Shimano’s hydraulic disc road components were a poorly kept secret. Perhaps it was the simple inevitability of them, but by the time the official North American launch occurred, in Maui this last Saturday, they had been seen in the wild, demoed at Interbike and already launched in Europe. The need for hydraulic braking can be debated endlessly. Other than cross racers and riders in rain challenged climates are they really necessary? Is a carbon frame really necessary? Are aero rims needed by mere mortals that should really just train harder? Cycling is the endless pursuit of getting faster. There is no destination. You are never fast enough, whether we’re talking about fitness or equipment. Disc brakes are just the latest opportunity to get a little faster by going a little slower, more effectively and confidently. Necessary? Of course not. Do we want them? Hell yes.
First things first, Shimano’s Hydraulic road products are a non-series component, meaning they aren’t Ultegra and they aren’t Dura Ace, they are called R875 – another victim of Shimano’s catchy naming convention –and they aren’t compatible with any mechanical system. That’s right, they are Di2 only - for now. Despite the non-series name, Shimano tells us they are Ultegra level.
Borrowing from the Mountain Bike
R785 consists of Di2 levers, hydraulic calipers, which appear to be essentially XT mountain calipers, and 140mm Freeza rotors, more technology borrowed from mountain components, this time Saint. It is compatible with 11speed Ultegra 6870 Di2 and Dura Ace 9070 Di2, as well as 10speed Ultegra Di2 6770, the first Shimano group to use the E-Tube system. Simply tell the levers they are shifting a 10spd rear derailleur in the set-up software and you are backwards compatible. E-tube is some magical stuff.
Shimano has been in full tilt development mode for five years, which included extended tests with European cyclo-cross riders to find out exactly what riders wanted in terms of feel and power. Testing continued on the Stelvio, in the US at Mount Palomar and in Japan. In fact, it was a 2011test in Japan that Shimano Road product manger, Dave Lawrence, said was his real ‘Ah-ha’ moment. Hydraulic was the way forward, obviously in cross, but even on the road.
The XT based R785 Road Caliper
With a huge catalog of experience in mountain hydraulic Shimano knew they could make the brakes work, so it became more about creating the right feel for the road and ensuring over heating would never be an issue. Using their ICE technology, cooling fins on the pads and Freeza rotors made with steel outer plates and an aluminum inner plate that sucks heat from the steel plates, Shimano is very confident heat build up will never be an issue, regardless of riding style or descent. The Freeza rotors also have cooling fins that lower temperature at the rotor another 50degrees Celsius, according to Shimano. Pads come in the same two varieties we see on the mountain product, metallic and resin. Resin is the pad most riders will want for quieter performance and longer life, metallic is the pad of choice for cross racing or wet weather.
In all their testing Shimano has never seen a temperature above 400degrees Celsius at the rotor and with their fluid, the same proprietary mineral oil used on the MTB side, boiling at 530degrees fade should be nonexistent thanks to all this cooling. Shimano has essentially developed the brakes to reach equilibrium; they will dissipate heat as fast as it can be created. This basically means you can drag the brakes the entire way down a hill until you burn through your pads, but you will never experience fade. Shimano has done this with 140mm rotors front and back and no weight limit, while others are recommending 160mm front rotors on the road. The only reason to ride 160mm on R785 system, according to Shimano, is if you want the increased bite for nose wheelies.
140mm Freeza rear rotor with cooling fins.
Squeezing the master cylinder and reservoir into the brakehoods resulted in a much taller hood than rim braking Di2 hoods, as SRAM discovered with their RED hydro levers. Initial reports that the levers would be almost identical to current Di2 levers due to the lack of mechanical shifting internals proved to be unfounded. While at first glance not as tall as SRAM levers, they are certainly much taller than normal Di2 levers. As we discovered with SRAM, this added height is basically unnoticeable on the road. The look reminds us of the old Dura Ace 7800 hoods. The levers have a large aluminum faceplate above the blade and this seems to actually accentuate the added height, probably not intentionally. The levers are adjustable for both reach and free stroke. Free stroke adjusts the moment the pads actually contact the disc, allowing for instant or delayed contact depending on the feel you want.
In the hand however, they feel incredibly similar to current Di2, with slightly squarer edges. Shimano knows the vast majority of time is spent on the hoods, so they took these ergonomics very seriously and have done a fantastic job of replicating the great feel of Dura Ace 9070. They even extended the shift paddles so they would be easier to reach from the hoods. The only functional difference is R785 shifters have only one E-Tubeport, so no sprint shifter is available and to run satellite shifters you need the five-port junction box under the stem.
