Road bikes: to Disc brake or not to disc brake?

Mountain bikes and hybrids have been equipped with disc brakes for a long time – but it’s only over the last couple of years that they’ve made their way on to road bikes.

A rare role reversal

Disc brakes present a strange and rare opportunity to bike manufacturers – because they give everyday cyclists access to something the pros can’t have.

Usually, road bike technology appears first in the peloton, before dribbling down to high end bikes, then to mid range bikes, and so on. In this case, however, the UCI have banned the use of disc brakes (for now) so the pattern changes.

Disc brakes are banned in UCI sanctioned competition due to concerns over giving racing cyclists brakes that stop them abruptly, as this could cause crashes, especially if stopping power varied between bikes and riders. The UCI are also reportedly worried about the sharp rotors causing damage in the event of a crash.

Most of us don’t ride wheel to handlebar down hairpins at 40mph+, and we don’t intend to crash in a bunch, so these concerns are not to be worried over for Joe or Joanne Bloggs.

Why disc brakes?

The benefits of having disc brakes on your bike are:

  • Faster stopping – the pads bite the disc, the bike stops – it’s quick, ideal for commuters.
  • Not affected by wet weather – as winter gets closer, this becomes more important. Rim brakes are usually slower to react in the wet and this can be a bit annoying, or potentially dangerous.
  • No rim wear – rim brakes cause the bike to stop by clamping onto the rim. If grit or dirt gets caught between the two surfaces, this can result in wear, which happens over time regardless. This doesn’t happen at all with disc brakes.
  • Lighter rims – as a result of decreased wear on the rims, they can be lighter.

Negatives:

  • Disc brakes are a bit heavier. Not much of a concern if you’re already travelling with a change of clothes, shoes, and a laptop.
  • Maintenance is a little more complicated, as pads are a tad less accessible and do need replacing from time to time.

What’s out there?

Firstly, when opting for disc brakes you choose between mechanical discs and hydraulic discs. Mechanical disc brakes use a cable system, and are usually cheaper. Hydraulics are the higher end option – the benefit is that the entire system is sealed so no grit can get in, but they take more maintenance.

The disc brake road bikes on the market at the moment are primarily aimed at commuters, all weather riders who want to complete a sportive in any condition, tourers and to a degree those who want to take the odd excursion off road.

These come under various names. It’s worth remembering they are all very much on a sliding scale, and separated by tiny tweaks to geometry – a few mm here and there, and slightly different componentry, such as thicker of skinnier tyres. And of course, not all bikes advertised in the genre will come with disc brakes, but these are the areas where they are becoming popular:

Endurance Road – Generally these are road bikes that have been designed with relaxed geometry to suit all day riding. This is a perfect ‘winter bike’ if you’re the type to have seasonally named bikes, and also a great commuter – comfortable for everyday riding but still fast like a road bike.

The Specialized Roubaix is an example of an endurance road bike, and it’s available with rim and disc brakes.

specialized-roubaix-sl4-disc-2014-road-bike

It’s been designed with Paris – Roubaix in mind – the one with the cobbles… so you can expect something pretty tough..

121-260-PIC20043451-775

Cyclocross bikes – Designed initially for off-road races, CX bikes are more relaxed than a road bike, but still have a twitchy racey feel, though this will vary between brands and models as geometry will be tweaked. Not all CX bikes have been made with racing in mind, and phrases such as ‘perfect commuter’, plus inclusion of pannier rack mounts or mudguards mean it’s probably going to be less racey.

CX bikes are adapted to cater for mud – so they usually have more tyre clearance space, knobbly tyres, and a higher bottom bracket. The raciest of CX bikes still have rim brakes, due to the weight difference, but most now come with discs. These are great if you want a versatile bike, which will be good for commuting, road rides, and also off road riding, though for technical trails you might find a mountain bike an easier experience.

