Ultegra 6870 Series group

After months of speculation, leaks, but little actual info, Shimano’s highly anticipated hydraulic road disc brake system is finally here. Oh, and there is a new 11 speed Ultegra Di2 group as well. At this point in the game, Shimano trickling down the new features from Dura Ace 9070 is just about a given, but there are some great updates to an already amazing system. I’ve been on an Ultegra 6770 Di2 equipped bike for the past few months, and riding is believing. With 6870 only promising to be better, the future is looking bright for Shimano electronics – and road discs.

Want more on Shimano’s first hydraulic road disc/Di2 system? Find it all with exclusive tech and insight directly from Shimano after the break!

Shimano R785 Hydraulic disc brake Di2 road

Shimano’s ST-R785 shifter and BR-R785 hydraulic disc brakes

Now for the reason you’re all here – Shimano’s R785 hydraulic system. While you may have been expecting to see a specific Ultegra branded system, the Ultegra-level system allows it to exist on its own, since it’s not a complete drivetrain. The beauty of the ST-R785 shifters and BR-R785 hydraulic disc brakes is that thanks to the E-Tube wiring system, the R785 group can be added to any E-tube equipped Di2 group. That means Dura Ace 9070, new 11 speed Ultegra 6870, and 10 speed Ultegra 6770. We asked Shimano Road Product Manager Dave Lawrence about the cross compatibility, and he said since the rear derailleur essentially tells the shifter what to do, the ST-R785s are basically plug and play for any E-Tube system. He did mention that older 6770 systems that have not been updated recently may need a firmware update, but other than that they will all work together.

Shimano Ultegra Di2 vs r785 Shifters

ST-R785 Shifter on the left, Shimano Ultegra 6870 Shifter on the right.

The same goes for upgrading a 6770 10 speed Di2 group to 11 speed – the drivetrain would need to be replaced, but you could keep the 6770 shifters as they will be compatible with the 6870 parts. Of course if you go that route you will miss out on the addition of a 3rd port on the shifter for use with the SW-R610 sprinter shifters. Shimano has also continued to improve the ergonomics on the 6870 shifter with easier access to the shifter buttons, and increased contrast in texture between the two buttons. Like Dura Ace 9070, the 6870 shifter can be customized with variable multi-shift speed and shift count when you hold down the button in addition to firmware updates rolling out in the future.

Side by side, perhaps one of the best features of the ST-r785 is how similar it is to a standard Di2 lever in size and shape. Thanks to the  relatively tiny internals for an electronic vs. mechanical shifter, there is plenty of room for the hydraulic master cylinder. The result is a shifter without any additional girth in order to squeeze in the hydraulics. Built into the ST-R785 lever are also reach and free stroke adjustments allowing riders to dial in the perfect position and obtain more braking power from the hood.

BR-R785_with_RT99-S

One of the big questions on everyone’s mind when it comes to Shimano’s road discs will likely be – what about the heat? According to Shimano, for them – it’s a non issue. Boldly showing their confidence in their technology, Shimano is recommending 140mm rotors front and rear for the road, regardless of weight – as long as you are using the SM-RT99 IceTech Rotors and Ice Tech finned pads. The rotors are identical to the rotors recently launched with the new XTR brakes, that were initially developed for Saint brakes. These rotors use the IceTech aluminum core clad in stainless steel, but take it a step further with the aluminum core flowing out into the center of the rotor in the form of “Freeza”cooling fins that help to further radiate heat. Shimano points out that the finned brake pads can reduce heat build up by 50° with another incredible 150° of cooling offered from the RT99 rotor compared to a standard steel rotor. While 140mm rotors are recommended front and rear, SM-RT99s will be offered in 140, and 160mm.

When asked what allowed Shimano to be so confident in the heat management of such small rotors, Lawrence stated it’s due to all of the research and development of the IceTech system from the mountain bike side of the business. “Our knowledge of heat management from mountain bikes is what allowed us to create this system,” said Lawrence. In fact, when asked if the  BR-R785 was developed specifically for road bikes, we were told it was essentially a re-purposed mountain bike brake caliper that has been tuned for road use. That means the aluminum caliper uses the same brake pads as most of the current two piston Shimano mountain bike brakes offering consumers easily available replacement pads.

