- Shimano R785 shifters are part of the first hydraulic road disc offering from the Japanese component giant.
- The size and shape of the shifter is almost identical to shifters with cable-driven brakes.
- Hydraulic lines.
- Shimano's Ice-Tech caliper and rotor is capable of shedding heat quickly enough that the fluid in the hydaulic line doesn't boil, ensuring reliable brake performance.
- Hydraulic disc brake calipers.
- Ice-Tech rotor.
- R785 shifters, compatible with Shimano's E-Tube Di2 groupsets.
- The shape of the shifter is remarkably similar to standard versions.
- Shimano's centerlock disc-compatible road hubs.
- 3T Accelero 40 Pro disc-compatible wheels.
- 3T's wheels are intended for cyclocross primarily, and they are built on a 40mm-deep aluminum rim.
- Even ultra-posh German wheel maker Lightweight is experimenting with a disc-compatible wheelset.
- Specialized Roval Rapide CLX 60 aero wheel with disc hub.
- DT Swiss RC38 aero wheel with disc hub.
Wheels, frames and components all ready for road hydraulic disc brakes.
Two years ago there was speculation. Then a few models from smaller manufacturers showed up at Eurobike 2012, but the component giants were still coy about hydraulic road disc brakes. SRAM debuted their version earlier this year and now, finally, the whole of the industry has caught on and caught up. Hydraulic road disc brakes are ready to take off.
The value of hydraulic disc brakes for road bikes has been covered on this site and others, but the justification for their use on road bikes is pretty simple: They work much better than rim brakes. Hydraulic disc brakes can produce more stopping force than rim brakes and require less hand force to do so. And hydraulic discs allow for much greater control of that power. Rim brakes are sufficiently strong to lock up a wheel and skid across a road, but hydraulic disc brakes make converting that power into stopping performance easier. Practically every high-end mountain bike has hydraulically driven discs because when you’re barreling toward a tree or a rock or a cliff, brakes have to work ideally, and stopping performance is no less important on the road.
Cyclocross, a hybrid between mountain biking and road riding, paved the way for road disc brakes, so some wheel manufacturers were already equipped for disc brakes on road bikes this year, and now many of them have built wheels around discs. Seven of the 10 most popular wheel manufacturers at Ironman Hawaii in 2012—Zipp, Hed, Easton, Bontrager, Xentis, Shimano and Enve—now have disc-compatible road wheels. Other important aero wheel makers such as Rolf Prima, DT Swiss, Specialized, 3T and even Lightweight are also now making deep-dish wheels with disc brakes. There are even more options with shallow rims.
Wheel options are exploding for 2014, but they weren’t the hold up for this model year. Frames and components were the limiters, and now there is an abundance of choices. Practically every large road bike maker has a disc-compatible model on display here at Eurobike. And the choices aren’t limited to Roubaix-style bikes designed for comfort. Fully dedicated race bikes designed such as the Cannondale EVO can now be had with disc mounts. Triathlon bikes are the noteworthy exception. We haven’t yet covered the full expanse of Eurobike, but it seems popular tri bike manufacturers aren’t yet making disc-compatible aero bikes. A test conducted by Culprit Cycles, a small brand that does have a disc-specific tri bike, found that a disc brake did create slightly more aerodynamic drag than a cable-driven version. Tri bike makers may have decided to overlook the option for the sake of straight-line speed, or maybe the technology will just be a year behind road bikes. But for now and next year, very few tri bikes offer the option of disc brakes.
In addition to road bike manufacturers creating the platform for disc brakes, Shimano’s entry was the final piece to industry-wide adoption. They have joined the move to road discs with the R785 Di2 shifter, compatible with both Ultegra 6870 and Dura-Ace 9070 Di2 component groups. Shimano doesn’t yet have a hydraulic system that is compatible with cable-actuated drivetrains. While the R785 system is still a very high-end product, Shimano’s involvement with road discs carries a lot of weight. Not only are they a massive supplier of parts for road bikes, but SRAM and Shimano are now poised to compete to get cyclists to buy their hydraulic road disc brake systems. Both of these innovative companies fighting for the same customer means the technology is likely to improve and expand rapidly. Maybe more affordable options will be on display at next year’s event. Until then, all the pieces are now available for hydraulic discs to be a logistically viable alternative to cable-driven stoppers, even though the price is still high.