Shimanos’ R785 adds 342grams to the new Ultegra 6870 Di2group, but as that group has already dropped 126grams from the 10speed version, and most of the added weight is very low on the bike, it’s really negligible and certainly not enough to negate the systems benefits. Shimano also debuted a set of 23mm wide, 28spoke aluminum clinchers with 135mm spacing center lockhubs, the RX31. Unfortunately they are not road tubeless, which seems a shame as disc brakes are undeniably effective in the same situations road tubeless is. They also weigh an unimpressive 1795grams.
R785 On the Road
After wrapping my hands around the lever and feeling theDi2 ergonomics I have come to love I was happy. Then I flicked the brake lever and noticed a bit of play. This wasn’t play on the initial stroke, that engaged instantly, it was outward play. Push the lever forward and it moved a few millimeters. I worried this would create rattling on the road or be noticeable while shifting. Happily, like the tall hoods, it was completely unnoticeable on the road - no rattling, no slop in the action. Apparently, without cables to pull the lever tight this play is needed for the reach adjust and can be eliminated with the levers in the wide-open position.
From the rider's POV the tall hoods are irrelevant.
During 25miles of descending, from 6500feet on the volcano Haleakala to sea level at Paia, we put the brakes through their paces. While the descent isn’t the most technical, or even most high speed, we descended in a group and the accordion effect was extreme. We’d barrel into a corner at what felt like a manageable speed, then be forced to brake hard on entry, or even mid corner, as the group in front would slow more aggressively. While not the fastest way down, it presented a challenge to the brakes, which had to work almost non-stop for 60minutes. Fade was non-existent. The last pull felt as strong and progressive as the first pull. Perhaps the most incredible feat Shimano has pulled off with these brakes was the total lack of screeching. I’ve never been in a group of so many riders, using the brakes so hard, so quietly. Not in the mountains with disc brakes, not on the road with rim brakes. Amazing.
The testing grounds down Haleakala.
Like any good hydraulic disc system an enormous amount of stopping power was available to Shimano, but they knew, like SRAM before them, that rim calipers had the power to lock a wheel up. More power is not what these brakes are about. Shimano used the power to ease the force necessary to stop dramatically. They also invested that power with a smooth and intuitive ramp. It never felt grabby or created shudder in the fork blades. A single finger begins to scrub speed and that single finger, without any drama or panic, can get every ounce of necessary stopping power, even in critical situations. It reinforced our opinion of road disc in general. Its benefits will be greatest not for experienced riders that rarely brake anyway, but for new riders or nervous descenders who will gain enormous confidence from the increased control over stopping power. Shimano R785 levers combine confident braking with the‘mouse click’ ease of Di2 shifting for unquestionably the best lever experience on the road.
Our only quibble comes in part due to the hydraulic brakes incredible stopping power. In situations where massive brake power was needed previously, we would always grab the drops to get as much force as possible on the lever. With R785 all the power you ever need is accessible with one finger from the hoods. However, the wide shift paddle can actually hit your other fingers that are wrapped around the hood before you can get the pull necessary to really stop. This is exacerbated if you run a short lever pull with reach adjust and allow for a lot of free stroke.
Shimano and the Hydraulic Road Disc Future
Road disc is coming. SRAM wants it, Shimano wants it and a host of wheel manufacturers can’t wait. Shimano is already working with a consortium of other brands to lobby the UCI to allow road disc. They acknowledge it must be an all or nothing proposition for the pro peloton to embrace road disc. The massive braking differential between rim brakes and hydro disc would be catastrophic in a mixed peloton.
It’s our hunch that R785 is simply Shimano’s foot in the door of hydraulic disc braking on the road. It’s an impressive start, but clearly mountain based where the caliper is concerned and it is nowhere near as slick as the new SRAM Red hydraulic caliper, which provides a very similar braking performance. We’d bet the farm there are some very slick, road specific, hydraulic calipers branded Dura Ace we will be seeing at some point in 2014 along with some sexy Dura Ace road tubeless wheels with 135mm spacing center lock hubs. Stay tuned.
Pricing has yet to be established for the US due to fluctuating exchange rates, but in the UK riders will be paying £500, which gives us a ballpark of roughly $800. On the bright side, Shimano tells us while pricing is not final, Ultegra 6870 Di2 will cost less than 10speed 6770 Di2.
R785 Weights: Levers – 515grams, Calipers – 263grams, Hoses– 61.6grams, Oil – 21.5grams, Rotors – 205grams.
Look for an interview with Shimano’s Dave Lawrence about road disc with footage from the descent of Haleakala and another feature about new 11speed Ultegra 6870 Di2 very soon.