The Future Is Here

The Future Is Here

I’m currently riding a carbon fiber road bike equipped with a mechanical drivetrain and hydraulic disc brakes. It wasn’t that many years ago that I wrote how I didn’t see how or even why disc brakes would make their way onto production road bikes, or even custom road bikes for that matter.

My concerns were voluminous. From a piece I wrote in 2013 I outlined the following problems:

  • If you boil your brake fluid on a descent, your brakes can fail.
  • Generally, you want the bike to offer some vertical flex at the dropouts; disc brakes would demand beefing up the fork and stays.
  • Many mountain bike disc brake system offer poor modulation. Road bike brakes need to offer great modulation.
  • Pad retraction is an issue on many mountain bike brake systems. Roadies won’t put up with rubbing brakes.
  • Disc brakes won’t improve a bike’s aerodynamics.
  • The hydraulic lines will require working hand-in-glove with manufacturers to offer suitable frames.
  • There isn’t enough room in control levers to add a master cylinder.
  • It’ll make the bike heavier. Roadies are allergic to heavier.

Each of those was an understandable concern. However, when I spoke to Brent Graves, who was then the product manager for Specialized’s road bike line at the time, he dismissed every concern I brought forward as just “an engineering problem.” His was the sort of confidence that allowed man to go to the moon. Every time I listed an issue, he’d repeat, “just an engineering issue.” In other words, ‘we will figure this out.’ NASA engineers decided how big the computer in the command module could be before they had the computer built for the rocket. It’s like saying, “I need a car, but it needs to seat six and get 100 mpg.”

I bumped into Graves this past week at Sea Otter. These days he is President and CEO of Cane Creek. Our conversation didn’t even bother with disc brakes. Why? Simple. That summer day back in 2012 he predicted that we’d be seeing the first production disc bikes by 2015 and by 2018 disc brakes would be available on bikes at a wide array of price points and groups. As it turns out, he’s better than the lady with the neon sign and the crystal ball.

All the proof we need is that you can find Tiagra hydraulic-disc-equipped road bikes at the $1000 price point. I’m not even sure Graves would have predicted that.

Now Graves had me at a disadvantage. In the summer of 2012, he already knew what was coming out in 2013. He had already planned what was to come out in 2014 and was working on the 2015 model year of bikes. It wasn’t impossible for him to extrapolate out from there, but still, a lot had to happen in three years, and on schedule.

I can’t say I didn’t believe him, but I knew I was going to need to see it to believe it. And now I’ve seen it.

But just what have I seen? First, I’ve never experienced hydraulic fluid boiling on a descent and brakes fading. The bikes I have ridden and reviewed don’t feel unusually stiff; they still feel like normal road bikes. I seriously doubted that ride quality would remain consistent. Modulation is off the charts, better than regular rim brakes. Some aerodynamic tests say that a bike’s aerodynamics decrease with the addition of disc brakes, but others say that disc brakes improve them; let’s call it a wash. As it turns out, manufacturers have been only too happy to route hydraulic lines internally. It makes assembling bikes hell, but it really cleans up the appearance of the bike. And my problem with no space for the master cylinder? Well, levers have gotten bigger, but not so much bigger that they are difficult to hold. SRAM even redesigned the shape of their first lever to make it more ergonomic.

The only points on which my concerns remain at issue are rotor rub and weight. Centering the rotor in the brake caliper isn’t hard to do with good lighting, but tolerances are so tight, the caliper needs to be moved each time a wheel is changed. Not dynamite, especially for pro racing. But what about weight?

So far every rider I’ve met who has ridden disc brakes has liked them. Also true is that every rider I’ve spoken to who has ridden disc brakes is willing to give up a pound or so to get such a staggering improvement in brake performance.

There’s another point I hadn’t considered when I was naysaying discs. I was concerned about the limits of adhesion of 700C x 23mm road tires pumped up to 100 psi. I mean, it is possible to skid a bike with those tires if you put a death grip on the levers. But what about when you’re running 28mm tires pumped up to 75 psi? I can say from personal experience that it’s a lot harder to break those tires free. Increase that contact patch to 40mm wide and you can brake hard—even on dirt.

Back to that bike I’ve been riding. When I enter a turn I brake significantly later than I used to and I don’t fear breaking the tires free and skidding (and losing control). The improvement in modulation gives me control I couldn’t imagine with rim brakes. The weight? I’ll take control over a lighter bike any day.

I own three bikes with rim brakes and I don’t plan to sell any of them any time soon (well, maybe one of them). They are great bikes all the way around. But disc brakes are absolutely better and certainly here to stay. Direct-mount brakes are arguably the dying gasp of rim calipers, though they are a pretty good gasp.

I’m not going to suggest that anyone who is pleased with their bike (or bikes) needs to buy a new bike. I am, however, impressed with Brent Graves’ vision. He was a proxy for a great many product managers and engineers in the bike industry. They believed that disc brakes would make for a notable improvement in road bike performance and they’d be able to offer it at price points attractive to almost any rider. They were right.


