Disc brakes: The future for all bikes

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By James Huang and Matt Pacocha, in Boulder, CO | Saturday, Dec 24, 2011 8.00am

In June 2010, the UCI announced they would allow disc brakes for cyclo-cross and techno geeks rejoiced. They knew the rule reversal was the first step to seeing the technology trickle to the road, and trickle it will.

We have good information that Shimano’s future update to Dura-Ace will offer a mechanical disc option, and there are believable rumors that SRAM are working on a hydraulic disc system for Red. And of course there are viable stopgaps available now, TRP’s Parabox being the best, followed by a host of mid-grade mechanical options from Avid, Hayes and Shimano.

We’ve put a full season on multiple disc brake equipped cyclo-cross bikes and we’ve come away sold on the concept, and much of the technology currently available.

Putting discs to the test during the 2011 boulder cup, a uci c1 event—if we had only won, we would have beat tim johnson to the punch:

Putting discs to the test during the 2011 Boulder Cup, a UCI C1 event – if we'd only won, we'd have beat Tim Johnson to the punch

On the last weekend of our local cyclo-cross season we were presented with a gift: two true mud races. At these events we ran discs alongside both high-performance cantilever and linear-pull brakes. The discs came out on top, offering more control than either of the other two options, not to mention the fact they kept our bike cleaner, longer.

Even wheel changes can be quicker and easier with discs, if you do a little work up front. Syntace offer shims that allow you to set the rotor spacing on all of your wheels to exactly the same position. So if you have to change a wheel in the pit, there are no cables to undo, no arms to open up and no rim dimension variations to account for.

Mud tire testing at ’Cross of the North (credit: Brian Patrick, OnSight Media)

These last two races were the icing on the cake for our season on discs. In our opinion, there are only a few small issues holding mass acceptance back: weight and the current lack of a full-hydraulic option. And those downsides aren't deal breakers by any means.

Tim Johnson's (Cannondale-Cyclocrossworld.com) Cannondale SuperX still weighs just 16.42lb with Avid BB7s front and rear, and one of BikeRadar's writers is riding a 2012 Dedacciai Super Cross that weighs 7.7kg (17.0lb) with a relatively conservative, but still elite-level, build that includes SRAM Force, Avid BB7s, Stan's NoTubes ZTR Race Gold alloy tubeless clinchers, Shimano XTR pedals and all-alloy cockpit components.

Even smaller companies like dedacciai are placing themselves on the cutting edge with disc-only carbon 'cross framesets like the super cross: even smaller companies like dedacciai are placing themselves on the cutting edge with disc-only carbon 'cross framesets like the super cross

Even smaller companies like Dedacciai are placing themselves on the cutting edge with disc-only carbon 'cross framesets like the Super Cross

It’s not just about better braking…

We're not the only ones who can see the advantages of disc brakes for drop-bar bikes. Last week, VeloNews tech writer Caley Fretz penned a piece on discs for road in which he highlighted the potential safety benefits they would provide. Fretz’s argument is based upon that fact carbon fiber is far from an ideal braking surface.

In mountainous terrain, carbon clinchers battle tire pressure changes, and the wringer their sidewalls are put through, by the heat that builds under the friction of braking. Carbon tubulars, while safer, still present issues, even when they’re ideally set up. Just about all of the issues surrounding carbon wheels are rooted in the task of braking and thermodynamics, so when you remove the braking duties from the rim, things get a whole lot better, and safer.

