Disc Brake Pros and Cons

Disc Brake Pros and Cons

Disc brakes have become increasingly popular on bicycles in recent years, especially on all-road bikes with wide tires. Bicycle Quarterly has tested more than 20 bikes with disc brakes. Our challenging adventures have provided excellent opportunities to learn about the advantages and disadvantages of modern ‘road’ disc brakes.

I remember enjoying the excellent power and modulation of the then-new SRAM Red hydraulic discs on the descent from Naches Pass, but the caliper flexed the fork blade so much that the front wheel turned right each time I braked hard. At the other end of the spectrum, I sailed through a red light on a steep Seattle street, because an early mechanical ‘road’ disc simply lacked the power to stop the bike.

What you’ll read here is a more detailed and differentiated view than the usual “discs offer great stopping power” generalizations. As with many things, disc brakes have advantages and disadvantages. Whether they are right for you (and which ones to choose) depends on how you ride.

Experts like to point out that rim brakes are in fact disc brakes – the bicycle’s rim acts as the disc rotor (above). That is true in a technical sense, but it also points out the main differences between the two types of brakes.

On rim brakes:

  • Good: The ‘rotor’ – the rim – is very large (close to 600 mm on most road bikes). With such a long lever arm, the brake caliper does not need to squeeze the rim extremely hard to stop the bike.
  • Bad: The brake caliper must reach around the tire. This means that brakes for wider tires are heavier and more flexible than those for narrow tires.

On a disc brake, the opposite is the case:

  • Bad: A disc brake’s separate rotor is much smaller (140 – 200 mm on most bikes). The caliper must squeeze the rotor very, very hard to slow the bike.
  • Good: A disc brake caliper only has to reach around a very thin rotor. Thanks to the caliper’s small size, flex is not an issue.

The advantages of disc brakes are most pronounced on bikes with wide tires. That is why disc brakes are so popular for all-road bikes: Most rim brakes for wide tires offer sub-par performance. Here is why:

Scaling up the dual-pivot brake of a racing bike may provide clearance for 35 mm tires, but it results in a heavy and flexible brake. See the long lower arm of the brake in the photo above? When you brake hard, it will flex significantly.
Such a brake may feel fine during moderate braking, but pulling harder on the brake lever only flexes the brake, without increasing brake power on the rim. That is a problem during emergency stops. It’s an even bigger issue during wet rides, when you need extra braking power to squeeze the water off the rim. Anybody who has descended a mountain pass in the rain and squeezed the brake lever as hard as they could without being able to stop is going to look for a better solution.
The problems of rim brakes can be solved by moving the pivots closer to the rim. This reduces the flex, since only the part between the pivot and the brake pad flexes significantly. (It’s the part that gets twisted as the brake pads are pulled along with the rim.)
Cantilever brakes (above) locate the pivot close to the rim. That makes them very stiff. The problem is that the stiff brake is attached to the flexible fork blades or seatstays, which twist when you brake very hard. This changes the toe-in of the brake pads and results in poor modulation.
Centerpull brakes (above) have pivots near the fork crown or brake bridge, so flex is less of an issue. That is why they generally offer better modulation than cantilevers. The best models also have very stiff arms, and almost no brake lever travel is wasted to brake flex.
Placing the pivots next to the rims is such a logical solution that it’s now used on racing bikes, too: the latest “Direct Mount” brakes use the same geometry. The only difference: The arms are actuated by a linkage (which adds weighs and friction, but eliminates the need for a straddle cable).
Really good rim brakes for wide tires exist, but they aren’t very common. This may be one reason why disc brakes have taken over. They are better than “average” rim brakes.
How do disc brakes compare to rim brakes?
The advantages of disc brakes are easy to understand:

  • Power independent of tire size: Brake design (and power) are not constrained by tire size. You can use the same brake for any tire, and you get as much brake power with wide tires as you do with narrow ones.
  • Wet-weather performance: Because the rotor is small, the caliper must squeeze the rotor much harder than it does on a rim brake. This means that water will be scraped off the rotor quickly when riding in the rain. The best rim brakes also have enough power to offer decent wet-weather performance, but with disc brakes, even relatively inexpensive models work fine in the rain.
  • Separating tire and brake eliminates the risk of cutting into the tire with maladjusted brake pads. There is no risk of overheating the tire during long mountain descents. It also keeps rim and tire cleaner.
  • Switch wheels sizes on the same bike. For example, I could ride my Firefly (photo at the top) with superwide 26″ tires on rough gravel, with moderately wide 650B wheels on rough roads, and with skinny 700C tires on super-smooth roads. The outer diameter of all three wheelsets would be the same, and where the rim is located doesn’t matter with disc brakes. (In practice, this isn’t really an advantage, since the latest research by Bicycle Quarterly shows that wide tires roll as fast as narrow ones even on smooth roads.)

As so often, the same features that are responsible for the advantages of disc brakes also can be disadvantages:

  • Mechanical disc brakes often are not very powerful, because their rotors are so small. With 160 mm rotors, mechanical disc brakes don’t stop you as well as good centerpull (or racing dual pivot) brakes. This problem can be solved with bigger rotors. Stay away from “road” bikes with tiny 140 mm rotors. They are simply too small for optimum braking on pavement.
  • Hydraulic disc brakes offer plenty of power, but their hydraulic lines tend to be fragile. On one test bike, we had a brake line blow out after it got kinked slightly during shipping. Fortunately, this didn’t happen on the road, but in the workshop while adjusting the brakes.
  • Grabby: The most powerful disc brakes can suddenly lock onto the rotor. Especially at low speeds, braking power is hard to modulate. This isn’t a huge deal, but it shows that disc brake technology is still evolving.
  • Pad rub: Disc brakes must be very close to the rotor – this is the flip side of the high mechanical advantage that scrapes off the water so effectively in the rain. If the rotor is slightly out of true, it will rub on the pads and make annoying squeaking sounds.


