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.
Features
- High-performance Ultegra Wireless hydraulic Servo Wave disc brake Di2 STIs give control, modulation and power with minimal effort in all riding conditions
- Operates front derailleur and rear brake
- Wireless connectivity to the front and rear derailleurs for effortless trouble-free gear shifts
- With Di2 technology shifting is easy and precise - just a light touch, as soft as a mouse click, is sufficient for the front or rear derailleur to instantaneously select the correct gear
- Full and semi synchronised shifting programable
- Synchro shift compatible meaning a single shifter can control both front and rear shifting which can be fully custom tuned to your riding preferences
- Semi synchronised shifting means when a front shift is made the rear mech will automatically correct to the appropriate ratio
- Simply pressing tactile buttons allows effortless and comfortable shifting even when your hands are cold
- Drop bar STI with shift buttons located in a near identical place to the positions you'd assume shifting using a mechanical Shimano STI
- Hydraulic brake lever with Servo Wave provides excellent stopping power with less effort especially from the hood position
- Hydraulic reservoir tank provides pad to rotor clearance auto-adjust maintaining braking performance during pad wear
- Finely tuneable reach adjusters for the levers enable custom fitment for all hands
- Levers use CR1632 batteries which last for approximately 1.5-2 years
- Front wheel use for flat mount forks
- Oversized 22mm ceramic pistons optimised for heat insulation, lightweight and stiffness
- Opposed 2-piston design reduces leading effect and optimal pad wear increases braking control
- Increased pad to rotor clearance reduces the chance of rotor drag
- Direct flat mount and open design allows easy and quick wheel replacement
- Forged calliper design is lightweight and rigid
- One-way internal fluid circuit makes bleeding easy
- Mineral oil brake fluid is non-corrosive and less hazardous than conventional hydraulic brake fluid
- Shim-less mounting bracket allows for quick installation and setting up
- Recommended for use with Ice Tech FREEZA Center Lock SM-MT800 rotors for optimum braking performance
- Comes complete with resin compound aluminium radiation fin pad further improves heat dissipation reducing brake surface temperature by 50°C
- Inline hose routing for low profile design
- Separate bleed port and valve screw for improved bleeding process
- Kit contains bled ST-R8170 STI, BR-R8170 flat mount brake callipers with pads, hoses and mineral oil (without rotors or adapters)
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