2013-cyclocross-world-cup-valkenburg-195-lars-van-der-haar

Adventure Road/Gravel Road – Sitting neatly between these two styles, is adventure road. Most of these have disc brakes, and they are made for riding rough paths – eg gravel or woodland. The tyres are knobbly as the CX bike, but bottom bracket doesn’t need to be as high, and there is a lesser need for tyre clearance.

Examples include the Cannondale Synapse Adventure Road, and the Norco Search range.

norco-search-xr-2015-adventure-road-bike

Do you ride with discs, and would you opt for them if buying a new bike?

Join 10,221 fellow cyclists who are subscribed to the London Cyclist newsletter

Sign up for our free newsletter to get...

  • Advice on the best cycling gear
  • A Friday roundup of all the latest London cycling news
  • Exclusive content not available on the blog

Subscribe today, and get exclusive access forever! (It's free)

*No spam, ever!

As seen on The Guardian, BBC and The Independent.

22 Responses to Road bikes: to Disc brake or not to disc brake?

  1. Giles Roadnight 30/09/2014 at 8:46 am #

    I recently got a new bike and treated myself to hydro disc brakes and Di2. I was expecting both to be good but I thought that the Di2 would really be the best thing about the bike.

    I was wrong.

    Disc brakes are SO good.

    This bike is mostly used for commuting through London but I also use it for the odd weekend ride.
    For commuting I got really fed up of private hire cabs pulling out in front of me in the wet, putting the brakes on and getting nothing. Disc brakes always work and always work consistently rather than starting to work after a random period of nothing like rim brakes (and for me usually then locking the wheels as I was pulling the lever so hard).

    I rode this bike during this year’s Ride London 100 which was so wet it actually became the Ride London 86. Whilst everyone else was having to take it carefully hoping that they would be able to stop I had no such issues. The brakes worked perfectly the whole time despite the horrible conditions and cycling through a foot of water.

    HIGHLY recommended

    • Elaine 25/11/2014 at 1:29 pm #

      Out of interest which bike did you get? I am hovering over the Rose Xeon CDX at the moment. Its down to the Canyon Endurance (without disc brakes) or the Cube Agree or Rose Xeon with discs.. just don’t know whether to take the disc plunge!

  2. MJ Ray 30/09/2014 at 9:39 am #

    If you’re not worried about weight too much and want brakes that are out of the rain and don’t wear rims, why not go for hub brakes?

    • Vincent 30/09/2014 at 10:27 am #

      Aren’t hub brakes limited to the rear wheel?

      When stopping, most of the braking must be applied to the front wheel.

      • Alan Moore 30/09/2014 at 2:40 pm #

        No. My front hub is a brake and a dynamo. My rear hub is a brake and 7 gears.

    • Alan Moore 30/09/2014 at 2:39 pm #

      I use hub brakes on my daily rider now, but had hydraulic disc brakes on my previous bike, a hybrid.

      Discs are not entirely without lag in the wet, although it’s much less than with rim brakes which have a huge surface area to dry off before they get to work. Discs are awesomely powerful though – a side effect of which is the lack of effort required: they only fitted a tiny two-finger brake lever and that was always plenty.

      Hub brakes are not as powerful as disc brakes, but being enclosed they do work immediately whatever the weather – and require practically no maintenance. Ever.

  3. Rob Fletcher 30/09/2014 at 10:10 am #

    I bought a CX bike with mechanical discs a couple of years ago when the first affordable models started to appear. The brakes it came with (Avid BB5) were horrible – constantly needing adjustment & unreliable. I upgraded to BB7s and the difference is phenomenal. I hardly touch the things now. New pads every now & then and a very infrequent tune up (which is also much easier to do than with BB5 or rim brakes).

    I went for discs with all-weather commuting in mind & they’ve proved their worth.

    I’d be interested in looking at hydraulic options. When I was last looking they weren’t affordable for drop bars. When riding mountain bikes I’ve found hydraulic brakes a bit “binary” though. Great if you want to crash stop. Less so if you want fine control like feathering off some speed down a hill.

  4. Mik 30/09/2014 at 11:10 am #

    I’ve been riding discs the last couple of years, hydraulics on my Sirrus and mechanical on a 2014 Synapse (also ridden through the Ride London 86 with no issues at all).