Zipp's prototype 303 firecrest tubular wheelset, set for cyclo-cross: zipp's prototype 303 firecrest tubular wheelset, set for cyclo-cross

Discs offer safer braking with carbon wheels

So for that reason alone, discs have clear benefits for road bikes, and still there are a host of other advantages:

  • Better modulation, which is more important in braking performance than power (of course, there's the possibility of more power too)
  • The ability to build new rim shapes that are more aero, more compliant or stronger, due to the fact that they don’t have to accommodate a brake track
  • Faster wheel changes, especially between wheels equipped with different rim shapes
  • Possibility of less rotational weight, due to the reduced material needs of a brake-track-free rim
  • The ability to further tune chassis components (seatstays, fork) for ride characteristics, rather than reinforce them to accommodate brakes
  • The consistency, durability and adverse condition performance of hydraulics versus mechanical systems
  • Ending premature wear to rims and wheels by moving braking wear to a rotor
  • No need for ultra expensive carbon-rim-specific brake pads
  • And, for advanced users, a new ability to drive their bikes with their brakes

It’s a list that can continually be added to as a rider becomes more and more familiar with riding discs on the road or for ’cross.

Pioneers, take advantage

The momentum is building behind those test mules (both products and riders) for the concept of discs for ’cross and road. Manufacturers are readily building prototypes; we sourced high-end carbon disc wheelsets from both Easton and Zipp.

And one progressive pro has taken to riding them for more than just photo opportunities: Tim Johnson became the first pro cyclo-crosser to win a UCI C1 event with disc brakes at Jingle ’Cross in November, and raced round five of the 2012 World Cup in Namur, Belgium on discs.

Tim johnson won a uci c1 event this season on his cannondale superx disc prototype:

Tim Johnson won a UCI C1 event this season on his Cannondale SuperX disc prototype

He’s the first rider to help prove the brakes, and he’s turning heads. “We decided that we wanted to try it, because I felt like, at certain events, it would make a pretty big difference,” Stu Thorne, Cannondale-cyclocrossworld.com team owner, told BikeRadar. “In LA, Tim won on Saturday and [Ben] Berden came up to me Sunday morning and he wanted to ride the bike around in the parking lot.

"So he was riding TJ’s bike around there, and came back and said, in typical Belgian [fashion], ‘whoaf, this is awesome’. He said that every corner where there was heavy braking, Tim would open up a gap on him, and it made him work just that little bit more.”

Volagi's liscio disc road bike: volagi's liscio disc road bike

Volagi's Liscio disc road bike

Past that, progressive road brands, like Volagi are putting disc road bikes out, now. Finally, chew on this: every other high-performance wheeled vehicle uses disc brakes, from car, to motorcycle, to racing lawnmower, to mountain bike. Is it time for ’cross and road bikes to step up? We think it is.

Once component manufacturers start to offer integrated hydraulic setups and frame companies start optimizing designs for discs, we'll be left asking why it took so long. It's only due to legacy that we've all come to accept that squishing a couple of little rubber blocks against a carbon or aluminum rim is something other than ludicrous.

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User Comments

There are 29 comments on this post

Showing 1 - 29 of 29 comments

  • Garlic bread..... now that's the future

  • Finally the road world awakes !

  • ' It's only due to legacy that we've all come to accept that squishing a couple of little rubber blocks against a carbon or aluminum rim is something other than ludicrous.' I remember saying almost those exact words in a thread I started on Bike Radar years ago, and got shot down in flames. Cycling is a very conservative community...

  • Disc brakes do bring some non-insignificant advantages, in certain circumstances, and not just in terms of convenience or bragging rights, so I am not totally opposed to them, unlike electronic shifting. But I am not looking forward to the pile-ups when newbies start turning up at races with disc-equipped bikes, and slam on their brakes in the middle of a tight bunch at the first sign of trouble.

  • After the Midlands championships at Sundorne earlier this month I asked Hope team rider Dave Collins, who took 3rd place, about his disc brakes. Interestingly, he said that riding carbon rims that he felt disc brakes provided greater benefit in the dry, with predictable braking every time, regardless of the state of the rim.

    As someone who is mechanically sympathetic but not in a position to buy wheels too often, the prospect of wearing out a set of disc pads infinitely preferable to scoring grooves in some post rims over a season or even just on training rides. For me it can't come soon enough.

  • After a winter series with a v-brake at the front and an Avid 5 at the rear I never once wished I had disc brakes. I always had enough brake power and modulation in the dry and wet.

