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Trek trials disc brakes at the Vuelta - and reaction is positive from the pro riding them

"I think that this is the future," says Markel Irizar after racing Vuelta stage on disc brakes

Disc brakes are now in the professional peloton, albeit on a trial basis. The UCI has allowed each team to test disc-equipped road bikes in selected races during August and September. We’ve seen a few already, and on stage six of the Vuelta a España, Trek Factory Racing’s Markel Irizar raced aboard a Trek Domane with Shimano hydraulic disc brakes.

It was a stage described afterwards as being a fast and hard day with a lot of undulation, up and down all the time with more climbing than had been expected. It was during these demanding conditions that Markel Irizar embarked on a disc brake trial. Trek has shared his (mostly positive) reaction to riding disc brakes.

- Disc brakes to be permitted in peloton in 2017

"Of course it’s a little more heavier and to change the wheel [in case of a puncture] is a little more difficult, but I think that this is the future,” commented Markel Irizar on riding disc brakes in a professional race for the first time.

“Many riders have been concerned about safety, like when it is really hot and if you crash it can cause damage by cutting someone or even burning. So I think for the future Shimano may have to look at covering the disc, and once we are 100 percent sure that nothing can happen, then I think everyone will use it because for sure in the rain the [braking] difference is going to be huge.

“Today in the heat already the difference was already really big  I think it’s the same when the electronic shifting came, it had a negative reaction at first, and now everybody loves it. I think that in a couple of years for sure everyone will love it. This is the first step, of course, there are some things we can improve, but this was Shimano’s goal, to have it tested in races to have the information. I will try it again in two days. I think with some small changes that this will be the future.”

- 2015's hottest disc-equipped road bikes

We don’t know if he first used them outside of a pro race to acclimatise to them, or whether this was his first experience on disc brakes. It is clear from his reaction that the risk of a hot rotor scalding a body part in the event of a crash is still a big factor facing adoption among the pro ranks. However, covering the rotor, which he suggests as a solution, would only add weight back to the system, when there is already a weight penalty. Unless Shimano could develop an aerodynamic cover that would kill two birds with one stone?

He was riding a Trek Domane, which has been available with disc brakes for some time. The longer wheelbase and chainstays of that model makes it easier to add disc brakes. The shorter chainstays on the Emonda and Madone raise chainline issues with the wider rear axle that is necessary to accommodate the disc rotor. Specialized has designed a specific freehub to get around this problem, while the new Cervelo R3 Disc has a custom FSA chainset with the driveside crank arm placed a few millimetres further outboard.

- Trek gear up for the disc brake revolution with new Domane Disc

An obvious issue with disc brakes on road bikes at the moment is one of wheel changes. The Domane uses thru-axles at both ends, 15mm at the front and 142x12mm at the rear. The Team Sky Pinarello Dogma F8 Disk with Shimano disc brakes we spotted being raced last month uses conventional quick release axles. 

That raises obvious challenges for the neutral support, so any puncture or mechanical would have to be resolved by a complete bike change. To be fair, complete bike changes are fairly common when the team car is near or it’s a pivotal moment in the race. Races have also been lost as a result of slow wheel changes though, so it's clearly a problem in need of a solution. And then there’s the issue of rotor size too. Will the UCI step in and issue a standard?

So there are issues to overcome, it's clearly early days for discs in the peloton, and these trials are a good way to soft launch disc brakes into the pro ranks. Let's see who is next to test disc brakes in a pro race. There's the Tour of Britain starting soon...

David worked on the road.cc tech team from 2012-2020. 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, and you can now find him over on his own YouTube channel David Arthur - Just Ride Bikes

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25 comments

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andyspaceman | 9 years ago
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Regarding the sharpness issue, I had a look last week at the disks on all the bikes in my garage, as well as the old rotors sitting in the spares box. Reckon there's about 15 years worth of MTB products represented there, mostly from Shimano, but a few other aftermarket manufacturers too.

