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Shimano’s hydraulic disc brakes for 11-speed mechanical groupsets is a mightily impressive bit of kit

There has been much anticipation surrounding Shimano’s latest ST-RS685 hydraulic disc brake levers with mechanical shifters ever since they announced them earlier this year. We’ve had to wait ages to get our hands on a set, so when the new Cannondale Synapse Disc rolled into the office recently sporting the new brakes, we rubbed our hands together in delight. 

The reason this groupset has been so eagerly anticipated (and in much demand) is because it makes disc brakes a more affordable reality, both for manufacturers speccing new bikes and customers building their own bikes. Previously you’d had to buy a Shimano Di2 groupset to take advantage of their new hydraulic disc brakes, but now Shimano are offering a hydraulic brake lever with mechanical shifters, we’re going to start seeing Shimano disc-equipped bikes coming in at much lower prices. This Synapse by way of an example, costs £2,500, massively cheaper than the Di2 disc-equipped bikes we've tested so far this year.

The new RS685 STI levers operate the new BR-RS785 brake calliper, essentially it’s the same as the first generation R785, but the brake hose uses a direct hose connection which goes straight to the top of the caliper. The disc rotors on this bike are Shimano recommended 140mm front and rear IceTech rotors, with the distinctive finned design and a three-layer sandwich structure of stainless steel and aluminium helping to dissipate heat.

The brake lever and calliper are non-series, it’s designed to be run with any of Shimano’s 11-speed mechanical groupsets, so that’s Dura-Ace, Ultegra and now, 105. That immediately opens up a raft of build options, the levers and calipers cost £479.99 and 105 is £600, but you can get it much cheaper than that if you shop around. 

I've' spent the past couple of weeks riding the new brakes, and I have to admit, I’m really taken with them. I’m already a fan of disc brakes, but I’m certainly not pushing for their adoption, I just recognise that they offer superior braking performance with far improved lever feel, and that really appeals to me. I also don’t mind the look of disc brakes on road bikes, but that may be because I’ve been riding mountain bikes since before disc brakes were common and I’m sort of used to their aesthetic. I also feel that the disc Synapse is a cleaner looking bike than the rim brake model we tested last year. You might not agree of course, and that’s just fine.

Looks aside, the most important thing is the performance, and in that respect the brakes and shifters are faultless. To glance at, the lever looks like any regular Shimano mechanical lever, and when you first clasp your hand around the hood it feels almost identical. Look a bit closer and you can see that Shimano have lengthened the STI, but kept the width and height about the same. It's a minute change, but enough that is has allowed them to squeeze an oil reservoir inside, along with the mechanical shift components. It must be cosy in there. It’s a typically smart bit of design from the Japanese company.

Riding the bike and flicking the shift levers feels just like any other bike equipped with a Shimano mechanical groupset. Pull the brake lever though, and it’s a world of difference. The brakes are powerful, strong and, really they just feel fantastic. The amount of lever travel is just right, they’re easy to operate from the hoods, from the drops you can use one finger all of the time, even when you’re panic braking because a car has pulled out in front of you.

I’ve been riding the brakes in loads of weather, purposefully heading out in the rain (it's a tough job sometimes) and on roads covered in crap (which most of the Cotswolds lanes appear to be at this time of year) and up and down the steepest hills. The nice thing is that the lever feels the same, all the time. In any weather. You can splash through puddles and ride through mud, caking the rim, but the disc brakes will give you the same predictable braking performance.

I’ve been in situations on steep descents on rim brakes when I’ve had scary “will I be able to stop” moments. That's not the case with these brakes. That provides a huge amount of confidence that the brakes will deliver when you really need them to. There's also none of that scraping and scrunching side from a rim brake, as the brake blocks first try and clear mud and water from the rim before finding enough purchase to slow you down.

There’s not been one occasion when I wished to be back on a traditional bike. Even lugging their slight weight penalty up hills. They just work, all of the time. No ifs or buts, just brilliant performance.

I’ve had a lot of people asking me if the brakes are too powerful and if I’ve been constantly locking wheels. No is the simple answer. You can easily lock the wheels if you grab a load of brake lever very suddenly, but that is the same of any well setup braking system, rim callipers included.

