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We've had a go on the new Hydraulic Di2 system from Shimano. What's it like? Read on...

So we're here in Sicily trying out Shimano's hydraulic road disc brakes for the first time. They've been a long time coming, but they've landed. And first impressions are good.

Discs are only a part of the wider redevelopment of the Ultegra groupset, which has moved to 11-speed and is available with either mechanical or electronic Di2 shifting. We've covered the launch of this equipment in detail before on road.cc, so we won't go it in great detail now. Suffice to say that the mechanical incarnation of the the groupset borrows heavily from Dura Ace, and the electronic shifting is realised through derailleurs that are, to all intents and purposes, the same. Okay Dura Ace is a bit lighter, but in terms of form and function there's very little between them.

In contrast to SRAM's tall levers that accommodate the master hydraulic cylinder and the mechanical workings, Shimano's discs use Di2 levers that are, to all intents and purposes,  empty thanks to the switch to switches. That means that Shimano are able to run hydraulic discs from a lever that's the same size as the non-disc Ultegra unit. The brake levers pivot differently, leaving the shiny master cylinder static up top.

One thing that we've been hearing on a more or less constant basis is that the switch to discs is market driven, and not something that's particularly interesting the pro cyclists. That being the case it was certainly interesting to hear Andy Schleck, who's been present at the launch, talk about the limitations of braking on a current professional bike, with carbon rims and callipers. He for one seems to be in favour of a switch to discs.

From Andy's point of view the possible switch to discs isn't so much a boon in terms of overall braking power as consistency in poor conditions. "If you're descending in the wet then there's often water on the braking surface of the rim", he told us. "You need to brake in time to clear that water, you're often dragging the brakes into a corner with no guarantee of what's going to happen". Similarly on a hot alpine descent Andy tells us that the difference in braking feel and power is very different from the top to the bottom, as the brakes heat up the rim surface.

So is disc braking the beautiful future that puts all these issues to rest? Well, we've only had one go on the new Shimano hydraulics thus far: a 1h45 grind up Mt Etna where they weren't required at all, followed by a 16-minute descent back down where they most assuredly were. Here's what we found.

Form: the lever feels the same as a Di2 lever, and by extension a Dura Ace lever; all have the same basic shape. The pivot for the disc lever is different (the cylinder doesn't pivot, of course) but the the feel of the lever is very similar. The Di2 buttons Work flawlessly and the whole thing feels polished. The aesthetic criticisms levelled at SRAM's tall hydraulic levers aren't applicable here, though the taller profile of the Red disc lever does suit some riders.

Function: there's a lot of power available through the hydraulic setup. It's noticably more the you'd expect from a rim brake and consequently you adapt your braking to pull later in the run-up to a corner. It's not really a conscious decision: you just automatically adjust.

Modulation of the power is excellent and it was a very rare occasion that I locked up the back wheel into a hairpin; this even on a descent I don't know at all.

It's possible to fade the brakes by dragging them down steeper sections. It's a predictable fade, and only really achievable by single-wheel braking. Once you're using both brakes it ceases to be an issue, and it's not an issue at all if you're prepared to attack the straights and brake fairly late into the corners.

We had a fairly significant amount of noise from the brakes on our test bikes on the descent from Etna, more so as the system heated up. Since the pads and rotors were new it's fair to asssume that this is due to the components bedding in, but we'll see how they perform for tomorrow and Wednesday.

Overall the first impressions were very positve: easy modulated, and consistent, power in braking coupled with the simplicity of Di2 shifting.

This isn't meant to be a full review of the system, just a heads up on our first findings. We'll continue to report on how the discs work over the next couple of days, and we're also looking forward to receiving a set for longer-term testing. Stay tuned for that.

Dave is a founding father of road.cc and responsible for kicking the server when it breaks. In a previous life he was a graphic designer but he's also a three-time Mountain Bike Bog Snorkelling world champion, and remains unbeaten through the bog. Dave rides all sorts of bikes but tends to prefer metal ones. He's getting old is why.

33 comments

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ajmarshal1 [414 posts] 2 years ago
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Jesus they're ugly.

