Analysis: Do disc brakes belong in the pro peloton?

Disc Tour de France

Weight Issue Disc Brake Defy

Despite a small weight penalty compared to traditional rim brakes, Giant choose to make significant investment in disc brake technology with its new Defy endurance road bike line. Photos by Chris Milliman

Giant stuck with traditional quick release set-ups for its new Defy line. Other manufacturers have opted for thru-axles, some 12mm, some 15mm. Some use both, such as the new Mares cyclocross bike from Focus. But variances like that simply don’t work in the professional peloton, where neutral service providers such as Mavic need to be able to take care of nearly 200 riders, but don’t have the cargo capacity to carry dozens of different set-up wheels.

“Right now there are multiple conversations happening between a few of the big brands and everyone is talking the same talk,” explained Giant’s Swanson. “We all know that for the technology to be embraced by the highest level of racing, there has to be a consistent standard and it needs to have quick release functionality so that you can change wheels on the fly.”

Swanson‘s choice would be 12mm thru-axles. “That gives you some added stiffness so you could remove some of the extra frame material from the fork leg,” he said. “That will help keep the weight penalty in check.”

Heretofore, that weight penalty might not necessarily have been a major issue in the pro peloton. As it is right now, most team mechanics are forced to add otherwise-unnecessary weight to bikes just to stay within compliance of the UCI’s 6.8kg (14.99 pounds) weight limit. But with new bikes such as Trek’s ultra-light Émonda line coming to market, perhaps that rule could see amendments soon as well.

“Bikes should weigh however much [the manufacturer] wants them to weigh, provided they have all the commercial safety certifications,” said Swanson. “If it is fit enough for sale it should be fit enough to race.”

To wit, the Trek Émonda SLR 10 has a claimed weight of just 10.25 pounds, and a size 60cm test model Émonda SLR 8 equipped with alloy wheels that just showed up at the RoadBikeReview offices weighed 14.1 pounds without pedals. But no bikes in the Émonda line come spec’d with disc brakes.

“We don’t see a lot of demand on race bikes,” said Trek road product manager Ben Coates, whose company does spec discs on some of its Domane endurance bikes.


Adoption of disc brakes in the pro peloton will require that the industry adopt some kind of axle standard in order to make wheel changes fast. Photo by Graham Watson

But might that attitude change if the UCI changed its tune? Swanson believes so, and says the recent regime change at the UCI has resulted in more openness to technology rule changes. “[Since Brian Cookson replaced Pat McQuaid as UCI president] the attitude has been much more positive and progressive, which is really important to the industry,” Swanson said. “Sometimes manufacturers aren’t willing to pull the trigger on new technology because you need racing as a marketing vehicle.”

Clearly, though, disc brakes are not falling into that well. Like Giant, Specialized has gotten behind the idea despite the lack of UCI approval, launching multiple rotor-equipped bikes, including some Tarmac models, which made it one of the first manufactures to spec disc brakes on a race bike rather than only endurance geometry frames.

“We are full gas on disc brakes,” said Specialized spokesman Chris Riekert. “It’s something we see as more than just a wet weather advantage. There’s so much more available braking power and when you mix the race geometry of the Tarmac with that extra braking and you have a really diverse weapon. At the same time, I think it will take a while before it catches on in the pro peloton. When the weight comes down and you have enough wheel options, that’s when you’ll see that switchover.”

“Right now I just don’t see disc brakes being to the point where they are ready for racing application,” added Jonathan Vaughters, general manager of the Garmin-Sharp team, who race on Cervélo, which has yet to offer a disc brake-equipped road bike. “But I’d guess all those bugs get worked out in the next few years. Than at that point you can concentrate on making the rim better structurally and more aero without worrying about the braking surface. Right now it seems like wheels either have a great braking surface but are kind of heavy, or they are super aero and light with a shitty braking surface. When you bring all that together, things will change.”


Team cars can only carry so many spare bikes and spare wheels.

Most argue when that change does comes, it must be universal across the pro peloton. The notion of some riders with disc-equipped brakes riding in close proximity to others who are still running rim brakes makes people nervous.

“If everyone doesn’t have them then you’re going to have a lot more crashes because they stop differently than normal brakes,” said BMC Racing’s general manager Jim Ochowicz, whose team finished fourth in the team standings at this year’s Tour. “If we do it, it has to be all in, not half half.”

