Disc brakes and road bikes: what does the future hold?

If you’ve been paying any sort of attention to what the major manufacturers have been doing in the past year or so, you’ll notice that disc brakes are becoming more of a fixture on road bikes. This is not a passing fad.

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If you’ve been paying any sort of attention to what the major manufacturers have been doing in the past year or so, you’ll notice that disc brakes are becoming more of a fixture on road bikes. This is not a passing fad.

SRAM and Shimano released hydraulic disc brakes earlier this year and if this year’s Interbike and Eurobike are any indication, we’re starting to see high-end road bike manufacturers take disc brakes seriously.

So is it only a matter of time before we see the pros rolling around with bikes equipped with disc brakes? Are all your sets of wheels going to be rendered obsolete in the coming years? And what’s stopping all this from happening now? We spoke with the UCI as well as industry experts to find out what the future holds.

It’s pretty clear that the industry wants disc brakes to take off. They are a new means of differentiation and they require new wheels, new hubs and new frames, all of which means more stuff for consumers to buy. But it’s not only that.

I’ve had the pleasure of riding a Specialized Roubaix S-Works with disc brakes in recent weeks (review coming tomorrow) and I was astounded at the braking performance advantage.

For those of you familiar with the transition to mountain bike discs, you’ll remember how this technology revolutionised mountain bike riding. Braking is simply better compared to traditional brakes and there’s less rim and brake-pad wear. Even in dry conditions the braking is noticeably better and more reliable on discs. The industry likes to describe this as braking modulation — the way the braking “feels” and how much fine control you have when squeezing the brake levers.

Having disc brakes also also means that heat dissipation on the rims is no longer a problem — something that is an issue with carbon clinchers. With disc brakes you can have all the benefits of a carbon clincher, but with a lighter rim and better and more predictable stopping power. Also, when a wheel comes seriously out of true, braking isn’t affected when you’re running disc brakes.

Industry impressions

Shimano launched Ultegra disc brakes for road bikes earlier this year. I asked Shimano’s Australian Product Manager, Troy Glennan, where he thinks disc brakes are headed when it comes to road bikes. Note that Troy’s opinions don’t constitute an official statement from Shimano; they’re just his thoughts about where things are headed.

[ct_blockquote_start no_underline=1] “Rim brakes will always be there, but the biggest factor is what the UCI does with it. From a safety point of view, I’m not sure that’s going to happen for a while. When you’ve seen guys crash mountain bikes and put a rotor through their knee, it’s not pretty. Throw in some of those crashes you see in sprint finishes on the road …

It will come down to a point where the UCI would have to make a rule where everyone uses one braking system or another (everyone uses discs, or everyone uses calipers) because of different stopping capabilities.

You’ve seen bike companies produce bikes like the Specialized Roubaix or BMC Gran Fondo — you can see that it’s not aimed at the race market as of yet. This is where it’ll be targeted at for the next few years.

Shimano doesn’t see this as just a fad and I think that there’s a spot in the market for a completely different category of bikes using disc brakes. [But] I can’t see caliper brakes vanishing and becoming obsolete.” [ct_blockquote_end]

I also spoke to Rob Eva, Head of SRAM Australia, about the future of disc brakes and his take was quite different to Troy’s:

[ct_blockquote_start no_underline=1] “I disagree that disc brakes will only be part of a category [of road bikes]. Do you see a ‘category’ of mountain bike that only had disc brakes? No – you can’t find a mountain bike with rim brakes anymore.

I see all bikes evolving to disc brakes. I remember back in my mountain bike days there [was] the same resistance. I think the change to road disc brakes will be swifter and more strategic than it was to mountain bikes.

The reason I think that is because carbon rims (full carbon clinchers) are such a safety issue with all these newcomers not knowing how to brake. Essentially it’s become a safety issue to run a rim brake on a carbon braking surface. The braking power is not good enough.

People who criticise disc brakes have not ridden them. For those people who want to stand by ‘tradition’, I say that there’s lots of things that are ‘traditional’ in road cycling. Taking drugs is ‘tradition’, but you know what? That has to change as well.

Tradition doesn’t mean anything when it comes to performance and safety. We’re trying to take weight off the tyres, off the tubes, off the rims, off the wheels, and it’s got to give somewhere. I think we’ve come to the point where it’s starting to give, and we gotta put that weight back, be safer, and put a decent set of brakes on that will work.”[ct_blockquote_end]


So what does Rob Eva think about the idea that a shift to disc brakes is merely an industry push to get cyclists to spend more?