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Doper [70 posts] 2 years ago
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Levers certainly look a lot better than SPAM's. Bit worried about the fade & noise though.  17

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KiwiMike [1225 posts] 2 years ago
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If you're there to test brakes, why are they making you ride up the mountain for 105 minutes to get 16 minutes of testing? Surely this case justifies a shuttle, if ever there was one.

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thebungle [103 posts] 2 years ago
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Somewhat non-plussed about discs on road bikes but after riding around in the wet for the last few days I was reminded of just how bad caliper brakes are, that's with Ultegra calipers, Swisstop pads and new cables so a decent setup.

It's a shame that for roads bikes the aesthetic isn't as sleek as perhaps we would all like it to be, it will be interesting to see if the manufacturers can figure out a way to create reliable small rotors.

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jason.timothy.jones [294 posts] 2 years ago
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KiwiMike wrote:

If you're there to test brakes, why are they making you ride up the mountain for 105 minutes to get 16 minutes of testing? Surely this case justifies a shuttle, if ever there was one.

I would be making the ride up  19

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mrmo [2088 posts] 2 years ago
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thebungle wrote:

It's a shame that for roads bikes the aesthetic isn't as sleek as perhaps we would all like it to be, it will be interesting to see if the manufacturers can figure out a way to create reliable small rotors.

Small rotors aren't really an option, for the reason mentioned about heat and fade. As it is I am a little concerned about Shimano's choice of Rotor, if a Tandem can get the larger rotors to melt!

As mentioned elsewhere, my next road bike will have discs, but not because I want them, more because that is what road bikes will come with. Also a little concerned with all the talk of Di2 and hydraulics, what is the plan for the non-di2 groupsets that most riders use?

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Al__S [1052 posts] 2 years ago
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KiwiMike wrote:

If you're there to test brakes, why are they making you ride up the mountain for 105 minutes to get 16 minutes of testing? Surely this case justifies a shuttle, if ever there was one.

Torn a little on this. One the one hand, "earn your turns" fundamentalism runs deep.

On the other, shuttling up, and alternating between the disc bikes and the closest possible equivalent rim brake set up would actually allow some proper journalistic testing.

Especially if it was pissing with rain.

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pz1800 [24 posts] 2 years ago
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I am a disc convert, wet or dry and sod the aesthetics. I commuted for a few weeks on my Pinnacle Arkose 2 with mechanical discs before going for a weekend ride on my road bike with caliper brakes. I was shocked at how ineffective they were compared to the discs. No more calipers, thanks. And since I shan't be troubling the peleton in any way, the fact that they are not yet UCI-legal is 'meh'.

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Jack Osbourne snr [475 posts] 2 years ago
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ajmarshal1 wrote:

Jesus they're ugly.

The Campagnolo ones won't be.  4

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sponican [89 posts] 2 years ago
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That man looks very nice but can we have some pictures of the actual equipment? Only one of the six pictures shows the disc & caliper and that one doesn't really give a very good view of them.

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arrieredupeleton [576 posts] 2 years ago
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So Shimano wheel out ace descender Andy Schleck to justify their hydro disc brakes. What's next Thibaut Pinot extolling the virtues of Dura Ace Air Bags?

Schleck would be an accident waiting to happen in the peloton with discs. Its an important skill knowing where and when to brake. I think he needs to master that first before relying on new tech to bail him out.

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Chris James [400 posts] 2 years ago
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If I want my dual pivots to feel like i have fantastic braking then all I need ot do is ride my cross bike with its' cantis.

When I were a lad .... Weinmann sidepulls with steel rims ... braking was virtually non existent!

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caaad10 [184 posts] 2 years ago
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Personally I really like the way disc brakes look, particularly the clean naked areas where those pig-ugly calipers used to ruin the flow of an otherwise beautiful frame.

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Yennings [237 posts] 2 years ago
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Agree it's kind of ironic that they're using Andy as spokesperson for this one but I suppose he has more experience using brakes on fast descents than the likes of Nibali do...

Look out for Wiggo waxing lyrical about Continental's new wet-weather descending tyres next...

I am all for discs on road bikes anyway. Experience to date shows they are far better at modulation, far better in typical British weather and then there's the whole wheel weight thing - easier to concentrate weight around the hub than the rims.