    I’d query the pros and cons, specifically I’m not sure a disc brake will stop faster than a rim brake, both can lock the wheel, that’s as much braking as you can deliver. In the wet, discs win every time but in general not so different if your rim brake is set up. What you do get with discs is much more modulation/feel (or you get it a lot easier). The pressure needed to lock a disk is greater than that to lock a rim, so you get access to a much larger spread of options for partial braking. Commuting it’s this that really shows for me, I want to scrub a little speed off, or I’m wary of what that car is doing. I know I can trust my discs to give me that feed back.

    On the Con side, I’ve spent considerably more time trying to get rim brakes set up right (and keeping them there) compared to discs which have tended to be set up and pretty much forget. But there is a bit of a question mark over hydraulic discs and overheating. Not an issue for most commutes, but if you start hitting the mountain passes with hydraulics it’s worth changing your braking style. With rim brakes there is a habit to trail the brakes, with discs this could lead to boiling the fluid, it’s far better to brake deliberately when required. This different style is possibly the best of the UCI’s arguments, although I’d expect to see discs in the peloton sooner rather than later.

    I’ll ride rims, but I’d never swap my discs for them given the choice 🙂

    • vince 02/10/2014 at 11:53 pm #

      I commute around a city with varied terrain (not all roads) on a CX with cable discs these days. My brakes on that bike are Shimano BR-R517’s, and they work really well. If you choose, you can set them to lock the wheel in classic Shimano style (exactly what people used to complain about on their MTB brakes) or you can set them up to modulate before locking.

      The actual limit of braking is in the formula of tyre compound, contact patch area and coeeficent of friction available on surface. In practice, a 517 and 160mm rotor can easily generate more stopping power than my 28mm Conti Grand Prix’s can put down on a made surface. With something a bit knobblier and a loose surface they’re fine – the same CX bike sees a lot more miles than I thought it would properly off road (woods and mountains) and has led to me considering why I have hardtail MTBs at times.

      I ran rim brakes on a commuter for ages and have no desire ever to do so again. Anally keeping the rim clean helps a lot and is probably the source of most people’s woes but the faff and hassle compared to (good) discs is ridiculous.

      Regards adjustment of caliper, I usually only need to tweak every couple of months. I’m actually beginning to get worried that I have an 18 month old pad set in that’s outlasted three sets of tyres.

      I run hydraulic on mtb’s (Avid for preference although I also own Hopes) and don’t find much more hassle here really, although judging by the stuff online unless I have the only four sets of Elixir brakes that are easy to bleed and don’t need it doing every time you touch them there are a lot of people writing about Avid brakes who shouldn’t be allowed near a spanner.

  5. Barry 30/09/2014 at 11:59 am #

    About to get my Merida Cyclocross 700 within 2 weeks or so, with discs… First experience with them so very anxious to try them out. Heard some really good things about them!

  6. Adam 01/10/2014 at 12:17 am #

    Where does this concept that hydros need more maintenance than cables come from? The SLX discs on my mountain bike require literally no maintenance whatsoever, whereas any cable brake will require lubrication and cable replacement periodically.

    Changing pads is easier too, no toeing-in brake blocks or adjusting for wear – just lever the pistons back into the caliper (with the old pads still in!!!) and pop the new replacements in. Easy as pie.

    I’m running cable discs ATM but will swap to hydros when the new 105 stuff comes out.

    • noel 01/10/2014 at 7:53 pm #

      Fully agree, Adam!

    • Phil 02/10/2014 at 10:27 am #

      That is a handy tip about leaving the old pads in when levering the pistons back, no danger of knacking the piston seals. I will never go back to cable disc or rim brakes. The only maintenance hydraulics need is changing the pads, and a bleed if air gets into the lines. I always hated adjusting cables and screwing the pads in on non-hydros- don’t get me started on rim brakes!