  • Pad wear: Disc brake pads are relatively thin, and they wear out much faster than rim brake pads. On long, wet rides, you can run out of brakes completely, so carry spare pads! Fortunately, pad replacement is easy on most models.
  • Weight: Many bikes with disc brakes are heavier than their rim brake counterparts, but this needn’t be the case. Yes, the extra rotor and heavy caliper add significant weight, but much of that weight can be saved again on the rim, which doesn’t need a brake track, nor extra material to accommodate wear. With high-end carbon rims, a disc brake bike will weigh almost the same as with a good rim brake setup. The down side is the high price of carbon rims.
  • Stiff fork blades: Disc brakes require relatively stiff fork blades, because the caliper is mounted near the bottom of the fork. This means that the small-diameter, shock-absorbing fork blades of our favorite custom bikes don’t work well with disc brakes. For production bikes, this isn’t really an issue. Most production forks don’t offer much shock absorption anyhow: They are plenty stiff for disc brakes.

In a single sentence, the conclusion may be as follows: Even mid-range disc brakes offer adequate performance. The best rim brakes also offer plenty of power, but cheaper models for wide tires do not offer good braking, especially in the rain.
For a custom Allroad bike, where I can choose the best brakes and design the bike around them, I still prefer rim brakes. The best centerpulls (with brazed-on pivots) offer a sweet modulation that discs cannot match. Rim brake pads last much longer. And they can be used with the flexible fork blades that increase comfort and speed, especially on rough roads. Just watch your pads to make sure they don’t cut into the tire. And be prepared to get muddy legs during long, rainy mountain descents (below).
But if you are looking for a production bike, centerpulls with brazed-on pivots aren’t really an option – no production bikes I know come equipped that way. Cantilevers offer fine stopping power, but especially with carbon forks, you often get brake judder. Disc brakes often are the best option for these bikes. Choose good brakes, maintain them well, and they won’t detract from the enjoyment of your bike. Here is what to look for in disc brakes:

  • For the ultimate in stopping power, get hydraulic calipers.
  • The best mechanical discs are fine for most riding. Make sure your front rotor is no smaller than 160 mm. I’d prefer 180 mm. (200 mm tends to be too grabby at low speeds.)
  • Check your pad wear regularly. On long rides, carry spare pads.
  • Be prepared for the occasional squealing as your pads rub.

Further reading:

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Comments (161)

  • Mike Stead

    Hi Jan, I think in the interest of ‘balance’ you are overplaying the disadvantage side here:
    “hydraulic lines tend to be fragile”: this was *shipping damage* that could have been *any* component. In 20yrs of riding MTB/Road I’ve *never* seen a hydro line fail.
    Grabby: only seen this on silly wavy rotors.
    Pad rub: Face mounts properly, then not an issue.
    Pad wear: Got 3000 muddy, salty, road km out of stock TRP HyRd pads. Much better than rim pads.
    Cheers, Mike

    January 10, 2017 at 5:02 am
    • Jan Heine, Editor, Bicycle Quarterly

      Pad rub: Face mounts properly, then not an issue.

      During last year’s Technical Trials in France, almost half the bikes with disc brakes were penalized for rubbing pads. Considering that these bikes were set up by their builders, it seems like the problem is hard to avoid.

      Pad wear: Got 3000 muddy, salty, road km out of stock TRP HyRd pads.

      It probably depends on where you live. The same pads lasted less than 1000 miles on my Firefly. After one long descent where the road was so rough that we had to keep our speed in check, the pads had worn so much that I had to stop and adjust the brake, because I could pull the levers to the bars. With Compass centerpull brakes, I get at least 8,000 miles out of a set of pads under the same conditions.

      January 10, 2017 at 6:23 am
      • John B.

        The main issue I have with rubbing brakes is a corner case, if you will. The clearances required (pad to rotor distance) for disc brakes are tight but, perhaps, tolerances are not tight enough. I say this because switching wheels – with identical hubs and rotors – can result in rubbing brakes. The workaround is to adjust the calipers to work with the “outermost” rotor and to use thin (0.2mm) shims to adjust the rotors on other wheels to match.

        January 10, 2017 at 7:57 am
        • Jan Heine, Editor, Bicycle Quarterly

          As you say, even with through axles, switching wheels usually results in rubbing of the pads. Sometimes, simply removing and installing the wheel results in pad rub, too. Adjusting the rotors on all your wheels is a good idea, if you swap wheels on the same bike.

          January 10, 2017 at 8:00 am
      • John B.

        Don’t forget that TRP Spyres have an annoying problem that I am surprised you haven’t commented on. The pad adjustment bolts do not have detents. When you adjust the pads for the first time, those bolts are very difficult to turn because you have to break the bond of the Loctite that the bolts come coated in. However, subsequent to that, the bolts turn freely and refuse to stay in adjustment. TRP’s Hy/Rd model is much prefereable, IMHO.

        January 12, 2017 at 1:50 pm
  • Steve Palincsar

    You do not mention as a disc brake advantage the characteristic I’ve found cited by enthusiasts as the single most important advantage of disc brakes: low lever effort. They usually call this “better stopping power,” and it isn’t until you ask follow-up questions about what “stopping power” means that this emerges.

    January 10, 2017 at 5:14 am
    • Jan Heine, Editor, Bicycle Quarterly

      I think that depends on the brakes. Hydraulic ones really do require only very low lever forces, to the point where on bumpy roads, it’s hard to modulate them, as all your body movements are translated into changes in brake force. Mechanical discs do require lower lever forces during light braking, but when you brake hard (as I tend to do), you still need to pull on the lever with considerable force, just like on a rim brake.

      January 10, 2017 at 6:25 am
      • Gugie

        I’ve ridden the “Velodirt” North Trask ride 3 times. The first was with MAFAC RAIDs, the second with cantilevers, and the third with TRP Hy/Rd brakes. There’s a fantastic “slalom” downhill from Forest Grove about halfway to Tillamook that requires both lots of braking force. The first 2 times my hands were tired from all of the braking I had to do, but with the discs it was no problem – my hands were ready for more.

        January 10, 2017 at 4:00 pm
  • ORiordan

    Great overall summary.
    What about cable operated brakes with hydraulic pistons, like TRP HyRd?
    One thing I’ve noticed with all weather commuting using a bike with disc brakes in a city, is eventually I always seem to get brake pad contamination, I assume from things like oil and other assorted pollutants in puddles.
    When this happens, the brakes squeal like a banshee which may serve as an audible warning of my presence, but is also very annoying.
    There is only so much cleaning can do and the only answer is to replace the pads.