Swanson counters that International Olympic Committee rules could make an all-or-nothing proposition untenable. “IOC rules say you cant have mandatory technology like that so close to the Olympics, and 2016 is an Olympic year. So it might have to be a mix at first,” he said. “But for me the larger problem is that right now we are still using modified mountain bike technology. Once UCI approval comes, you’ll see all the manufactures focusing on road and that will get the weights down quickly and adoption will follow.”

It would appear then that disc brakes are eventually coming to the pro peloton. But do they belong there? We give the last word to NetApp’s Dempster, whose sentiment, while not universal among his pro tour peers, is shared by many. “I’ve ridden mountain bikes with disc brakes and you just stop faster,” he said. “I just don’t see why stopping faster would be bad.”

What do you think? Do disc brakes belong in the pro peloton? Sound off in the comments section below »
About the author: Jason Sumner

An avid cyclist, Jason Sumner has been writing about two-wheeled pursuits of all kinds since 1999. He’s covered the Tour de France, the Olympic Games, and dozens of other international cycling events. He also likes to throw himself into the fray, penning first-person accounts of cycling adventures all over the globe. Sumner, who joined the / staff in 2013, has also done extensive gear testing and is the author of the cycling guide book "75 Classic Rides: Colorado." When not writing or riding, the native Coloradoan can be found enjoying time with his wife Lisa and daughter Cora.

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  • DrSmile says:

    Are we going to have spec bikes like cars in Indy or Nascar to make this work? I’m sure Specialized would pay a pretty penny to be the bike of the peleton for 2016. I’m sure there are lots of corporate opportunities here! Let the market decide I say… while I stop watching entirely and go ride my BSA bracketed aluminum rim braked “oldie.”

  • one1speed says:

    Interesting, both good points of view. I do think they make a lot of sense in wet conditions. especially on long descents. Don’t be fooled, they aren’t going to stop crashes from happening.

    In some ways, I see this purely as a vehicle to try to sell more bikes. Road bikes have been raced for over 100 years without them, and with everything becoming so much lighter and rim brakes becoming better, I certainly don’t see them as necessary.

    This is one of those things that I would call change, more than progress.

  • EmptyBee says:

    The killer rotors image is just way too much of a stretch! I’ve been loving disc brakes for years on my mountain bikes and can’t wait until I can run them on my road bike too.

  • Jody43 says:

    For me it comes down to wanting tubeless. A tubeless tire, spread out over a wider rim, can be run at a more comfortable pressure than a narrower traditional racing tire. According to schwalbe their ultremo tubeless has the lowest rolling resistance of all their tires. It is no secret that rim brakes on carbon rims, which don’t dissipate heat, lead to tires overheating and blowing off the rim on long descents. Disc brakes are what are needed to bring all this together so we safely run carbon rims with the most efficient tires. Stopping in a controlled, quicker manner is a definite bonus.

  • cyclist says:

    As pointed out the only challenges are axle standards and re-learning to do a wheel change. The rest is just resistance to change: weight, too much stopping power, dismembering fingers – really?? I would think bladed spokes would be just as dangerous. I think it is pretty cool that we consumers can ride better technology than the pros, i.e. lighter bikes and have disc brakes.

    • Luis says:

      Funny how that is. No auto driver drives a better car than a F1 racing vehicle. But in Cycling a matures ride better bikes than the pros. The UCI is part of that problem. I understand specs have to be equal but we need technology to help the riders and make racing safer as well as faster. Keeping new technology at bay is a conservative view that holds racers back. I remember when Scott had a bike that weighed 890 grams and the next one up was 1095. The tour made riders use the heavier bike. By the way that is what I ride. I am no racer by a long shot but I can handle my bike well. I enjoy riding. But if I was rich enough I can have better technology than a race team can have.

  • David says:

    How many racing crashes are due to carbon brake tracks? Disc brakes would seem to help the progress of bike technology and reduce racing crashes. Carbon rim brake tracks have always been less than desirable, unless they had an aluminum insert brake track. Hot discs would be a problem, but then so are chainrings teeth, yet disc brakes would reduce the possibility of some crashes. I believe disc brakes are inevitable in the peloton, but it will be a matter of years instead of months. Watch the bike manufacturers push for it, as another marketing exercise, to make your current high dollar bike obsolete.