The other great news for the system is that it uses all of the same hose fittings as current hydraulic systems and is bled with the same method as well. Hoses will attach to the levers with the standard Shimano olive and barb with a threaded barrel, and the bleed system uses the Shimano bleed funnel at the lever with a syringe at the caliper. According to Lawrence, “The First prototypes actually had a different bleed process. But going into the road side of things, we knew some shops are road specific so they may not have as much experience with disc brakes. Realizing that meant having a consistent bleed process across the board was important.”

Shimano Rt99 Rotors Road Disc

IceTech SM-RT99 Centerlock Rotors

Since Shimano requires the use of the SM-RT99 rotors to guarantee proper heat management, that also means users will be forced into Centerlock rotors as the RT99 is not offered in 6 bolt. In order to provide something to roll on, launching along with the BR785s will be a set of 11 speed compatible Centerlock hubs and wheelset. The HB-CX75 hubs will be offered in 28 hole drilling, are 11 speed compatible, and can accommodate a 140mm rotor.

The Wh-RX31 Centerlock disc wheelset is specified for road and cyclocross use and are standard clinchers with a slightly wider 17mm internal width for better suiting wider tires. Both the hubs and wheels will be available in 135mm rear hubs only. We asked if more wheels and hubs were in the pipeline and Dave said there would be higher end options introduced in the near future along with companies other than Shimano working on compatible wheels and hubs.

Shimano Ultegra Di2 11 speed Derailleurs

Almost overshadowed by the hydraulic discs, the new 11 speed Ultegra Di2 includes the expected extra gear, but also drops a total of 126g and adds some new features as well. One of the most welcome is a redesigned rear derailleur that has a wider link for better shifting and is offered in a mid-cage GS version which will allow up to a 32t rear cog – a first for Di2. Combined with the new Ultegra 4 arm crank that was unveiled with the 11 speed mechanical group, the 6870 group offers a wide range of gearing so almost all riders can find the perfect set up. Cranksets can be configured in 53-39, 52-36, 50-34, and now 46-36 for cyclocross.

6870’s E-Tube wiring system is also updated to offer a cleaner install while making the addition of satellite shifters and special programming easier.

Shimano Sprint Shifter SW-R610 SW-R671-R_L

As mentioned, the new ST-6870 shifter now has three ports that will accommodate the additional Sprinter shifter and satellite shifter. The SW-R610 Sprinter shifter is not compatible with 10 speed Ultegra levers. The other big news for Ultegra 6870 is the introduction of the ST-6871 or Ultegra specific TT shift/brake levers. The brake lever shifters aren’t pictured, but the system offers the same multi-position shifting  and braking while maintaining E-tube functionality.

Weights:

In order to drop the 126g over 6770 Di2, you will need to use the internal battery for the system, for a combined total weight of 2359g. Otherwise, with the external battery the 6870 Di2 system is only 69g lighter but hey, lighter weight  and another gear is good, right? 6870 is also 9g lighter than 6800 mechanical with the internal battery. Weights are with an 11-23 cassette, 114 link chain, and a 170mm 53-39 crankset.

As for the R785 system, the complete system including shifters, brakes, hoses, mineral oil, and two RT-99 rotors works out to be 1066g. Compared to 6870 shifters with rim brakes, the hydraulic system adds less than a pound – somewhere around 340g.

R785 Weights:

  • ST-­R785 – 515g
  • BR-R785 – 263g
  • Brake Hose (BH59) – 61.5g
  • Mineral Oil – 21.5g
  • Rotor – RT-99 (140mm) – 205g

Availability:

Availability for all all parts is expected in November with Shimano holding off on setting pricing due to possible fluctuations in the exchange rate between now and then. Until then, Shimano’s sponsored athletes will continue testing, but you can probably expect to see the new R785 system on a cyclocross course near you, this fall.