    January 10, 2017 at 5:29 am
    • Jan Heine, Editor, Bicycle Quarterly

      The TRP HY/RD offer the same stopping power as hydraulic discs, but without the hydraulic lines. When we’ve used them on test bikes, there were really amazing. A local bike shop tells me that they are hard to keep adjusted, though.

      January 10, 2017 at 6:19 am
      • frostewistrom

        I use the brakes mentioned above and second that they are hard to keep adjusted. They also have very long lever throw.
        One thing that I would add to your list is the importance of using good compressionless housing for disc brakes.
        My allroad bike that is being built this spring will have hydraulic disc brakes so that u can run wide tires.

        January 10, 2017 at 6:53 am
      • John B.

        What aspect of adjustment are they referring to, do you know, Jan? We have Hy/Rds on four bikes in the house, including two tandems, but I have no adjustment complaints. Indeed, they require far less attention, in my experience, than is involved in keeping the pads adjusted on Spyres, for example.
        The one exception to this is that one seal or piston (out of 16 – 8 calipers with two seals and pistons each) can be a little sticky and needs periodic “exercising” and lubrication.

        January 10, 2017 at 7:42 am
      • Frank

        I have Hy/Rd as well. They are very fine brakes but indeed a little fussy maintenance-wise, in my limited (one year) experience.

        January 10, 2017 at 10:33 am
      • John B.

        @Frank What maintenance did you need to carry out on Hy/Rds?

        January 12, 2017 at 1:51 pm
  • grant

    another disadvantage of disc brakes is that you can’t run a lightweight radial-laced spoke pattern on the front, you need a wheel with crossed lacing to deal with the torque that originates from one side only.

    January 10, 2017 at 5:39 am
    • John S. Allen

      The difference in weight with radial vs. crossed lacing is very minor, about 12 grams. That is due to the added length, about the same as that of two spokes — see http://sheldonbrown.com/rinard/weights.htm. The issue of consequence is the need to dish the front wheel, weakening it unless the axle is longer than has been standard with rim brakes.

      January 10, 2017 at 7:00 am
      • Ed B

        The very significant advantage of radial lacing compared to 3x is aerodynamics.

        January 10, 2017 at 4:02 pm
        • Jan Heine, Editor, Bicycle Quarterly

          Have you seen any actual testing on this? I used to lace my front wheel radially many years ago, when I first started building wheels. I have been looking, but have never seen anybody compare the same spoke type, rim type and spoke number, crossed vs. radial. All the comparisons I have seen were box-section rim with 32 crossed spokes vs. 16-spoke aero rim. So many variables were changed that it was impossible to say which variable had how much influence.

          January 10, 2017 at 4:08 pm
    • Conrad

      More importantly from a weight standpoint: you can make judicious use of light (17 gauge) spokes with rim systems. Probably shouldn’t do that with discs.

      January 10, 2017 at 8:59 am
      • kurtsperry

        Consider the full load path between where the braking torque is reacted into the frame and the contact patch of the tire, which is of course why skinny spokes and discs are a bad combo. This is seldom done when brakes are discussed.

        January 10, 2017 at 1:06 pm
  • marmotte27

    Great and very complete post.
    One more disadvantage of cantilever brakes like the Tektro CR720 I have on my bike is the annoying squeal when braking at faster speeds. No amount of toe-in adjustment or whatever seems to be able to get rid of it.

    January 10, 2017 at 6:16 am
    • Jan Heine, Editor, Bicycle Quarterly

      The Tektros are not the best design, and they flex a lot. I’d try to use _even more_ toe-in to try and get rid of it. Really good cantis don’t squeal when set up correctly.

      January 10, 2017 at 6:18 am
      • Pawl Bearer

        I struggled with brake squeal on Shimano LX V-Brakes on a Surly fork. No amount of toe-in would work. There was over 5mm of toe-in and it would still squeal. The brake pad wouldn’t even contact for half the length. Then I tried reversing the toe in so the rear edge of the brake pad contacted first and the squeal went away. Brake performance and stopping power also improved because the entire pad was contacting the rim. “Toe-out” sometimes works better than toe-in. The rear brake still works good with normal 1-2mm of toe-in.

        January 10, 2017 at 7:08 am
      • Heather

        I had LX canti brakes on my surly and they squealed to no end. I also did not find them strong enough, but it could have been a brake lever power issue. I remember going down steep hills in terror, which I do not do on my old road bikes with ‘mcguivered’ side pulls.

        January 10, 2017 at 12:42 pm
      • marmotte27

        Hey, I’ll try the toe-out. More toe-in, as suggested by Jan, would make wheel removal difficult as the brake shoes hit the fork blades when the brakes are opened up.

        January 10, 2017 at 11:33 pm
      • Peter Chesworth

        Two unrelated issues … first, would be interested to hear of recommendations of good cantis that also deal with the fender/ Nitto N12 rack conundrum as a replacement for 720s.
        Second, Jan, the picture on pages 18-19 of BQ58 would make a brilliant poster.

        January 12, 2017 at 3:30 am
  • Chris Bussiere

    Jan, I really wish you would have been more specific about the make and model of each brake that was tested… this article is full of generalizations that can each be attributed to setup more than the base technology. It would have been a far more helpful article if you had listed the setup that was tested… for instance, disc brake pad wear is HIGHLY dependent on pad material and manufacturer. Choosing the right material for both the pad and the rotor makes a large difference in pad wear and braking performance!
    Some other comments:
    -In nearly 20 years of mountain biking with disc brakes, I’ve damaged a hydraulic line approximately 3 times… all of those were the result of heavy crashes that would certainly have ALSO damaged a cable. I think your ‘fragile hydraulic line’ comment is highly overstated (IMHO)
    -Re: ‘grabby’ – this is SO dependent on pad/rotor size and material that it cannot be such a general statement. Some pad/rotor combinations have incompatible material/textures and so being specific here is important.
    -Pad rub/wear is also highly dependent on pad/rotor material/size… I’ve run my road discs for 4000 miles and the pads are barely 1/2 worn (at a combined rider/bike weight of nearly 250lbs!). It’s also noting that pad run with discs has a much smaller effect than pad rub with rim brakes, the power lost to brake rub on discs is near-zero whereas the relatively soft and grabby rubber on rim brakes is far worse.
    One other key advantage that you missed regarding disc brakes is the ability to use an actual _suspension fork_… something that is VERY hard to do with rim brakes. The Cannondale slate is a great example of how this technology enables another… this eliminates the ‘flexible fork issue’ and greatly increases the bikes capability!