  7. Dave 01/10/2014 at 12:34 pm #

    After having disc brakes on my last 2 bikes (Giant Roam and Boardman CX) I would never go back to rim brakes. Performance of the discs in the wet is light years ahead of any rim brake (IMHO). Couple that with the fact that modulating the braking force is easier with disc brakes (I just think you get better feedback feel from them).

    Hopefully it won’t be long before hydraulic brake systems become available for drop handle bar bikes at similar prices of those for flat bar systems.

  8. AH 01/10/2014 at 1:46 pm #

    I have Avid BB7s on my bike and I find setting them up is far easier than rim brakes. Basically just dial them in (a torx on one side, hand adjustable on the other) until they just touch and back them off a click.

    Braking performance is far better in the wet and you don’t have to clean all the black crud off your rims.

  9. Kennym 01/10/2014 at 4:14 pm #

    I have hydraulic disc brakes on my commuter bike and have twice been rear-ended by guys on bikes with rim brakes when I’ve been forced to brake sharply (one by a car pulling out on me, the other a cyclist). It’s a long time since I’ve ridden a bike with rim brakes, I doubt I’d go back to them now.

  10. Gaz 01/10/2014 at 9:03 pm #

    From an mtb perspective, Hydraulic disc brakes require almost zero maintenance. Pads are simple to change, almost fit and forget. Brake bleeding is not difficult if they need it. Shimano hydraulic systems are much much better than avid which you need to avoid.

  11. Tom 02/10/2014 at 1:03 pm #

    Another vote for Avid BB7’s here, so good and so easy to set up and adjust (not that they seem to need much adjusting) I fitted them to my bike Marin Lombard to replace the terrible Tektro discs that came with it and the difference is astonishing.
    I can’t see me ever wanting the additional fuss of hydraulic brakes if these are available.

  12. Spencer 02/10/2014 at 10:12 pm #

    I have two bikes, one with Ultegra rim brakes, one with Hope X2 hydraulics (with 180mm rotors). The differences in stopping are like night and day!

    The Ultegras I have to try and guess when to stop and if someone steps off the pavement or a car cuts me up I have to try and anticipate in order to stop without a collision.

    The Hopes don’t generally have to worry about that, just pull the leavers and depending how hard I pull reflects how quickly I stop. In fact only issue being in the wet or going too fast I can skid quite easily if I pull too hard which being clipped in can be a bit hairy!

    With regards maintenance once fitted the Hopes have been maintenance free. I had to bleed them after shortening their length but your average bike user won’t have to worry about stuff like that.

    Go hydraulic disc brakes, you won’t regret it!

  13. William 04/10/2014 at 9:59 pm #

    I’m just convinced by the commuters who claim they need to stop quicker because drivers pull out. It happens of course but better observation and less speed helps way more than more powerful brakes. Disc brakes on MTBs are essential if you are serious due to the nature of the ride.

    • Giles Roadnight 05/10/2014 at 11:22 am #

      Sorry but that’s a load of rubbish. I’ve had situations several times whilst riding home from work where I have seen a car waiting to come out of a side road so I have back off to make sure they’ve seen me, they looked directly at me to check it’s clear, then have pulled out right in front of me anyway. As there were no cars coming they’ve assumed it was clear.
      In this example I was VERY well illuminated and the driver looked right at me and pulled out anyway. You’ll see in the description I complain about my brakes not working. It’s situations like this that I am thankful I now have discs.

  14. Jake 27/11/2014 at 12:11 am #

    I ride a Saracen Urban Hack 1 which is a cyclocross bike which came with rather slick tyres. I don’t actually ride Cyclocross, I chose the bike because I wanted a road style bike which could take a bit more punishment, and i think I’ve made te right choice. Disc brakes haven’t failed me yet, and the tyres/inners have put up with roads, pavements, curbs, gravel paths and all that which my commutes come across.

    Also, one of the great things about cyclocross bikes is that they’re designed to fit comfortbaly on your shoulder to carry them, which is fantastic for me as my work is situated on the other side of a railway track and the fastest way across it is by going up and over the footbridge which has stairs.

Leave a Reply