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85 Comments
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toni
toni
9 years ago

way better look than Sram levers…..

Aaron
Aaron
9 years ago

No 6-bolt Rotors? Ughhhhh. Classic Shimano…

Sean R
Sean R
9 years ago

Aaron- Centerlock is part of getting the heat removed from the system away from the hub bearing, Icetech 160mm rotors will still be available in 6 bolt.

xcgeek
9 years ago

yeeeeees. super bummer it wont be available until november… or very hard to get in november. come on shimano, you cant do this months into cyclocross season! so may disc cx frames! so many!!

yesPlease
yesPlease
9 years ago

NOVEMBER!!!! Missed the boat for cross season….

CXisfun
CXisfun
9 years ago

DAMMIT! I’ll still get it, though I won’t be happy being forced to wait until the tail-end of CX season…..

Brandon
Brandon
9 years ago

Finally! Can’t wait…..

PDXFixed
9 years ago

SRAM is getting left in the dust

Jordan
Jordan
9 years ago

Sean R

Centerlock removes more heat from a rotor than 6-bolt. I dont remember exact numbers, but centerlock removes more heat.

Gilhooley
Gilhooley
9 years ago

What about hidraulic brakes for mechanical groups ?
Coming later or is it Di2 or bust ?
None of you “journalists” from Bikerumor thought to ask that question, eh ?

PDXFixed
9 years ago

Would it be safe to say that upping the rotor size would help with heat management, making a 6-bolt setup possible?

xcgeek
9 years ago

well, bikerumor said these particular rotors will be available in 160… so they are meant to work with 160 rtr’s. who says they are any different dimensionally than an slx, xt or 6bolt? only time will tell but i say 160mm 6bolt for the masses!

Tim A
Tim A
9 years ago

@Gilhooley,

Way to sound like a d**k. I’m sure that they’ll jump on your request, seeing as you asked nicely and all.

Lucca
Lucca
9 years ago

SRAM has come a long way in only 25 years..

Wojtek G
Wojtek G
9 years ago

@Gilhooley – impossible to fit both mechanical shifting internals and hydraulic internals in one shifter body… unless you want it to look like SRAM’s gizmos, I mean.

As much as I love road stuff from SRAM, this time Shimano clearly wins. I won’t use these parts personally as I believe in cantis for cross and calipers for road, but these really are sweet!

Rain
Rain
9 years ago

Does it tell the NSA what gear I’m in?

SAIG
SAIG
9 years ago

Much better looking than SRAM shifters. Would they work with the SRAM hydro rim brake? My personal preference is calipers for road.

Fred
Fred
9 years ago

The weight penalty is nearly a pound. That seems significant doesn’t it? I’m all for disc brakes, but I’d hate to add any more weight.

Victor
Victor
9 years ago

Would the 32T rear cog work with the Dura Ace RD-9070 rear derailleurs or only with the new mid-cage RD-6870 ultegra rear derailleur.

Gummi
Gummi
9 years ago

Victor, by the sound of it a 32T would only officially work with the Ultegra medium cage. However, I have seen a few short cage 7970 rear mechs coping with 30T and possibly 32T. There is also the possibility of retrofitting a 6870 medium cage to a 9070 mech.

maddogeco
maddogeco
9 years ago

Shut up and take my money!

pornitswhatlwouldratherbmaking
pornitswhatlwouldratherbmaking
9 years ago

That has to be one of the uglest rear mechs out there. That linage arm on the bottom, come on. And while im at it, bitching, how unsleek can you make a disc caliper. l love m785s on a mtb but couldnt they make it look more aero looking. Dont get me wrong im 100% on the road disc brake band wagon but rebadging xts is kinda lame. i bet Dura Aces will look much better.

