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Hydraulic road brakes continue to explode with the impending addition of the Shimano R785 braking system. Starting this winter, Shimano will offer this Di2-compatible road brake set, although it will not be compatible with triathlon systems. Ultegra Di2 will make a leap forward, based on the new 6800-series mechanical Ultegra group.
Shimano hydraulic disc brakes
Starting this winter, Shimano will join SRAM in making road-specific hydraulic disc brakes. The R785 series brakes system will be compatible with three different Di2 electronic drivetrains—Dura-Ace 9070, Ultegra 6770 and the soon to be released Ultegra 6870. Dura-Ace Di2 7970, the original electronic shifting system from Shimano, will not be compatible with the hydraulic braking system.
Hydraulic disc brakes offer the potential for more stopping power, modulation and superior performance in bad weather compared to rim brakes. Heat dissipation is one of the biggest technological challenges facing road-compatible disc brakes. A rider descending a long, steady climb on a road bike can accumulate enough heat to cause the hydraulic fluid driving the brake caliper to boil, which temporarily destroys braking performance. This system borrows heavily from Shimano’s well-established mountain brakes, including the Ice Technology heat management features.
“With all of our experience on the MTB side, we have pretty well documented heat management with our Ice Tech rotors and brake pads,” said Lawrence. “One of the things we’ve improved on is the rotor. The RT98 was the original Ice Tech rotor and that one was reducing the heat 100 degrees Celsius, and with the new we’re able to drop that another 50.” Shimano is not ready to reveal test data showing brake heat dissipation or stopping performance. They are still performing additional testing and working to consolidate the data before sharing their results.
As of yet, there is no hydraulic disc brake system for a triathlon bike. “Right now, we haven’t had a lot of requests for a disc brake system for tri so right now everything is road-specific,” said Lawrence.
R785 brakes are not linked to any particular component level, but Shimano road product manager Dave Lawrence described them as “Ultegra-grade.” Pricing is not yet available.
New Ultegra Di2 coming
Continuing their typical pattern of trickling technology down their component line, Shimano will release Ultegra 6870 Di2 early this winter. It will share many attributes with the Dura-Ace 9070 Di2 group that was unveiled earlier this year. “The biggest difference you’re going to find is in the weight,” said Lawrence. “You’re talking about a couple hundred grams in the system…The other thing you’re going to find when you compare is the finish on Dura-Ace is a little nicer and the tolerances is a little tighter.”
If its function truly lives up to Dura-Ace 9070 Di2 with a substantially lower price, Ultegra 6870 Di2 will be a landmark component kit—for triathletes as well as road riders. Triathlon brake/shift levers will be included for the first time with an Ultegra-level Di2 group. Enabling an athlete to shift from the brakes as well as the aerobars is one of the biggest advantages of Di2 component groups.
This system will be based on the E-Tube platform, allowing shift patterns to be custom programed based on individual preferences. Athletes using this system on road bikes will be able to easily install aerobar extensions shifters for occasional triathlon use without sacrificing drop bar function.
Gearing options will also expand to include a 32-tooth rear cog for an easy uphill gear and chainring combinations including 52-36 and 46-46 in addition to the standard 53-39 and 50-34 configurations.
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