communication with phones and bike computers, and the app can be used to programme shift modes such as full or semi synchronised shifting where certain gear changes are automated to help keep the cadence exactly right.

Braking performance has also been improved, with Servo Wave technology adopted from Shimano’s mountain bike brakes. This gives better control and modulation, along with increased stopping power, increasing confidence on fast descents and technical roads. Pad clearance within the caliper is 10% better than before, so there is less chance of the pads catching the rotor, whilst the oversized ceramic pistons and finned pads provide fantastic heat management for fade-free use. The one-way internal fluid circuit and separate bleed port and valve screw make maintenance easier by simplifying the bleeding process.