    January 10, 2017 at 7:11 am
    • Jan Heine, Editor, Bicycle Quarterly

      I really wish you would have been more specific about the make and model of each brake that was tested.

      You’ll have to read the 20+ Bicycle Quarterly articles. 😉 Really, there is just too much information for a single blog post. The goal here is to provide some general ideas about the technologies. Both disc and rim brakes can have issues, and all those issues can be solved. But the reality is that on many bikes you buy, these “generalizations” hold true. Understanding the issues is the first step to getting a great setup, whether you choose disc or rim brakes.
      As to suspension forks, you are right, but for road riding (and that is what this post is about), they still are a very unusual setup.

      January 10, 2017 at 7:23 am
      • Tamaso

        Has BQ ever featured a substantive discussion of disc pad material or rotor characteristics (other than size)? If so, please direct folks to the issue because I really do not recall it. These are both key components of disc performance, wear.

        January 10, 2017 at 8:18 am
        • Jan Heine, Editor, Bicycle Quarterly

          Usually, we just test the bikes the way the makers send them – except we replace the tires, because tires affect the ride so much that otherwise, we’d just be testing tires. So we haven’t been able to do a thorough test of rotors and pads.
          However, most riders also ride the bikes the way they are set up by the bike shop – similar to our experience, except you expect a manufacturer to set up a test bike for a magazine with a little extra care, knowing that about 20,000 people will read the Bicycle Quarterly review. Telling the average cyclist that they an experiment with pads and rotors and housing to solve the issues of the brakes doesn’t help much. Most cyclists just want to buy a bike and ride it!

          January 10, 2017 at 8:23 am
    • Jeff

      I’ve had no problems running vee rim brakes with my 98 SID Rock-shock suspension fork Chris. It is still running mint. In fact the first generation “Disc” SID’s suffered premature stanchion wear with all the flexing on the disc side. This topic seems to have taken a wider scope than it was first intended! We all know that some pads last longer than others so its hard to generalise. I have (due to poor choice) cut out both canti and disc pads inside 1.5 hours before. My guess is that we don’t really need overly supple forks if we are running a big fat tire on the front like a rat-trap-pass or something like that. I have disc tabs and canti posts on one of my 26 allroad forks, but I run the vee brakes because its a lot lighter and given the application, discs are overkill, even though they are easier to maintain, adjust and set.

      January 12, 2017 at 6:42 pm
  • Woody Peterson

    Great topic. Here’s one other thing I encounter as a commuter on rim brakes:
    I’ve dialed in some cheap mini-V’s paired with newer Shimano levers which have a bit more cable pull, and have all the stopping power and modulation I need – *so long as everything is clean*. For every day commuting in even just misty weather, a slime builds up on the rim. I can brake hard to clear the slime off for a little while, but with just a few days’ buildup I can lose a huge amount of stopping power, to the point where I won’t be able to stop at the bottom of hills until I clean my pads and rims.
    It only takes me about 15 minutes to take the pads off, scrub them down, wipe the rims down, and put everything back together, but it’s messy and yet another chore to do in an already busy life. This alone is making me pine for disk brakes.
    Is this a solvable problem?

    January 10, 2017 at 7:12 am
  • Stefan Hackenthal

    Good article, Jan.
    I have one problem with hydraulic brakes. Currently I have two brake levers for each brake (one in form of race braske levers (105) and additional ‘satellite’ levers on the top of the handle bar. As far I know there is no hydraulic product for this requirement. Could the TRP HyRd handle tow brake levers?
    Greetings from Hannover, Germany

    January 10, 2017 at 7:14 am
  • Pete

    Interesting summary Jan. Have you seen this account of brand new pads being worn out completely in a singe gravel group ride? http://www.bikeradar.com/road/gear/article/horse-for-the-course-focus-cayo-disc-for-buttergold-44175/

    January 10, 2017 at 7:22 am
    • gregoryvanthomas

      Some bike magazine, a British one, I believe, tested Shimano and SRAM disc brake pads in muddy conditions. The hypothesis was that their sintered pads would last and their organic or resin pads would not.
      Turns out that the SRAM organic pads lasted no time at all, and their metal sintered pads made it a couple hours. Shimano resin pads outlasted the SRAM sintered pads by a lot (finished the day I think) and their metal pads just showed some wear by the end of the day.
      Not all pads are created equal.

      January 11, 2017 at 9:54 pm
  • 47hasbegun

    It should be mentioned that pad composition is important for both disc and rim brake pad life. Most disc brakes come with resin pads that offer shorter life and worse performance in the wet. It’s usually best to replace them with sintered metal pads, which may also require procuring rotors designed for the pads as stock rotors usually can’t handle them.

    January 10, 2017 at 7:30 am
  • George Chomacki

    Jan, I’m hoping to have a custom 7 cycles bicycle built. I can specify any brake & they’ll provide proper braze-ons etc. I would really like rim brakes. Can you recommend any that would fit a fendered 650bx42 wheel? A 26xapprox 2-inch fendered wheel? It seems that I’d be looking for some sort of cantilever set-up, but if so, which ones? Or are there any centre-pull ones that you’d use yourself for such a build?

    January 10, 2017 at 7:30 am
    • Jan Heine, Editor, Bicycle Quarterly

      We offer the Compass centerpull brakes, which we feel offer the best braking power and modulation, plus lightest weight and best tire clearance. You can read more about these brakes here. One issue is that titanium mounting posts aren’t available off-the-peg right now, but we are working on that. In the interim, it wouldn’t be hard for a good builder to machine a set for your bike.

      January 10, 2017 at 7:38 am
      • George Chomacki

        They suggested a steel fork if I wanted to go with the Ti frame, but in this case a non-issue since I’m considering their steel frame. Thanks for your advice.