Not that my views matter, frankly. If Shimano, Specialized and Mavic decide they want something to happen, it doesn't really matter what Andy Schleck thinks, let alone us average punters.

Agree I'm looking forward to seeing the Campag versions, though. Although whose technology would you rather entrust with your safety on a fast Alpine descent - Italian or Japanese?

(Actually, scrub that last comment. I just remembered about Toyota's braking issues...)

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KiwiMike [1225 posts] 2 years ago
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caaad10 wrote:

Personally I really like the way disc brakes look, particularly the clean naked areas where those pig-ugly calipers used to ruin the flow of an otherwise beautiful frame.

<- THIS.

Recently I've been ogling the new Genesis Day One, thinking that getting rid of all the calipers, mechs and rings makes for a damn good looking machine, for all weathers, next-to-no maintenance, etc etc.

Sorry disc doubters, you are losing the argument rapidly...

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dicktate [11 posts] 2 years ago
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If in your piece tomorrow you could opine on Shimano using center lock disc mount versus ISO I would be grateful  7

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Bike Swanky [44 posts] 2 years ago
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Being equally happy on a mountain bike or a road bike, I'm happy to hear that disc brakes are making more of a presence in the tarmac arena.

However, riding in the pouring rain, like we were this Sunday, highlighted a potential issue - the guys with disc brakes are going to stop a lot quicker than the guys without.

Could make for some interesting club dynamics  1

As it was, the club run on Sunday was 100% rim brakes, and we still had a rear end bump in the line. I know this because it was me!

I was avoiding some eejut in a ford focus who thought that it would be sensible to try to pass a line of cyclists where there was a pedestrian sanctuary island in the middle of the road. I had to brake to avoid him and the rider behind couldn't stop in time and we collided.

Fortunately, neither of us came off, but either one of us could have ended up under a car very easily  40

Anyway, it's likely to happen more often when disc brakes come in.

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Jack Osbourne snr [475 posts] 2 years ago
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caaad10 wrote:

Personally I really like the way disc brakes look, particularly the clean naked areas where those pig-ugly calipers used to ruin the flow of an otherwise beautiful frame.

I much prefer the look of calipers, but then I ride with beautiful Campagnolo stuff.  8

I'll grant you there are some fugly brakes out there though.

Performance is a no brainer though. I have discs on my fast commuter and they allow me to cane it along city streets in a way that I could only dream of doing with any degree of safety with rim brakes.

Downhill open road racing style braking is a skill that some have and others don't. I'm torn as to there perhaps being a competitive element of racing at risk if the UCI adopt disc for road racing.

For mere mortals like me who are still crap going downhill after 25 years on the road, they should be compulsory!

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ttekkv [36 posts] 2 years ago
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One thing that we've been hearing on a more or less constant basis is that the switch to discs is market driven, and not something that's particularly interesting the pro cyclists. That being the case it was certainly interesting to hear Andy Schleck, who's been present at the launch.

Stopped reading at this point.

Oh a pro was there taking about products. Well there's certainly no market driven forces here then. No pro would ever lower himself to using and promoting whatever they're paid to.

I'm certainly not having a go at pros pushing stuff, or cycling websites pushing stuff - everyone's gotta make their money. But if I read this correctly, the case is being made that this isn't what's happening here - when it clearly is.

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crazy-legs [795 posts] 2 years ago
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Bike Swanky wrote:

Anyway, it's likely to happen more often when disc brakes come in.

The dynamics of club riding dictate that if one person comes down, pretty much everyone else will too. That's why you have hand signals and group riding is a skill that clubs teach.

In a situation as you describe where you've got emergency braking, you're going to have shunts no matter what.

I really wish people would stop trotting out all the same old cliches.
We went through this with the upgrade from single pivot to dual pivot and on MTBs exactly the same kind of stuff was said re the upgrade from canti to V-brake to disc.