    I'm always interested to see magazines pushing new technology, mainly because innovation sells bikes and magazines, and innovation relies on magazines spreading the word and advertisers paying them to do so.

  • now if only we could get those CX riders to ride a real bike and get riding some XC we'd be onto a winner!

  • "But I am not looking forward to the pile-ups when newbies start turning up at races with disc-equipped bikes, and slam on their brakes in the middle of a tight bunch at the first sign of trouble."

    Interestingly there is a parallel here with disc brakes in cars. One Indian company started to fit them (to Hindustan Ambassadors?). The new cars were always getting rear ended until the manufacturer fitted a warning badge to the effect that the car in front had disc brakes!

  • Get used to soon to be seen 29ers racing in CX

  • "And, for advanced users, a new ability to drive their bikes with their brakes"

    Can someone explain this to me/

  • "Syntace offer shims that allow you to set the rotor spacing on all of your wheels to exactly the same position."

    Could I get a link to this?

  • I've had a disc-equipped CX bike for 6 years - I had the frame custom-built because nothing was commercially available - it's great for hacking around the woods, singletracking and general trail riding. However I'm sticking to rim brakes for my CX race bikes because grip and the ability to get round bends and up hills makes far more difference - I can lock my brakes (TRP CR950s) easily

  • Monty Dog,

    That's exactly the point. The true measure of brake control isn't how easily you can lock things up but how closely and repeatably you can stay just shy of that point for maximum braking power.

    WV Cycling,

    Here you go: http://syntace.com/index.cfm?pid=3&pk=757

    micah356,

    Better brakes allow riders (and drivers, for that matter) to use them more liberally as another method of control. Riders with better brakes will be able to come into corners faster and with more confidence because the deceleration will be more consistent and predictable in a wider variety of conditions.

  • Disc are sure the way forward, as mentioned all other forms of wheeled performance racing have adopted disc's- since I believe Jaguar first raced on them.

    My concern on a road bike would be that weight will be a driving factor and that will limit both caliper,rota and reservoir size. This miniaturised system will therefore have a reduced amount of fluid. This all leads to a catastrophic build up of heat. Perhaps the average ride along the local rolling hills wont be trouble but an alpine decent slowing from 60-70kph time and time again will have implications. You then have to look at compounds do you have a sintered high temp compound that has little low temp performance or an organic type with better low temp but high wear and fade characteristics. There is a lot of work to do.

    Bring on the future - like electronic shifting embrace tech, its not always just marketing.

  • Quote: "The ability to further tune chassis components (seatstays, fork) for ride characteristics, rather than reinforce them to accommodate brakes"

    Doesn't make sense. A disk caliper is mounted much closer to the axle (say 75mm vs 300 for conventional brakes) so , since torque =f x d , the force on the frame/fork will be at least 4 times GREATER for disc brakes. Whats more, a conventional front brake is mounted next to the strongest part of the fork . Forks will have to be stronger and heavier to take these forces.

    Front wheels will also have to be cross to take the torque (take a look at the Volagi's Liscio) which will be a huge fashion change considering how almost every road front wheel currently made is radially spoked for aerodynamics.

  • Discs can not come soon enough! One of the major advantages I noticed moving from V brakes to discs on my XC machine ,was that the sludge that formed from the brake block material being worn away was no longer an issue. Made for a much cleaner bike, which is important because it is stored inside.

    I will only purchase a road machine when it comes with discs.

  • I can't agree with most of the comments here regarding discs on road bikes and feel that being on the road is about keeping moving - Not Stopping.

    Tom

  • I'm completely with Monty on this - CX races are won by the fittest rider, usually with good bike handling skills, not by the one with the best brakes.

    Angryasian - I know you're a techie, but I think the pure technology of this topic is distracting you a bit here. I'm sure discs are better than rim brakes for all the reasons you say, but let's not get carried away the belief that discs will give you any kind of performance advantage in a real world CX race - or even a road race for that matter.