        January 10, 2017 at 9:10 am
        • Jan Heine, Editor, Bicycle Quarterly

          Steel forks are a great option even for ti and carbon frames. You simply have more choices as far as geometry and “passive” suspension are concerned.

          January 10, 2017 at 9:15 am
    • HaloTupolev

      >”A 26xapprox 2-inch fendered wheel?”
      The easy solution is canti posts.
      Linear pull v-brakes with long arms would do the trick, and are very easy to set up and get huge power out of. I’m using Deore T610 with Rat Trap Pass EL (53mm inflated) and full-length fenders on a rigid MTB drop bar conversion. That’s about the maximum tire size I’d personally use on this setup, though, bigger would lose the healthy clearance.
      If you need more room and are okay with centerpull cantis, they can provide a LOT of clearance.

      January 10, 2017 at 2:24 pm
  • Justin Hughes

    It’s worth noting that rim brake and disc brake rims of the same material (aluminum or carbon) are comparable in price, but for the same price the disc specific rim will not only be much lighter (as you say), but will last through multiple replacements of their rim brake counterparts. This makes them effectively cheaper in practice.
    All things being equal larger rotors should increase brake effectiveness and modulation. But things are seldom equal. Cable actuated hydraulic calipers are a step up on a purely mechanical disc caliper in this regard.
    Another advantage of disc brakes over rim brakes is the ability to run wider rims. On all but a custom bike with strategically placed cantilever/linear posts, you are effectively limited to a rim with an exterior width of ~25mm resulting in an interior width of ~20.5mm. In the opinion of many who have actually tried and used wider rims, i18-20 rims are not optimal for 48mm+ tires. Rim brake power and modulation is affected by the width of the rim; not so with disc brakes.
    You are using TRP Spyre on your Firefly? What size rotors front and rear? I found they were exceptional with 180/160 rotors and 11s DoubleTap levers. If you find them lacking (and this is a much more common complaint by those using Campagnolo Ergopower levers which have a slightly shorter cable pull than Shimano or SRAM) you might consider trying the Yokozuna Motoko or the Ashima version. I am not convinced, for my own use, that a fully hydraulic brake system is advantageous in the aggregate. If long, long descents are a regular part of one’s riding a fully hydraulic system becomes more attractive.
    A factor with both rim brakes and disc brakes is how performance is affected on each with the use of different brake levers. This seems to be more prevalent on the disc side, but really is not a fault of either the rim or disc brake. Still, it can result in unimpressive performance when the owner or mechanic are not adept at setup/adjustment of brakes and the subtleties between various calipers and levers. The importance of zero compression housing on cable actuated disc brakes cannot be overstated. This type of housing is more expensive so can be considered an advantage of rim brakes, but rim brakes also benefit from compressionless housing. Also, options like Jagwire Elite Link are effectively permanent and one only needs to replace the liner and cables when worn out.

    January 10, 2017 at 7:33 am
    • Jan Heine, Editor, Bicycle Quarterly

      As I mentioned in the post, I agree that rotor size is crucial, and most road bikes with mechanical discs are too small in that respect. We tested the Jones with a Shimano mtb mechanical disc and 200 mm rotors. It offered great stopping power, but the brakes were a bit too grabby. The Firefly, Pechtregon and Moots all had 160 mm rotors and (mechanical) TRP Spyres, and braking power wasn’t quite optimal. So I think you are onto something with your 180 mm rotor. On the rear, I can lock up the wheel with very small brakes – even 140 mm rotors are bigger than needed. (But if you use the rear brake to keep your speed in check during long descents, the larger rotor may be useful to dissipate the heat.)

      January 10, 2017 at 7:43 am
      • Benz Ouyang

        Jan, I’ve been meaning to ask if you ever took the time to properly bed in those disc brake pads before testing. I found proper bedding in is critical to disc brake performance, and can be the difference between “great brakes!” and “I’m gonna die!” (on the same exact bike).
        I have both mechanical (Avid BB7) and full hydraulic (TRP Hylex) discs on 160-200mm rotors; both brakes are great with bedded in pads (more than enough power to flip the bike with good modulation) and both are dangerous with new “out of box” pads, making me think it’s really the prep of pads that you may be missing.

        January 10, 2017 at 9:28 pm
        • Jan Heine, Editor, Bicycle Quarterly

          I’ve ridden the Spyres on three different bikes, with four different sets of pads. I fully expect a brand-new brake pad not to offer full braking power, but on my Firefly, the pads were worn down beyond the safe limit, without braking power having improved. It’s always adequate, but not as good as it could be. The other two bikes were set up by their makers, and both had significant miles on them before I rode them… so I don’t think it’s the bedding of the pads that is the problem.

          January 10, 2017 at 9:36 pm
    • Winston W Lumpkins IV

      The day I manage to wear out a rim brake wheel by wearing out the braking surface and not denting or cracking the rim beyond what is safe to ride will be a very fine day indeed.
      For some riders who are more skilled/ride on nicer roads than I, that might be a concern, but for me…

      January 11, 2017 at 5:57 pm
      • Jan Heine, Editor, Bicycle Quarterly

        A lot depends on tire width. Since riding a minimum of 42 mm-wide tires, my wheel maintenance (truing, etc.) has been reduced to zero.

        January 11, 2017 at 11:00 pm
      • John B.

        I wore out the sidewalls of an almost brand new Velocity A23 rim in one day. Admittedly, it wasn’t your average day, but rather 200 miles on very hilly/mountainous dirt roads in apocalyptic conditions. My (for the record: very skilful) friend completely wore out a brand new set of (rim) brake pads in just 100km on the same day, specifically the stock pads on Vélo Orange’s Grand Cru brakes. In yet another occurrence on that day, another friend blew out the sidewall of his tyre when the pads on his Paul Racer centrepulls wore enough to allow the pads to swing into the tyre.
        Also on a somewhat esoteric level, a rainy fortnight touring in the Swiss and Italian Alps was also sufficient to wear rim sidewalls to a scary level. On a more mundane level, my commute route used to feature several descents with 10+% gradients which ended at stop signs, causing me to replace Velocity Dyad rims annually.