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jarredscycling [456 posts] 2 years ago
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The benefits of discs will most definitely outweigh any negligible disadvantages. Yeah riders will brake at slightly different speeds but the same is even currently true for riders on carbon vs aluminum rims in the rain. It is something that people will adjust to rather easily I think

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arrieredupeleton [576 posts] 2 years ago
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It seems SRAM showed its hand too early then. It's abundantly clear to me that Campag and Shimano knew they had to work out the electronic shifting puzzle before the move to hydro. SRAM's now stuck with fugly hoods and no e-option. Will be interesting to see where they go next. Maybe improving the reliability of their shifters - the Rival shifters in particular have a bit of reputation apparently.

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robert.brady [155 posts] 2 years ago
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arrieredupeleton wrote:

SRAM's now stuck with fugly hoods and no e-option. Will be interesting to see where they go next.

Rumour has it they will go down the hydro shifting route. I think it's Cervelo who are making frames compatible with hydro shifting lines so someone must be planning it. With Shimano and Campagnolo putting their eggs in the electronic basket, that realistically leaves SRAM.

Rob

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mikeprytherch [223 posts] 2 years ago
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How can we talk about issues on club rides, does every calliper brake perform the same, if so why bother with these expensive brakes and pads, just use any old crap. Every bike stops differently, just like every car, I don't crash into everything on the road because they have different brakes, you ride with your eyes and by feel, you know how long it will take you to stop, disc brakes on the guy in front should make no difference, if you wait for the guy in front to do something you are likely to crash no matter.

I did a charity ride on Sunday in really crap weather, 80k of non stop rain, it was horrible and my brakes (Ultegra) where utter shit in the wet.

Bring on disc brakes, sod aesthetics, I value my life and my bike, anything which stops me quicker is good in my view, can't wait to upgrade.

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fukawitribe [1825 posts] 2 years ago
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thebungle wrote:

As mentioned elsewhere, my next road bike will have discs, but not because I want them, more because that is what road bikes will come with.

They're not compulsory and the manufacturers that are using them already seem to all be offering a choice of disc or caliper. The chances of any bike producer deliberately ostracising a sizeable section of it's target audience to make a point
about any particular piece of technology are also, probably, approximately zero. The chances of there being no desirable road bikes out there without discs, in the foreseeable future, are almost certainly less than that.

thebungle wrote:

Also a little concerned with all the talk of Di2 and hydraulics, what is the plan for the non-di2 groupsets that most riders use?

Existing plans include SRAM and mechanical/hybrid pull discs plus any other non-electrical set-ups that appear in the future. This is likely to only be an issue if you want it to be.

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richdirector [68 posts] 2 years ago
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I use discs on my mtb and love them although my road bike has metal rims and is generally clean so never had an issue with rim brakes. As any mtb knows you need to bed the pads in - one descent pedalling with brakes on then spray water from your bottle on them and bam done. Perfect bedding and no squeaking ever. I am sticking with rims for now and will just pick up some fleabay bargains from all those MAMILS jumping to discs

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sidesaddle [90 posts] 2 years ago
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Anyone who has ever ridden a 70's motorcycle knows, possibly at great cost, that discs alone are not the answer to the rain  2

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mustard [73 posts] 2 years ago
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robert.brady wrote:

With Shimano and Campagnolo putting their eggs in the electronic basket, that realistically leaves SRAM.
Rob

Or Magura.

Anyway, what am I seeing on the two bikes nearest the camera in picture 5, did the have some standard calipers to ride against the discs or something else you're not allowed to talk about yet...

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Kim Chee [33 posts] 2 years ago
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 16 oh there were no issues so long as you wore SPD cleated shoes and had SPDs brazed onto the gas and brake pedals to appropriately pull UP as needed.

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mrmo [2088 posts] 2 years ago
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fukawitribe wrote:
thebungle wrote:

As mentioned elsewhere, my next road bike will have discs, but not because I want them, more because that is what road bikes will come with.

They're not compulsory and the manufacturers that are using them already seem to all be offering a choice of disc or caliper. The chances of any bike producer deliberately ostracising a sizeable section of it's target audience to make a point

all that needs to be said is 650b.

I would have to agree with thebungle though, i don't think manufacturers are going to alienate people, just that they will move any mid to high end road bike to discs, the timescale will come down to the UCI though.

Discs have advantages, but after using them on MTBs for 10? years i can honestly say they do have a lot of problems. Go to any MTB forum and read the number of posts about bleeding hydro brakes for a starter.

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