  • RGRHON says:

    I’d like to see a small polished smooth bead around the circumference in case my face hits your disc, especially with road discs getting bigger (Trek just went to 160mm) due to the higher speeds of road bikes. Please also note that a rim is a 700mm disc! Also, has anyone noticed both Shimano and SRAM recalled their disc brakes due to failure? If UCI is concerned about the Pro Peloton what about all the amateur crits, like class 4-5? I thought pros were better riders with better reaction times than the rest of us? I think the UCI is wise to wait until this stuff works properly. Manu’s only care about today’s profit. UCI is really our only regulatory committee, unless the manu’s screw bikes up royally and we end up with the NTSB involved!

  • dave says:

    It does make sense for roadbikes if it makes sense for mountain bikes, in that the speeds are much higher on the road.

    But now you will have someone braking much faster, and the reaction time of the rider behind will be no faster. = more accidents.

    I personally would not have them on any bike I ride. You look at them and they bend.
    They chatter and rattle down the road. they add weight, cost, complexity.

    I think it is just a style deal. Look ma, I am just like a car!

    I would like to see wider tires mandated. They are no slower and would be alot safer.
    They would also help to bring the weight of the bike up to the 15 # mark. I am tired
    of all the crashes and carnage. This sport is too much of a gory spectacle.

  • Clarence says:


    it’s a bit lame to say that a hot rotor will do more damage than going yourself into a cliff or the fact that the rims [which aren’t similar to a disc brake at all] can’t get equally hot, or that a crankset is dangerous as well at any temperature. its way easier to make contact with a crankset or a security fence bombing a hill than actually touching a 203mm rotor like in a downhill mountain bike. now that i remember, from all the 30-40 crashes i had on my mountain bike bombing down a bike park i never experienced anything like touching a disc brake, be it deliberately or accidentally.
    yes it may sound like magic, but usually disc brake systems are maintenance free. in every sense. you just go check for any bubbles inside the hose once per year.

    people who mark “having to adjust a disc brake in mid race while hanging half body out of the car” really have no idea how a disc brake system works. you don’t need to adjust it. its an hydraulic system, it self aligns. and that’s with today’s models, imagine when we have them perfectly tailored to our road steeds. puff! another imaginary disadvantage gone.

    lets put some facts:

    rotors don’t rattle when installed on a thru-axle interface, as the latter dramatically improves rigidity and structural performance of the fork/rear triangle.

    having a disc brake system means no need of a rim brake track. on VeloNews [i think] i read the amount of aluminum used for create a structurally stable brake track on a rim is about 200-350g, while the average 160mm steel rotor weights under 200g. also, needless to say, manufacturers can expand possibilities on improving the wheel itself, without worrying about some brake pads having to press on the rim.

    using a disc brake system will transfer a considerable weight of the wheel system to the center, making the wheel more reactive since it counts with less rotational mass at the outer parts. and a 1500g reactive wheel feels better than a 1200g wheel with plenty of rotational inertia.

    the difference of weight between a traditional full carbon frame and a disc specific carbon frame is around 150-250g. my iPhone weights more than that. 5 sips of water from a bidon weight similar to that. with today’s disc brakes for road bikes: if you want to climb faster, train harder.

    and yes, i agree the UCI wants to make sure everything on discs will run as smoothly as actual technology, and by that i mean standards and real world usage. i think manufacturers should really decide standards that will be efficient and will apply to road cycling, for example the direct mounting of calipers so it won’t look like [and be] mountain biking technology adapted to road bikes, but genuine evolution of the quality of ride of road bikes, inspired from the fastest and most advanced vehicles on the planet [which by the way have disc brakes as standard]

    i personally think 15mm front thru-axle and 12mm back axle is a great way to improve rigidity and durability of a frame with/without disc brakes, and direct mount looks much much cleaner than post mount like in mountain bikes.

    the only thing i think dave is right about, is wider tires. and that generally is only if it’s on wider rims, otherwise there’s no real performance gain, structurally and aerodynamically speaking.

    people fearing change on their bikes and giving the industry evolution of performance, safety and speed are the same ones that feared the television would kill the radio.

    the best brakes are the ones that let you go faster.

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