[ct_blockquote_start no_underline=1]“We’re not forcing anyone to upgrade to disc brakes. Yes it is a bit of a fashion, but it’s a necessary performance fashion. It’s a huge advantage that I think is worthwhile. We’re designing disc brakes, but we’re not the ones who make the decision to put them on every frame. It’s the frame manufacturers who come to us and ask for discs.”[ct_blockquote_end]

Disc brakes and the UCI

The UCI’s technical regulations currently don’t allow disc brakes to be used in road races. We spoke with the UCI’s Technical Collaborator Johan Kucaba about whether that’s likely to change any time soon.

[ct_blockquote_start no_underline=1]

From the UCI point of view, the disc brakes are still considered as a technical innovation, and therefore they are still not allowed in road competitions. However, for some time now, we follow the development of these new brakes, and the subject is discussed within the UCI Equipment Commissions.[ct_blockquote_end]

Johan was quick to point out that most of the current road bikes that use disc brake are using brakes designed for cyclocross or MTB and that road-specific disc brakes are needed to handle the unique nature of road cycling.

[ct_blockquote_start no_underline=1]“The main differences and challenges to be resolved are:

• higher speed
• longer braking time
• higher temperature accumulation
• bigger disk which means bigger safety issue in case of crashes
• braking behaviour that may block the wheel and make the bike slip
• difference of braking performance between disc brakes and rim brakes that may cause crashes inside the peloton.”[ct_blockquote_end]

Until now the UCI has only received one request from a manufacturer to allow disc brakes in road racing. After careful consideration from the Equipment Commission, the braking system was rejected because it “did not fulfil … all the above requirements and did not provide all the necessary guarantees for safety”.

But, as Johan reiterates, the UCI is receptive to the development of disc brakes for road racing.

[ct_blockquote_start no_underline=1]“We are therefore in contact with manufacturers, and follow the development of these braking systems. Moreover, we encourage the industry to develop these braking systems.

The decision to allow disc brakes in road competitions could be taken when a manufacturer will provide us the sufficient elements that prove that his brake system fulfil to all requirements and that it is adapted to the use in road competitions.”[ct_blockquote_end]

At that time, the UCI Technical Regulation will need to be updated, meaning a one-year delay before they’d be usable on the road. And to allow the industry to adapt and ensure fairness for all teams and riders, an extra one-year delay would likely be applied.

“With the Olympic year in 2016 (and therefore no modification in the regulation that year), it is unlikely that the disc brakes are allowed in road races until 2017”, Johan said.

Shimano Ultegra disc brake.
Shimano Ultegra disc brake.

Rob Eva from SRAM argues that the decisions made by the UCI will have little effect on everyday cyclists.

[ct_blockquote_start no_underline=1]It really doesn’t matter what the UCI says. They’re only a small part of cycling and there are a lot of people out there who don’t care what the UCI is nor do they give a damn. They just want to ride their bikes. On the road racing side of things, the UCI will play a part in it, but it’s not going to be a huge part.”[ct_blockquote_end]

In many ways, Rob is right — there’s nothing stopping manufacturers from making disc-brake-equipped road bikes for the consumer market, and nothing stopping riders from doing club rides, gran fondos or other non-UCI-sanctioned events with disc brakes.

Other challenges

Even if disc brakes were to be introduced into the pro peloton next year — which we know they won’t — there’s still a handful of issues that need to be resolved.

For a start, there is no industry consensus or standard on what size of disc brakes to use. Shimano’s rotors use the company’s ICE Technology which allows a 140mm rotor to be used (front and rear) without worrying about heat dissipation. Rob Eva from SRAM recommends a 160mm rotor on both front and rear (SRAM offers both 140 and 160mm rotors). Ultimately though, the frame manufacturer is the one who specs the rotor size.

And then there’s the aero-craze going on at the moment in the industry. The trend right now is that everyone is producing aero road bikes (not to mention aero helmets, shoes, jerseys, etc). If you go and stick a disc on an aero bike, then any aerodynamic advantage is likely jeopardised. At the highest level, all the manufacturers are incorporating integrated frame braking to get the best aero advantage.

Final thoughts

Road racing is steeped in tradition and I think it’s safe to say that roadies are not early adopters of new bike technology. Mountain bikers and triathletes are the exact opposite. Personally, I’m a big supporter of innovation because it is innovation that eventually leads to progress.

Just like Di2 electronic gearing or the iPad, disc brakes for road bikes don’t appear to be filling a real need — existing braking technology does a very good job. But like Di2 or the iPad, once you start using disc brakes, you’ll wonder how you did without them.

What do you think? Are hydraulic disc brakes the next big advancement in road bike technology? Or is this solving a problem that doesn’t exist?

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