The laser-cutting process used in disk manufacture can definitely result in some very sharp edges. A large scar on my brother's thumb is testament to that, where a workshop incident resulted in a big flap of skin being taken almost clean off the tip.

But the design has definitely improved in recent years, with the 'spokes' now largely being made of a separate forged piece of alloy with smooth edges, and the steel braking surfaces seeming to be less sharp than they once were. I'm not sure if they're grinding them, or cutting them using a different method, but they're not the razors they used to be.

Heat is a legitimate concern - I have met a mountain biker who has a nice 'brand' on his left calf which was a result of a crash at the bottom of a long descent. Some kind of lightweight guard might help here, and if designed with angled vents could even help channel cooling air onto the rotor. It's worth a thought.

With regard to the axle standards, the Eurobike displays seemed to suggest that 100x12 front and 142x12 rear is looking like the way manufacturers and teams are now leaning. A common standard in the peloton is a must, and the rest of the industry will follow. But from a consumer perspective, 100x15 front and 135xQR rear is going to be around for a while to come, simply because of it's long term use in the MTB industry. Those hubs aren't going to disappear anytime soon if you're happy with handbuilt wheels.

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croissantlune | 9 years ago
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Putting an aerodynamic cover on a disc rotor would rather undermine the heat dissipating abilities of it.

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Grizzerly | 9 years ago
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One of the regular causes of crashes in the peloton is tyres losing grip under braking on wet roads. The carnage in La Course on the Champs Elysee was a clear example of this. Imagine how much worse it will be when everyone uses disc brakes.

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crazy-legs replied to Grizzerly | 9 years ago
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Grizzerly wrote:

One of the regular causes of crashes in the peloton is tyres losing grip under braking on wet roads. The carnage in La Course on the Champs Elysee was a clear example of this. Imagine how much worse it will be when everyone uses disc brakes.

Watch this:
https://www.youtube.com/watch?v=uHFSSXOSnxs
and this:
https://www.youtube.com/watch?v=JplymlruPZ8

then stop talking rubbish!

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Gasman Jim | 9 years ago
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The chain-line issue could be easily sorted by reverting to good old 10 speed!

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monty dog | 9 years ago
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Chainrings also do a pretty good impression of a circular saw when encountering soft fleshy bits - or are we going to ban them too?

I built my first disc-roadie over 10 years ago - the techs at big bike must be pretty cr@p if they're still working out the details like chainline and heel-clearances.

I'll stick to QRs for CX if it means quick wheel changes - fast rear wheel changes with a through-axle need 3 hands and easy to bork the thread if hurried. Rode an untabbed fork with discs for years and haven't died - Darwinian principles should sort out the rest.

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levermonkey | 9 years ago
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Are brake rotors more dangerous than what is already on the bike? No.

Heat build up.
Most of the rear rotor is guarded by the rear triangle of the frame so contact in the event of a crash is remote. The front rotor may cause more of a problem as it is more exposed. However, you would have to drag the brakes for miles in order to creat enough heat in the rotor to cause serious burns.

"Bacon Slicer" Effect.
The rear rotor is guarded and front wheel carries less momentum than the rear and stops fairly quickly when in contact.

Now that we have looked at the 'danger' posed by disc brakes let's look at what is already there.
Put your bike on a work-stand and spin the rear wheel up. Now shove your hand into the wheel. Get a friend to collect your severed fingers and drive you to the hospital.

Can we now stop this bollocks about how more dangerous disc brakes are please. Thank you.

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surly_by_name | 9 years ago
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"It is clear from his reaction that the risk of a hot rotor scalding a body part in the event of a crash is still a big factor facing adoption among the pro ranks."

This is tosh. The chances of being burnt by a rotor in a crash are, I would suggest, absolutely tiny and the chances of having anything "sliced open" must similarly be vanishingly small. And irrelevant next to the road rash a crash is almost certain to produce. I realize road cyclists are hidebound but I hadn't appreciated just how superstitious they really are.