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  1. Les.B.

    Are there still disc brakes around with cable operation?
    How much does cable vs pneumatic affect operation?
    If pneumatic operation makes disc brakes work better, why is that not offered with rim brakes?

    1. Author

      Yes, there are cable-operated discs out there. They are very different from the hydraulic (not pneumatic) disc brakes. The feel is lighter, the modulation noticeably better and they require less service. Cable-operated discs solve some problems, but leave others unaddressed. Can you maybe do a slight rephrase on your last question? I’m not quite sure what you’re asking. Or, are you asking why rim brakes aren’t hydraulic? If that’s the case, I can say that it has been tried but it was really wonky. It was roughly on the rims, but the braking, based on my memory, was that it was not (surprise, surprise!) as good as even bad discs are today.

  2. Jeff

    SRAM has hydraulic rim brakes…. but why would you stick with rubber pads and what about rim material?

    A dedicated, free floating, brake surface with robust pads.

    My Cervélo c3 may not be aero as an S3 disc, but it eats chip seal roads.

  3. scott g.

    Disc brakes exist to make the world safe for carbon clinchers.
    Electronic shifting gives you room for hydraulics
    Wireless shifting reduces cabling time in bike builds.

    All the above are more complicated to service than their mechanical predecessors,
    driving more business to the LBS.

    Note for Les B. mechanical discs should only be used by people who love cantilever brakes.

    1. Pat O'Brien

      How are you comparing mechanical disc brakes to cantilevers? I use TRP Spyre and Spyke disc brakes and are very pleased with them in installation, adjustment, use, and pad changes. I have also used Avid mechanical disc brakes for years, and I found the TRP to be better in every respect, especially modulation, power, and noise. I replaced the Avid brakes with TRP on both my bikes, mountain and touring, that have disc brakes. Two pistons are simply better than one, and they eliminate the rubbing, noise, and problem adjustments that single piston mechanical disc brakes have.

    2. Author

      Ummmmm … I’m not even considering cantilevers. The industry has a host of reasons not to look at cantilevers for road bikes or gravel bikes. As to mechanical discs vs. hydraulic discs, hydraulic discs are an order of magnitude more powerful.

    3. Author

      Fair observations, those. I’m not sure I agree with every premise, but the upshot is the same.

    4. Dolan H

      Funny, the bike I service the least is my rain bike with hydro discs. In ~5000 miles I’ve replaced the pads once, which was dead easy. After that, they self adjusted, and worked great. No cable stretch to account for. I don’t have electronic shifting, but from my understanding, once you set it up it’s pretty much good to go outside the occasional battery recharge.

      So, if anything, these technologies seem to be making bikes need LESS service, even if the mechanisms are more complicated (hydraulics are actually pretty simple).

    1. Author

      Ha! No, but I will next time I talk to him. His job is different now, but I’m confident he still has his finger on the pulse.

    2. scott g.

      Pat, Cantilevers and Mech discs seem to require more fiddling and faffing about with to work.
      Also cantilevers should only be used by people liked geometry in school, Shimano
      does you no favour my including those pre built straddle cables.
      With hydros the only fiddly bit is when using q/r skewers instead of thraxles,
      alignment is more repeatable with thraxles.

  4. Winky

    Yep, I’m likely done with rim brakes from now on. No hurry, but my next summer/race bike is now more-likely-than-not to be disc braked (my winter/gravel bike already is). The aesthetic is even becoming appealing, with rim-braked bikes looking increasingly dated to my eye.

  5. Andrew

    I’ve been happy with the TRP cable actuated hydraulics. Cheaper than replacing my whole group. And I don’t think there is a good 10 spd hydraulic group out there. Let me know if there is!

    1. Jay

      Andrew – check out Gevenalle. They make a hydraulic brake/shifter system based on TRP Hylex hydraulic brakes. They add an indexed bar end shifter to the TRP brake lever. Models for 9, 10, 11 speeds, road or mtn, or a friction version that will shift anything. Sounds kinda wonky, bur they get great reviews from touring and gravel riders.

    1. Author

      This might be one of those Fifth Amendment thingies. Seriously, though, while my Deore XT cantilevers I used to replace my Mafacs on my old touring bike were reasonably powerful when considered against the calipers of the day, canti’s aren’t even as powerful as the current Dura-Ace direct-mount calipers, so the only upside to them is tire clearance, and even that is limited by the fork/rear triangle design.

  6. Brent

    It takes a big soul to go back and do a “mea culpa” piece on something you wrote five years ago that turned out to be wrong. Hard to do in the best of times, and increasingly rare these days. Bravo!

