Shimano hasn’t been sitting idle as component rival SRAM developed and debuted its HyroR hydraulic brake systems. The Japanese brand announced on Monday that it, too, would jump into the game with a new 11-speed, disc-brake-ready Ultegra 6870 Di2 group.
R785 hydraulic and electronic system
Hydraulic electronic shift levers are a new approach for Shimano. Formula has had its Di2-compatible brake levers on the market since Sea Otter last spring, so the basic design is not totally unprecedented.
Shimano’s first road hydraulic option will use the ICE-Tech technology developed for its mountain bike brakes. As the name suggests, ICE-Tech is focused on heat-management, the Achilles heel of disc systems and the primary concern with any move to discs on the road. The ICE-Tech rotors that have the FREEZA fins inside of the rotor, which add surface area to the rotor without raising the rotor size, and the calipers feature fins to help cool the brake pads. The technology has proved to be extremely effective on the dirt.
Of course, in Shimano-fashion the SM-RT99 rotors will be Centerlock and Shimano is launching a road disc wheelset, the WH-RX31, which completely does away with standard rim brake tracks. The rotors will be available in 140 and 160mm options.
The hydraulic disc caliper, BR-785 is a dual-piston design that’s been tuned for road use, improving modulation and decreasing weight.
The ST-R785 levers offer the full range of E-tube compatible shift options, including Shimano’s sprint and climbing shifters and the ability to adjust shift speed and shift count. The new system is easily upgradeable with firmware updates over time.
Ultegra Di2 6870
The new Ultegra Di2 6870 groupset brings 11-speed electronic shifting down to a more reasonable price point, while maintaining all of the functionality and most of the performance of the top-tier Dura-Ace group.
Both the new 6870 Ultegra Di2 and the new hydraulic R785 shift levers use Shimano’s E-Tube software, which allows the rider to update the firmware for different drivetrains, multi-shift styles, shift counts, and speed.
The 6870 and R785 groups are cross-compatible with both 10-speed 6770 components as well as the new Dura-Ace 9070 components, but no Dura-Ace 7870, as it does not use the E-Tube software. This means riders with 10-speed 6770 have the option to upgrade to 11-speed without having to replace their ST-6770 levers or brake calipers.
The whole group drops 126 grams compared to the 10-speed Ultegra Di2 6770, largely thanks to its newly available internal battery. With a normal external battery, the new group is 69 grams lighter than its predecessor.
Shimano will now offer TT/triathlon shifters at the Ultegra level as well. The ST-6871 bullhorn brake/shift levers offer the same power and performance as the Dura-Ace version.
The front derailleur has been improved with a new support bolt, intended to provide a bigger platform for the derailleur to push against as it initiates a shift to the big ring. The automatic trim function is retained.
The rear derailleur is now compatible with cassette cogs up to 32 teeth (in its GS version) and retains its crash protection features.
Both the 6870 Di2 group and the R785 hydraulic levers and brakes are scheduled to hit shops in November.