        January 12, 2017 at 1:45 pm
  • Tom_Anhalt

    Great review, Jan.
    The only part I might not agree with is the assertion on the weight issue ofit being possible to overcome the hub, spoke, and braking disc weight additions by changing the rim design since it doesn’t need to handle braking loads. So far this hasn’t been shown to be the case. For example, Enve just came out with a new carbon disc-specific wheelset where although the rim is lighter (and claimed to be more aero) than their equivalent rim-brake rim, if you look at the overall wheelset weight (including braking discs) they are still significantly heavier than their equivalent rim-brake wheelset. The additional mass of not only the rotor, but also the added mass to the hub to mount it, along with additional spokes required (for equivalent strength under braking) are a LOT to try to overcome. In the end, in an “apple to apples” comparison, a disc brake system adds ~1lb, or more, to an equivalent rim braked bike/system.
    Also, I too highly recommend the use of compressionless housings (such as Jagwire Link) for use with mechanical disc systems.

    January 10, 2017 at 7:55 am
    • Justin Hughes

      The 1lb disc weight penalty simply does not hold water any longer. I recently spec’d a custom steel frame and I calculated the total weight difference in the completed bike with Compass centerpulls versus Yokozuna Motoko disc calipers, including the braze-ons, dropouts and mounting tabs/posts required, all pieces required to make the brakes functional, etc result in an estimated penalty of ~355g on the brakes (I consider the rotors as part of the braking system) and required frame pieces, and a weight advantage on the wheels (rims, spokes, nipples, hub, rim tape) of ~200g for a net penalty of 155g or about 1/3 of a pound. Every project will be different, but the generalization of an entire pound weight penalty isn’t accurate. More weight can be saved on the wheels and more weight can be added with different disc caliper designs, but it seems to me the average weight penalty is significantly less than a pound all said and done. There is definitely a penalty, but it is grossly overstated and, in my case, will constitute a total weight penalty of about 1.5% of the total, unloaded bicycle weight which is not significant.

      January 10, 2017 at 8:43 am
      • Tom_Anhalt

        I think you’ll need to probably gives us more details on your particular tradeoffs, because it doesn’t like you were quite doing an “apples to apples” comparison. For example, on the Enve SES 3.4 wheels I mentioned above, with King 45 hubs on both, the increase in weight for the disc wheelset over the rim brake version is 80g (1514g vs 1435g) NOT including the braking discs and hardware (why not include braking discs in the wheel weight?…rim brake rims come with the braking surface integrated, so it’s fair to include in wheelset weight).
        Also, if you look at any large production bikes that have both rim and disc brake versions, the disc versions are invariably at least 1lb heavier.

        January 10, 2017 at 10:01 am
      • Justin Hughes

        @Tom_Anhalt, It doesn’t matter to which component group you attribute the weight. Do what you like. The total weight of the operational bicycle is the the total weight. Apples to Apples cannot/should not be done by the very nature of the comparison. Why would I choose a disc version of a rim brake rim (like an A23) when I could save weight and increase rim width with a different design that is allowed because a brake track is not required?
        I’m not trying to argue for or against disc brakes on any application, just sharing some data points. My 32h 3x, centerlock, thru axle, 23mm internal, dynamo front, 11s Shim/SRAM rear, SP PL-8X, Sapim Race, brass nipple, Pacenti rim tape wheelset weighs 1818g (982 front, 836g rear). The difference comes from the rims. There are no aluminum, rim brake compatible, 23mm internal rims that come close to 341g (actual not just published) like the ones I was able to use for this application. The DT350 centerlock rear has a claimed weight 15g heavier than the published weight of the same hub in a non-disc version. This was compared to my friend’s rim brake 32h 650b, QR Dura Ace/SP wheelset with the same spokes/nipples as I used which weighed 2020g.
        If you want to “weight” the location of the weight, I think it’s generally agreed that, on a bicycle wheel, the closer to the center of the wheel (hub) the weight is concentrated, the less effect the additional weight has versus heavier rims or tires, for example.
        There are lots of little pieces one must account for if you want to try and compare the setups such as straddle cables and hangers, ISO adapters and ISO/post caliper mounts, brake shoes and pads, mounting hardware, rotors, additional housing/cable, and on and on. With things relatively equal (set up for same riding conditions, same rider, etc) the disc brake bike will be heavier. But, by a pound? Certainly not for the type of bike I am building.

        January 11, 2017 at 11:10 am
  • Gugie

    I built an all-road frame with disc brakes last June. Doing a pre-paint test build, I found that the front rotor came extremely close to rubbing on the fork blade (I used one of Anvil’s excellent disc jigs to properly position the mount). Some friends mentioned that they had wear marks on their forks from disc rubbing as the fork flexed – perhaps during cornering? At any rate, this lead me to braze in a 1mm spacer on the inside of both fork dropouts, which eliminated this issue.

    January 10, 2017 at 8:16 am
    • Wai Sing Lee

      The brazing on of a spacer is something that some builders will do.

      January 12, 2017 at 10:12 pm
  • Nestor Czernysz

    Thanks for the general overview. One aspect is separating brake force and brake power in tests.
    Some tandem disk brake test were done in the early 2000’s, which unfortunately seem to be no longer on line. I have hard copies somewhere. Shimano has published some data related to brake power.

    January 10, 2017 at 8:18 am
  • Alex Wetmore

    I’m using a wheel swap on the Elephant NFE to go between 559mm rims with studded tires when there is a risk of ice and 584mm rims with Compass Switchback Hill tires the rest of the time. The smaller wheel diameter gets me huge fender clearance (helpful if there is actually snow) and there are better and cheaper studded tires in 559mm than 584mm. It’s nice being able to swap wheels in a couple of minutes rather than remount the tires, and it’s better than my old approach of commuting on my MTB (including suspension fork) on icy days in the winter.
    Otherwise I can’t think of many reasons where I’d switch rim sizes.