    1. Author

      That’s really kind of you. I’ll say that I think it was easy to do because the only possible damage was to my ego, and it’s taken much bigger hits than this. I just look at the upside: bikes keep getting better. I’m aware that a slice of RKP’s readership remains suspicious that evil multinational bike companies are trying to fleece them out of their hard-earned dollars, when they really are just bike geeks like us who are psyched they have a chance to do the best work they can. All those hardworking people (and there are increasingly women in roles of influence, though we could use more) deserve to be recognized for doing the best work they can.

  7. Dave

    And consider this–department store spitball bikes now have disc brakes. This is more important than disc brakes for any of us who read this forum. Why? Ever notice the people riding department store mountain bikes or hybrids with the rim brakes disconnected so that the wheels, which have never been tensioned or trued and are currently more crooked than the Trump and Bush families combined, will pass through the brake pads? Disc brakes separate brake function from wheel trueness–this could save somebody’s life who is riding a $199 Walmart special to work and back.

    1. Author

      It’s an interesting observation. Given that the root problem of all those department store bikes is that they are more poorly maintained than the Roman Empire, I am just wondering when it will be that I see a bike with its rotor removed because it got bent.

  8. Fuzz

    I’ve said it before, but your comments years ago convinced me to make that leap of faith and get discs on my latest road bike – a 2016 Roubaix. I figured I would like them, but I was not prepared to love them. As I tell folks, if you have a rim brake frame you really like, don’t feel like you have to run and out and replace it, but when you do get your next bike, buying rim brakes would be like buying a VCR.

  9. Lucien Walsh

    I hope so. Before kiddos I invested in a steel Seven; last year I had a little scratch, and agonized over whether to bring the Seven forward 34 years or buy a low-end disc bike (CAAD12 105). I went back and forth forever. In the end I just wasn’t sure I’d love disc brakes enough to turn away from my handmade, bespoke bike. So I put 6800 on the Seven (made no difference, except maybe now it’s easier to get parts than 2004 era Campy), and wheels (HED Belgium+ laced to DT240s). Wow did wheels wake up the bike, and it isn’t like the Mavic Elites were shite to begin with.

    Anyhoo, it will be ages before I can afford a disc bike on par with my current bike (nice bits, great wheels, panache). Maybe I would have loved a $1900 CAAD. Or maybe at 48 it’s time to freaking relax and enjoy the ride for what it is? Who knows. Maybe I can rationalize something in time for my 50th lol

  10. Sascha

    I agree in that disc brakes are a step up in performance (my mob has them) and yes they are the future but in my opinion they’re aesthetically unpleasing on road bikes…I would prefer to see the callipers and discs in a more compact design but I’m unsure if that will be possible in the future…

  11. Fuzz

    One reader was complimenting you for admitting to being wrong. I think that’s an incorrect characterization. You were merely being skeptical, which is a good thing in a reviewer. The proof was in the braking, as it should be.

  12. Chris

    I’m loving my Juin Tech (Yokozuna in the USA) mechanical/hydraulic brakes. Simple to install and I can use any brake lever I want. Not quite as good as the all hydraulic Hylex brakes on my previous bike but a huge improvement over the all mechanical TRP Spyres.

    The only part about discs I find more difficult to deal with is noise. When wet they can shriek like banshee if the pads aren’t kept clean. Here in wet Seattle I need to clean them every ride or two to keep them quiet. Organic pads have helped a bit but definitely more upkeep than with cantilevers. Still worth it given the massive increase in performance.

    1. Author

      The trouble with introducing disc brakes to the pro peloton is well-documented. I think it’s utterly irrelevant to how great disc brakes are. If we take what the pros are riding as an indication of what we should be on, given the number of Div. III teams on Ultegra and Force, no one should be buying Dura-Ace or Red. And that’s just ridonkulous.

    2. Geo

      Ok so pros don’t ride them and I’m in favor for disk brakes on off road, cross, gravel and road bikes given you go down long decents, etc…….
      What’s the logic with putting them on TT bikes? Ridonkulous right?

    3. Author

      I more or less (more) stopped caring about TT bikes. I just don’t really follow them. Some wind tunnel tests have shown an improvement in aerodynamics in cross winds thanks to the rotor, so I’m aware that an argument can be made. And I’m also aware that some people think chainstay-positioned direct-mount brakes don’t have great stopping power. I’ll leave this argument to others to sort out.

  13. Bob Mirabal

    A couple of riders in our small group got new bikes with thru-axles in the last two years with Dura-ace disc brakes. While the braking performance is impressive, they both have significant, embarassing noise problems and the bikes are constantly in the shop for new pads and rotor cleaning/replacement. What’s going on here? This is the only reason I’m not switching to discs yet, it seems that the technology, from my observations is not completely sorted out.

    1. Author

      I’ve got some noise issues with my 9150-series brakes on occasion, but this isn’t by any means a universal problem and if they are constantly replacing brake pads, that suggests a rider issue, not a brake issue; I’ve got more than 1000 miles on my first set of pads.

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