It’s a bit like when you get in hire car, and the first time you go for the brakes the bite point and lever travel is completely different to the car you’re used to, usually resulting in a bit of a comical jerk at the exit of the car hire car park. Once you’ve made that first mistake, you don’t tend to make it again. Riding hydraulic disc brakes is a bit like that, in that it takes a little while to get used to riding them, but once you do, it’s very hard to go back to a bike without disc brakes.

With this new groupset, widespread disc brake adoption just took a serious leap forwards - disc brakes are here to stay. Yes it’s still expensive technology at the moment, but this groupset is a definite step in the right direction and makes them that bit more affordable.

A pair of RS685 shifters and calipers cost £479.99 and should be available from Shimano distributor Madison now.

 

David has worked on the road.cc tech team since July 2012. Previously he was editor of Bikemagic.com and before that staff writer at RCUK. He's a seasoned cyclist of all disciplines, from road to mountain biking, touring to cyclo-cross, he only wishes he had time to ride them all. He's mildly competitive, though he'll never admit it, and is a frequent road racer but is too lazy to do really well. He currently resides in the Cotswolds.

28 comments

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Super Domestique [1619 posts] 3 years ago
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I haven't been a fan of the lol of disc brakes on road bikes. I've said it a fair few times on here tbh.

But that looks really good.

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Peowpeowpeowlasers [546 posts] 3 years ago
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Do they make a racket in the rain, when not braking?

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CXR94Di2 [1858 posts] 3 years ago
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Mine from time to time pick up a little debris when it's raining , especially at the moment with so much mud on the roads from farmers traffic. I would hardly call it a racket, more a jingle.

What disc brakes do is inspire confidence that they will work first time when it's wet/raining. Rims brakes will never to able to offer guaranteed braking in the wet first time.

Also disc brakes offer better modulation

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will harrison [15 posts] 3 years ago
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I've been running 11spd shifter with mechanical (bb7's) discs for 4 years.....admittedly the Alfine hub is quite weighty  1

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giobox [361 posts] 3 years ago
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Wheels are still the weak link, and probably will be till the UCI legalise them for competition and they can become the mainstream option. Until then, the range of options will continue to be much more limited in comparison to rim brake wheels.

This is true even at the very high end (Zipp 202 disc I'm looking at you..) you still get a rim with a redundant and heavy brake track.

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Stefan M [21 posts] 3 years ago
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For wheels have a look at the new 2015 DT Swiss RC 28 and RC 38 Spline DB. They come in both clincher and tubs and the new clinchers are also tubeless compatible! The RC 28 Spline C DB weigh in at 1325g and the RC 38 Spline C DB at 1455g.

I'm ordering a set of the RC28 C DB to run tubeless. Can't wait!

I have found out that the RC28 is only available as a QR option for the first part of 2015 but will have the full range of axle options later in 2015 so double-check before ordering if you need a specific axle config.

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joules1975 [485 posts] 3 years ago
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You are right about dedicated 'road' wheels, but I've been looking around and if you broaden your mind a little, it's surprising how many 29er mountain bike wheels are out there that will work pretty well with road tyres on. Not many deep section options admittedly, unless you gave deep enough pockets for envie rims or similar.

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IanEdward [126 posts] 3 years ago
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Can anyone find those rotors aftermarket?

Madison seem to offer the XTR 4-arm 140mm rotors although I'm sure these are actually out of stock.

The only other offering is the Saint 140mm Freeza rotor which seems overkill for a road bike! Also centre-lock only, any options for 6-bolt?

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DrJDog [432 posts] 3 years ago
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How easy is it to slot a back wheel in and out? I sometimes have a grand time with my rim brake rear wheel (unless I deflate the tyre), I imagine having to get a disc into a teeny tiny slot makes it much harder...

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hsiaolc [367 posts] 3 years ago
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Peowpeowpeowlasers wrote:

Do they make a racket in the rain, when not braking?

No, and if there is any noise it is negligible.

I love mine with DI2. It is the best thing for road bikes. I used to fear sudden breaking and in the rain I always have had a hart time stopping.
Now with my disc brake I love every ride. I love every braking chance. It is so powerful and easy. No longer I have to squeeze the brake lever so hard.

With a bit of squeeze you stop very smoothly with amazing modulation.

Its time everyone gets on disc brakes. I am not sure why it took so long and even now I am the only one in the whole building (100 bikes or so) and I am the only handful who uses them.

definitely a vast improvement on safety for the bike for commuting.

I love mine and I super recommends them to everyone.