    January 10, 2017 at 8:22 am
  • Bruce Rinnert

    There has long been a belief expressed that disc brakes and wheels result in higher stress levels for spokes. For this reason riders who do heavy loaded touring have been discouraged from having discs because of more frequent spoke breakage. As most know, typically spokes when they fail do so at the end connecting to the hub flange – with the added uneven torque on a hub flange of a disc wheel coupled along with excess weight from luggage carried, it seems like a recipe for more problems. With this said, I recognize with the current popularity of disc brakes many production bicycle companies are now offering so called ‘touring’ bicycles equipped with them.
    While I realize most of your research and orientation is not usually with loaded bicycle touring I would greatly appreciate some findings on this issue.
    With best regards!

    January 10, 2017 at 8:27 am
    • Jan Heine, Editor, Bicycle Quarterly

      I do tend to brake very hard, since I don’t like to lose speed until I have to. So we’ll see how those spokes on my Firefly will hold up in the long run. One reason I bought a disc brake bike is so that I could gain first-hand, long-term experience. This isn’t something you can test over a few weeks!

      January 10, 2017 at 8:33 am
    • Tom_Anhalt

      They cause additional tension variation in the spokes since they need to transmit braking torque to the rim from the hub, unlike a rim brake system. This is also the reason why for an equivalent “strength” wheel build, one will need to add spokes, and also why radial lacing is a “no-no”.

      January 10, 2017 at 10:04 am
      • Justin Hughes

        I suppose this could be the case with road racing wheels. For my own bikes, I build 32h 3X wheelsets whether they are rim or disc brake specific.

        January 11, 2017 at 11:14 am
    • John S. Allen

      Spoke stress due to braking can be calculated, at least roughly. Let’s throw some difficult-case numbers at the problem: 1.0 G braking is about 40% more than can be achieved on a solo bike without a skid or face plant, and is entirely with the front brake, as the rear wheel will lift. With a 250 pound bicycle and rider, the spokes will have to resist 250 pounds of deceleration. Now, assuming a rim diameter of 500 mm (about right for an MTB) and hub spoking diameter of 40 mm, the stress on the spokes due to braking will total 3,125 pounds. Trailing spokes will be loosened and leading spokes, tightened. The tension change for each spoke in a 32-spoke wheel will be about 100 pounds. All the weight of the cyclist and rider will be on the front wheel; the 3 or 4 spokes at the bottom of the wheel will share the weight load through reduction of tension. Therefore, the weight load will not increase the likelihood of spoke failure due to overtensioning but it could result in spokes’ going completely slack and losing control of the rim. Trailing spokes will have to be under approximately 200 pounds of tension to avoid going slack, and leading spokes will have to withstand 100 pounds more than in an unloaded wheel. 250 pounds tension when unloaded is about right for spokes with 2mm shafts and so these numbers check out OK — but the loads on spokes could be higher if the hub barrel is not rigid in torsion, or with a heavier rider or a tandem. Solution: more spokes.

      January 10, 2017 at 10:13 am
      • John S. Allen

        Got it backwards: tension increase at the rear of the wheel! The hub is trying to drag the wheel forward….

        January 10, 2017 at 10:36 am
    • John S. Allen

      Couple more points: the calculation I made applies only to a hub brake — spoke stress is much lower with a rim brake; the 3,125 pounds of spoke tension change which I described is due to torque transmitted from the rim to the hub. I neglected also to mention the 250 pounds due directly to deceleration — but this is of little consequence, as it is shared among many spokes through tension increase at the front of the wheel and decrease at the rear. The tension change on any one spoke due to this probably doesn’t amount to more than 20 pounds.

      January 10, 2017 at 10:34 am
  • Conrad

    What is going to be the optimal brake for the rat trap pass tire? Discs are absolutely the way to go with a suspension fork. For a well designed steel fork (meaning, not over built to accommodate the greater forces of disc brakes) , I think a rim brake is still the way to go. Are we going to get an oversized center pull? Resurrect the roller cam? Currently I use v brakes with cane creek v brake levers. Works well but hard to set up around a front rack.

    January 10, 2017 at 8:28 am
  • Chris V.

    I really love my disc brakes! But I don’t live in a mountain state. OTOH I have ridden off road in places such as Colorado and I’ve never had a problem with my MTB hydro discs. So, when I think about why my experiences with disc brakes are so positive, while others have had negative experiences of differing levels, I think about two plausible conclusions.
    1. I don’t ride as aggressively as those who have had negative experiences (as fast, or in as aggressive of terrain).
    2. I don’t demand the level of perfection from my brakes that others do (I don’t perceive a problem to be there with my brakes that others would report).
    I do find it hard to believe that disc brakes can’t be a superior option for road bikes. But I understand that there are design updates that need to be made and updated technologies that could improve discs on road bikes. While not scientific, I really like the argument that discs have proved themselves in the MTB world, and they are now the only option most riders at any level will consider. And while there are those who like to use the “the bike industry is making us use discs on mountain bikes” argument. I think this type of conspiracy argument is only made by a small number of riders who may have personal experiences that sway them away from discs, but really are not valid to the greater cycling community. In the pro road racing scene I feel like the discs will cut the peloton to shreads is a good example of fear and conspiracy beliefs that really don’t apply statistically to the real world.
    But these are just my little opinions the WWW.

    January 10, 2017 at 8:47 am
    • Jan Heine, Editor, Bicycle Quarterly

      Mountain biking is a totally different sport. For example, when using suspension forks, disc brakes really make sense. Conversely, with “rigid” forks, disc brake forks really need to be rigid and stiff, while rim brake forks can be built to offer an amazing amount of compliance on things like expansion joints and roots…

      January 10, 2017 at 9:09 am
    • Tom_Anhalt

      In the case of road RACING (i.e. road races, TTs, and even triathlons), there are also the aerodynamics and weight considerations that Jan rightly didn’t consider in his review (for the purposes he is discussing). A racing bike where the rim brakes are well integrated into the aerodynamics of the bike will always win out over discs in those regards. That’s something the industry is currently trying to “paper over” in the push towards universal “separate braking disc” adoption.

      January 10, 2017 at 10:08 am
      • Jan Heine, Editor, Bicycle Quarterly

        The aerodynamics of the bike are over-rated by most, but it’s interesting that when it comes to disc brakes, the same people who argue that a 32 mm tire will be less aero than a 28 (without much evidence) aren’t concerned about all that hardware sticking out in the wind.
        The truth is that the aerodynamics of a bike are almost entire determined by its frontal area, and that in turn is determined mostly by the rider.