Jacob
Jacob
9 years ago

Adding weight is something that people have to decide if the benefit outweighs the penalty of just less than a pound. It happened in mountain biking, first with front suspension, then disc brakes and then full suspension. With pro teams having to add weight to their bikes to meet the UCI minimum weight I don’t think adding less than a pound of weight will be a problem. With the very average braking performance of rim brakes on carbon wheels I will gladly make the switch to disc brakes but looking at ZIPP, you will be adding another pound if you use their 303 disc wheels. That’s 2 pounds you will now be adding to your bike and as far as I understand, disc brakes are not very aero. Whats the point of releasing helmets that might save you 3 seconds over some random distance, bike frames that will save you ‘x’ amount of seconds over the same random distance if you are just going to spoil it with non aero disc brakes. It does seem a bit like the road bike industry is trying to develop 2 different tends that are in conflict with each other.

William T
William T
9 years ago

SWEETNESS!!!

Ive been waiting to buy a new bike until I could get electronic shifting and hydraulic breaking in the same package!!!!

My only complaint is why such a tease? Why not launch the end of summer… Be loaded on all soon to be launched 2014 bikes! And most importantly hit cross season!

Brian
Brian
9 years ago

This is a lot of technical development just for carbon clinchers.

Pancakes
Pancakes
9 years ago

How will they differentiate Dura Ace Di2 from Ultegra Di2 now?

MMyers
MMyers
9 years ago

@Pancakes

>$$$$$
<Weight

Jonny
Jonny
9 years ago

It’s a shame electronic shifting is stupid… I like the hydro discs though.

MMyers
MMyers
9 years ago

Stupidly works better than anything else, I suppose.

maddogeco
maddogeco
9 years ago

@Jacob disc could be a aero advantage. like the winglets on a plane wing it stops the turbulence coming back into the back half of the inside of the rim. (the rim new the BB on the front wheel if that makes sense) Orbea has been testing disc in a wind tunnel, “with good results” so it may not be that bad. and it will improve over a year or 2.

Brandon
Brandon
9 years ago

@SAIG: they don’t use the same fluid, I highly doubt SRAM’s hydro rim brakes will work with these levers.

xcgeek
9 years ago

@Zach Overholt if Shimano is confident with heat control in a 140mm rotor with fins (SM-RT99) that is only available as a centerlock, I would hope a 160 6-bolt icetech will produce comparable heat control due to more surface area… which will ultimately break the masses free from using centerlock hubs with this new awesome system. what do you think? …maybe there are some “max rotor size” restrictions on cx forks and frames…

Leo
Leo
9 years ago

It should just read….you want them but you can’t have them. Next they will roll out their new Snowbike gruppo with availability in March. Better stuff than Sram but lame execution.

Psi Squared
Psi Squared
9 years ago

@Jacob: there’s more to aero drag than just the drag of disc brakes. The drag of disc brakes doesn’t change anything to do with the drag of a helmet. Moreover, advancing technology doesn’t march along one set path with one overriding parameter like aerodynamics. The issue with braking is greatly improved modulation and consistency, along with greatly reduced thermal load for rims, particularly composite rims. Aero benefits are not at the top of the braking priority list for the vast majority of riding conditions and thus don’t have to come first in brake development.

bin judgin
bin judgin
9 years ago

[deleted]. this stuff will rule. sram should do electric now to not get left behind. but lets face it: sram pushed hydro road to market and shimano had to react. leaders & followers.

Ashok Captain
Ashok Captain
9 years ago

Hmmm . . . . “Freeza”cooling fins that help to further radiate heat. Shimano points out that the finned brake pads can reduce heat build up by 50° with another incredible 150° of cooling offered from the RT99 rotor compared to a standard steel rotor.”

Yay! But methinks they aren’t aerodynamic/ cause turbulence. Maybe okay for cross . . . .

The crankset looks very ‘stealthy’ and ugly-pretty.

+1 – Jacob and totally agree with pornitswhatlwouldratherbmaking “rear mechs. . . linage arm on the bottom, come on. And while im at it, bitching, how unsleek can you make a disc caliper.”