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hsiaolc [367 posts] 3 years ago
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DrJDog wrote:

How easy is it to slot a back wheel in and out? I sometimes have a grand time with my rim brake rear wheel (unless I deflate the tyre), I imagine having to get a disc into a teeny tiny slot makes it much harder...

On the contrary it is extremely easy to slot the wheels back in. No need to play around with cables or levels on the brake cables to loosen it. No ever need to worry about re alignment of the brake pads to the wheel. You only need to slot it in and its done.

And you definitely don't need to deflate the tires to fit your wheels back.

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Super Domestique [1619 posts] 3 years ago
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@ hsiaolc.
what bike do you have with the hydro and di2 set up?

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Super Domestique [1619 posts] 3 years ago
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@ hsiaolc.
what bike do you have with the hydro and di2 set up?

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joemmo [1164 posts] 3 years ago
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joules1975 wrote:

You are right about dedicated 'road' wheels, but I've been looking around and if you broaden your mind a little, it's surprising how many 29er mountain bike wheels are out there that will work pretty well with road tyres on. Not many deep section options admittedly, unless you gave deep enough pockets for envie rims or similar.

Joules - could you share the info on the 29er wheels you found that would work because my research showed the opposite. Most were either too wide at the bead or not rated to support road tyre pressures. cheers

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TDP [2 posts] 3 years ago
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I'd like to know where you would put the levers in the 105-ultegra-dura ace range?

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wstephenson [15 posts] 3 years ago
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Do the brake levers clatter on the body of the STI when riding over rough stuff? That was the most mentioned problem with last year's model.

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wstephenson [15 posts] 3 years ago
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Do the brake levers clatter on the body of the STI when riding over rough stuff? That was the most mentioned problem with last year's model.

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usedtobefaster [207 posts] 3 years ago
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Can someone comment on how these brakes are serviced - I'm thinking changing the hydraulic fluid?

With Shimano MTB brakes you simply remove the reservoir cap on the lever, loosen the bleed nut on the caliper and pump the lever whilst pouring the new fluid into the reservoir. With these road levers the reservoir looks inaccessible.

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ronin [279 posts] 3 years ago
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Disc brakes...I only ever think about 'em when I'm heading downhill in the rain far too fast  1

It will be nice when things stabilize and they are not new tech on road bikes anymore...not sure I can wait 5 years though.

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hsiaolc [367 posts] 3 years ago
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wstephenson wrote:

Do the brake levers clatter on the body of the STI when riding over rough stuff? That was the most mentioned problem with last year's model.

On mine it doesn't but I have the DI2.

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hsiaolc [367 posts] 3 years ago
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Super Domestique wrote:

@ hsiaolc.
what bike do you have with the hydro and di2 set up?

I have the Rose Xeon DC 3100 Di2 with a lot of upgrades options chosen.

I absolutely love this bike. Love the brake!! I bought it for that purpose and in return I got much more than I expected.

I figured my life is worth more than the cost of the bike so I went for it. Not regretting it all.

DI2 is amazing too.

I retired my Canyon Ultimate AL.

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Super Domestique [1619 posts] 3 years ago
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Thanks

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HandyAndy247 [12 posts] 3 years ago
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I so want to try a set of these. If they have any stopping power close to MTB brakes I'm sold.

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Kim Chee [39 posts] 3 years ago
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My 5800 and 6800 brakes are so fabulous these are irrelevant to me; BUT if I were buying a touring frame disc tabs would be a must. No disc envy folks-if your current set up does the job you need it to do just be happy to ride.

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Nick T [1099 posts] 3 years ago
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DrJDog wrote:

How easy is it to slot a back wheel in and out? I sometimes have a grand time with my rim brake rear wheel (unless I deflate the tyre), I imagine having to get a disc into a teeny tiny slot makes it much harder...

You do know that brake calipers have a release mechanism to let you get the tyre past the pads, right?

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JumboJuice [35 posts] 3 years ago
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No, there's rubber insert so the levers don't clatter or rattle, on my Trek Domane Disc 4.5.

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Angeld [16 posts] 3 years ago
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I'd love to see a head to head review of these up against the SRAM Force 22 discs.
Might help to get a little market perspective.  39

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David Arthur @d... [824 posts] 3 years ago
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We've got the new SRAM hydro disc groupsets on test at the moment and we'll be reviewing them soon Angeld