  • All these comments mirror exactly where we were 15 years ago with the introduction of disc brakes on mountain bikes. Just try buying a new MTB over £300 with rim brakes now and you will see where we will be in a few years time, it's comming so we may as well embrace it ! And before anyone else posts about "stopping" being unimportant for roadies, road bikes are one of the only forms of vehicle, sporting or otherwise which still employs such an archaic method of slowing down. Every other form of vehicular sport realises that consistancy in stopping is a performance advantage to becoming quicker. Life is all about progression, after all if someone hadn't of invented the toilet we would still be pooping in a hole in the ground !.......time for Xmas dinner !!

  • The real development isn't CX brakes, it's road bikes. CX is niche/weenie but road bikes are the real area. I've already converted my commuter to discs - what a relief! No way am I going back to rim brakes. Now I just need to convert my good roadie, once the tech catches up.

  • To the author, how hot did the brake disks get during your races? My MTB disks get very hot; hot enough to brand their shape onto your leg.

    Do you see a risk with a hot disk when shouldering a bike up a climb?

  • @chaingangcycles - the point I'm making (and the point you're missing) is that, despite the prevalence of discs in MTB, it would still be possible to win a cross country race on rim brakes today.....so much for technology...

  • maybe but it would depend on how easy the course/conditions were. But the point is simple - anyone who thinks rim brakes are as good as discs is never going to persuade anyone these days.

  • it wouldn't depend that much on conditions as you can use different compounds to increase braking in bad conditions .

  • Anyone who saw Cancellara belting the crap out of the descent in the 2009 TdF knows that the weight penalty is not worth it for discs. Sorry I would rather be able to ride my bike up a big hill quickly than have the ability to stop from 60km/h for the few times that happens.

    Just because it is claimed to be an advance does not mean it is.

  • The introduction of disc brakes will be fantastic for road bikes. Through product development, there will be a choice of light weight brakes with fantastic modulation and feel. For the weight obsessed there will be titanium and ceramic versions making the weight argument a non issue. The only thing to do is to make a conscious choice of what you want. Will make for some very interesting bike designs and avoid wearing out the rims on those expensive carbon wheelsets !! Roll on the future (and garlic bread)...

  • Road cycling is about going fast and NOT stopping.

    The idea that we need disc brakes is ridiculous. I hardly ever touch my brakes even on fast alpine descents. I have never, ever wanted more grip and brake modulation has always been excellent. Hasn't any of these disc fanciers noticed that road cyclists have been moving towards simpler road bikes like fixies NOT, ever more complicated technologies like discs.

    I have never, ever heard a true road cyclist wanting discs, It seems to me only, off -roaders are obsessed with them and the technology.

    When I start seeing discs regularly in the pro-peleton and the bikes still coming in at under 7 Kg I will know that in 10 years they might hit the real cyclist and be ready. Until then my Campag Records and Zero Gravity brakes will just have to do. As for not wearing Carbon Rims out on the Road - I have had mine for years and they look like new - They are for going fast - If you are sitting on your brakes on these wheels I suggest you may be doing something wrong.

    Tom

  • my specialized tricross sport needed discs. in the dry, you touch the front brake and it would slam to standstill in a split second and in the wet it would vibrate down the road at the same speed you were doing. it caused me to have several crashes, and even when the brake bridge was put on, there was little difference. although 'tradition' is important, so is progress. discs are a superior braking in all aspects to calipers and when roadies can stop being belligerent fuddy-duddies and realize that discs are better then the whole industry can get on and make some fantastic road brakes and wheels

  • The weight of disc brakes is simply not an issue, manufacturers are adding weight to bikes to make them UCI legal, a few grams extra in the brakes will not affect the overall weight.

    The fact that proper disc brakes are overpowered for the grip available in road tyres is an issue but one that is easily surmountable.

    The big problem will be heat dispersal, on a long alpine descent current disc brakes that you find on mountain bikes will overheat and you will get brake fade so badly that they will stop working entirely. This is simply not an issue with most mountain and cross bikes as they travel much slower and the braking is more short and intense. to make disc brakes safe for use on the road manufacturers will have to completely redesign them.

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