"However, covering the rotor, which he suggests as a solution, would only add weight back to the system, when there is already a weight penalty."

There isn't a net weight penalty. Manufacturers are able to build bikes that come in below the UCI weight limit (which is still at 6.8kgs I think) with ease, hence some rider having to add weights to their bikes. Less weights, more braking = same 6.8kgs. And that's even before you reduce rim weight because you don't need it to withstand braking forces/heat.

Is this a deliberate strategy of misinformation?

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cub | 9 years ago
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I've argued against whether disc brakes are that much better that rim brakes, they probably are, especially in the wet, but now I have a new question:

Do better brakes cause crashes?

Track racing has never allowed brakes because its reasoned they'd cause more crashes than they would stop. Thinking back to the tour, major crashes there were on straight roads where brakes weren't needed at all.

If you compare two extremes, one where the only braking is back pedalling and another where you can stop near instantly, if you were riding in two groups of each which do you think you would be more likely to end up riding into the back of someone?

Faster braking means you have to react faster and humans aren't evolving better reaction times.

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surly_by_name replied to cub | 9 years ago
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cub wrote:

Do better brakes cause crashes?

Guns don't kill people. People kill people.

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bobinski | 9 years ago
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Wheel changes will be a real problem though until agreed standards develop.
I find that whenever I have to remove and then reattach the disc wheels on my advanced pro I seem to end up with some degree of disc rub. I can be a bit of a klutz but I didn't have a similar problem with caliber brakes. I am using shimano hydraulics. Can any bike mechanics on here recommend a fail safe way to reattach a wheel,minimising the risk of disc brake rub?

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surly_by_name replied to bobinski | 9 years ago
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bobinski wrote:

whenever I have to remove and then reattach the disc wheels on my advanced pro I seem to end up with some degree of disc rub... I am using shimano hydraulics.

Yes, that's why mountain bikes went to thru axles - it is a more reliable way of putting ensuring the rotor goes back into the same place every time thus reducing the risk of the dreaded turkey gobble.

bobinski wrote:

Can any bike mechanics on here recommend a fail safe way to reattach a wheel,minimising the risk of disc brake rub?

Get a frame with thru axles.

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JonD replied to surly_by_name | 9 years ago
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surly_by_name wrote:
bobinski wrote:

whenever I have to remove and then reattach the disc wheels on my advanced pro I seem to end up with some degree of disc rub... I am using shimano hydraulics.

Yes, that's why mountain bikes went to thru axles - it is a more reliable way of putting ensuring the rotor goes back into the same place every time thus reducing the risk of the dreaded turkey gobble.

bobinski wrote:

Can any bike mechanics on here recommend a fail safe way to reattach a wheel,minimising the risk of disc brake rub?

Get a frame with thru axles.

Im not sure that was the main motivation - I think the original selling point was primarily adding to fork stiffness, some brake arches at the time were bolt-on, plus some forks were long travel and/or USD, it also gets around the issue of loosening qrs. Qr and thru axle (eg qr20) have been running in parallel since the late '90s, it's only in recent years or so that thru axles been more common, dunno how much longer travel hardtails have to do with that..

Some interesting pics here fwiw:

http://m.pinkbike.com/news/Marzocchi-Forks-Through-the-Years-2013.html

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Carton replied to JonD | 9 years ago
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JonD wrote:
surly_by_name wrote:
bobinski wrote:

whenever I have to remove and then reattach the disc wheels on my advanced pro I seem to end up with some degree of disc rub... I am using shimano hydraulics.

Yes, that's why mountain bikes went to thru axles - it is a more reliable way of putting ensuring the rotor goes back into the same place every time thus reducing the risk of the dreaded turkey gobble.

bobinski wrote:

Can any bike mechanics on here recommend a fail safe way to reattach a wheel,minimising the risk of disc brake rub?

Get a frame with thru axles.