A cynical cyclist

JN
JN
9 years ago

I too would love to pair these with some hydro rim calipers! SRAM red would be great, although the different fluid probably means different and incompatible seal design. How about the Magura TT ones cervelo and garmin have been rocking? May even save weight over standard ultegra cable brakes.

Mindless
Mindless
9 years ago

RT85 160mm 6bolt ice-tech rotors is what I would use.

Use XTR Trail and XT on my mountain bike – awesome brakes. Unlike SRAM.

the_contrarian
9 years ago

Hey guys…I’d be waiting for the reviews (you know, the ones where the product is actually ridden not just re-written…) before deciding on what size rotor to run given that ‘over-braking’ tends to have a higher degree of consequence on a road bike than a mountain bike ;). Also I’d say that if you don’t like the look or ‘blocky’ style, not to worry, just but the levers and a set of XTR callipers!
As a bonus the new mid-cage RD should make mountain hacks a bit easier.

What I don’t understand is why there would have to be bleeding and parts compatibility to assist road-only shops – if the mechanics don’t have the experience, they are going to have to learn to do it anyway – don’t get me wrong, as a home mechanic I’ll be glad that my spares and tools will be suitable for the new standard, all I’m saying is it just seems a strange explanation…

@William T; don’t worry about the release date – I’m sure you’ll see it on plenty of 2014 OEM bikes before then (my personal hope is for the whole group to appear on one of Giant’s Allux TCX’s
at a reasonable price. Giant are usually the value leaders here in Australia…)

NASH
NASH
9 years ago

How will I attach these to my current bike? Do Shimano supply cable-ties or self taping screws?

Wojtek G
Wojtek G
9 years ago

@SAIG – impossible. Shimano hydros work on mineral oil while SRAMs work on DOT fluid.

Pete
Pete
9 years ago

Good luck getting a decent bleed in 95% of the shops in the country. These things are super cool but if you don’t know how to bleed brakes properly, you better learn before you buy. After one trip to your LBS you WILL be servicing your own brakes. Unless they have some MTBers on staff of course…

cyclestar
cyclestar
9 years ago

Is it possible to use DI2 on 3×11 Drivetrains, as I really prefer triple chainrings in front.

Does anybody know a disc only roadfork with 1 1/8″ straight steerer and full carbon and mounting height of 370mm (like most normal roadbikeforks), which is affordable (<300€) and weight less than 470 Gramm and has postmount discbrake tabs. Thank you for any idea.

dl
dl
9 years ago

@jn I had the exact same thought about the Magura brakes. I think I’ll need to steal a buddy’s P5 and see whether I can rig it to my XTR brakes; if that works I may have to ride a shimano road group for a change.

Ck
Ck
9 years ago

Centerlock hub requirement really hurts this. Without data backing it up i’m calling BS on the heat management benefit.

Nathan
Nathan
9 years ago

I always thought Shimano were onto something with their heat dissipation priorities in the disc brake arena. Makes absolutely perfect sense for road bikes.

Very tempted to shell out for those RT99s on the MTB!

Jeb
Jeb
9 years ago

Everybody I’ve ever met who thinks they can’t live without Disc brakes on the road has either been a MTB’er (who don’t know crap about road riding) fat or slow or a combination of the three. The fast road guys I know when asked the question always respond with “my current brakes work fine?”

heatwave23
heatwave23
9 years ago

Hey bike industry PLEASE stop solving problems that do not exit to sell more product

11 Speed = no real performance gain and the likely hood of having to buy new wheels
Electronic = Marginal gains, More technical issues that cannot be fixed on the road
Hydraulic brakes = Marginal gains, more weight and having to buy new frame + groupset + wheels
Semi Aero road bikes = Less than Marginal gains even for what is considered a fast cyclist
Aero helmets = butt ugly and they have to be hotter
10 million BB standards = confusion

satisFACTORYrider
satisFACTORYrider
9 years ago

@jeb-what’s to know about road riding when it comes to brakes? nothing. fast guys aren’t about brakes on the road or mtn. you can be a heavier/bigger clydesdale rider who can benefit from a road disc brake. applying any brake is a skill.