Im not sure that was the main motivation - I think the original selling point was primarily adding to fork stiffness, some brake arches at the time were bolt-on, plus some forks were long travel and/or USD, it also gets around the issue of loosening qrs. Qr and thru axle (eg qr20) have been running in parallel since the late '90s, it's only in recent years or so that thru axles been more common, dunno how much longer travel hardtails have to do with that..

Some interesting pics here fwiw:

http://m.pinkbike.com/news/Marzocchi-Forks-Through-the-Years-2013.html

Agree with you on stiffness/durability being the main motivation behind thru-axles for MTBs, but thru axles for road bikes do seem to have popped up mostly due to the brake rub issue they incidentally solve.

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CXR94Di2 replied to bobinski | 9 years ago
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bobinski wrote:

I am using shimano hydraulics. Can any bike mechanics on here recommend a fail safe way to reattach a wheel,minimising the risk of disc brake rub?

I dab the brakes, the pistons then realign, job done  1

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bobinski replied to CXR94Di2 | 9 years ago
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CXR94Di2 wrote:
bobinski wrote:

I am using shimano hydraulics. Can any bike mechanics on here recommend a fail safe way to reattach a wheel,minimising the risk of disc brake rub?

I dab the brakes, the pistons then realign, job done  1

I shall try and let you know how I get on!

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mikroos | 9 years ago
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@joulesr1975 - to be fair, there are very few cyclists who are as infuential as Spartacus and can actually choose what they ride. Most of them have only limited choice and everybody knows that.

I totally agree, however, that there were many unjustified statements from riders who have never actually used disc brakes.

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Paul J | 9 years ago
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The chainline issue is one I've heard from an engineer at a major components vendor. Not just the chainline, but the chain stays. To keep a racy short wheelbase with the wider hub of a disc brake on the rear can lead to heel clearance issues. So to get discs on race bikes may require compromising on wheelbase and speed of handling.

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surly_by_name replied to Paul J | 9 years ago
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Paul J wrote:

The chainline issue is one I've heard from an engineer at a major components vendor...

And on Road.cc - repeating what Spesh told them. Which might be true but they (Spesh) claim to have solved it with a new hub standard. Which will no doubt elicit groans of "not another standard" but at least they are trying.

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Pub bike replied to Paul J | 9 years ago
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Paul J wrote:

The chainline issue is one I've heard from an engineer at a major components vendor. Not just the chainline, but the chain stays. To keep a racy short wheelbase with the wider hub of a disc brake on the rear can lead to heel clearance issues. So to get discs on race bikes may require compromising on wheelbase and speed of handling.

Could use a disc brake on the front wheel only and stick with rim on the back.

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cat1commuter | 9 years ago
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I think riders being cut by rotors is a bigger issue than burns. I wonder if the edges of rotors have to be so sharp. Couldn't they be given a round profile?

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joules1975 | 9 years ago
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Rotors hurting someone in a crash .... no-one seems too bothered about a big circle with very sharp teeth in the form of a chain-ring!

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cat1commuter replied to joules1975 | 9 years ago
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joules1975 wrote:

Rotors hurting someone in a crash .... no-one seems too bothered about a big circle with very sharp teeth in the form of a chain-ring!

I guess most of the time in pileups the big chainring is covered by the chain.

The teeth on a chainring don't have quite the same bacon-slicer effect as a brake disc.

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Sanderstorm | 9 years ago
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My experience with thru axles and discs off road is that once the wheel is in, it's all lined up and easy to thread the axle in. So there's less faff and annoyance than my road frame which often needs nudging around and moving the brake callipers. I wouldn't be surprised if when the pro mechanics get handy at wheel changes with thru-axles, they'll be just as quick or quicker than QR systems.

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Sanderstorm | 9 years ago
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My experience with thru axles and discs off road is that once the wheel is in, it's all lined up and easy to thread the axle in. So there's less faff and annoyance than my road frame which often needs nudging around and moving the brake callipers. I wouldn't be surprised if when the pro mechanics get handy at wheel changes with thru-axles, they'll be just as quick or quicker than QR systems.

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