        January 10, 2017 at 3:16 pm
      • Tom_Anhalt

        Well, remember that I was referring to road RACING bikes, where every second matters (ask anyone who’s ever pinned on a number for a TT and lost a place by 1, or a small handful, of seconds 😉 In those cases, the participants have already mostly optimized their positions and clothing (the largest determinants of drag) and are looking at every other aspect for the “large number of small improvements” that add up to something significant. As it stands, in a comparison of a bike “optimized” around rim braking (e.g. something like a Trek Speed Concept, or even their new Madone road bike) vs. a bike “optimized” around disc brakes, the differences in aero drag can result in up to 1-2seconds/km of time difference over a fixed course length. That’s nothing a racer will want to ignore. For this reason, I highly doubt we’ll be seeing disc brakes on TT bikes for road racing. Yes, there have recently been triathlon bikes introduced with disc brakes…but, then again, the tri market is a whole ‘nuther beast anyway (and logic isn’t necessarily a driving factor in that market) 😉
        Now then, for the vast majority of other types of riding (as we are discussing here)…yeah, there are other, more important features to concentrate on than aerodynamics 🙂
        As to the aerodynamics of a bike being determined mostly by it’s frontal area, don’t forget that the drag at a given speed is determined by the object’s shape, as well as it’s frontal area. ..it’s not just the “A”, but the “Cd” (or drag coefficient) in “CdA” that matters. This is why deep frame, or wheel sections, are lower drag than shallower, more round sections of the same frontal area. It’s also why riders can have large differences in CdA for minor differences in frontal area, such as when raising or lowering the aero bars. Just something I thought I’d point out…

        January 12, 2017 at 7:46 am
        • Jan Heine, Editor, Bicycle Quarterly

          As to the aerodynamics of a bike being determined mostly by it’s frontal area, don’t forget that the drag at a given speed is determined by the object’s shape, as well as it’s frontal area. ..it’s not just the “A”, but the “Cd” (or drag coefficient) in “CdA” that matters.

          Technically, you are correct, but in practice, Cd is almost impossible to improve on a bike, because a cyclist generates such turbulent airflow. A cyclist’s Cd is 0.9 where a modern car is 0.3. When Bicycle Quarterly tested different setups and positions in the wind tunnel, we tried adding fairings, but they just made things worse! Basically, we couldn’t smooth the airflow, and the fairing increased the frontal area slightly, so the overall drag was greater with the fairings than without!
          The one thing you can change easily on a bike is frontal area, which is why riding in the drops is (slightly) faster than riding on the hoods, and why aerobars (or the aero tuck) are so effective.

          January 12, 2017 at 11:17 am
      • Tom_Anhalt

        I respectfully beg to differ that the Cd of a bicycle or a cyclist is “almost impossible” to improve. To add some detail to the final sentence in the response I gave above, I know that for my own time trial position, lowering or raising my aero bar position typically causes the drag to follow a linear trend (as one would expect with the changing frontal area). However, at a certain point, a mere 5mm change in bar height results in a nearly .020 m^2 change in drag (~equivalent to a 15-20W change to go the same during a race). Above and below that point, the changes are linear, but there apparently is a “break point” in Cd at a certain position. My speculation of why that is centers on the possibility that the change in bar height results in an early flow separation for the air traveling over my back, with a resultant dramatic increase in drag (i.e. Cd change). This would be something interesting to explore with some flow visibility techniques (i.e. “smoke”) in a wind tunnel run. This can be a highly individual thing, though.
        Additionally, for the bike, it’s well known that aerodynamically shaped objects can have dramatically lower Cd than, for example, round objects. This was brought home to me as I performed simple CFD analysis of different tubing options when I built my custom Stinner frame. Round tubes of a given diameter perpendicular to air flow are dramatically greater drag than well-designed “tear drop” shapes of the same frontal area.
        Here’s another example…it’s well known that a well-designed “bento box” structure placed behind a bicycle stem can fill in that low pressure area and drop the drag by a significant amount, all without change in frontal area.
        And a final example: one of the main reasons that a solid disc wheel lowers bicycle drag is that it acts as a type of “rotating splitter plate” behind the bike and rider, again with no increase in frontal area. It’s for this reason that Francesco Moser had one of his hour record attempt bikes constructed with a MASSIVE rear disc wheel.
        As to why your tests with fairings ended up they way they did…I haven’t seen that testing yet, so I can’t comment on that one way or another 🙂

        January 12, 2017 at 2:18 pm
  • Glenn

    Okay, I’ll speak up for the slobs who rarely clean their bikes: my disc equipped bike has such nice, clean rims!

    January 10, 2017 at 8:52 am
  • Tim

    There’s another advantage to disk brakes that I think is being missed here. If you manage to knock a rim out of true, your braking is unaffected. On the other hand for the same reason, the rim brakes do have some diagnostic value…
    It’s worth noting too that changing to a bigger rotor is not a big deal: an adaptor and a bigger rotor are all you need as long as it fits.

    January 10, 2017 at 9:44 am
    • Jan Heine, Editor, Bicycle Quarterly

      With big tires and a good wheel build, I find that “knocking rims out of true” just doesn’t happen. The last time I had that happen was when I taco’ed a wheel in a cyclocross race, maybe 20 years ago. And that wheel wasn’t going through the fork any longer, no matter the brakes!

      January 10, 2017 at 1:37 pm
    • Jeff

      For sure. I can remember looking at my rear disc one time, and being appalled at how out of true it was. No way it would have cleared any rim brake. I probably should have noticed it on the front.

      January 10, 2017 at 4:08 pm
    • Conrad

      I disagree. I see people with disc brakes rubbing in cross races all the time. My wide profile cantis never ever do that. They lack the power of discs but are much more reliable in nasty conditions.

      January 10, 2017 at 9:30 pm
  • drewdevereux

    Another downside worth noting of rim brakes is that they eat the structure that supports the tire. Eventually, the rim sidewalls get thin, and they can collapse, which can cause the tire to explode off the side. That can cause a crash, and/or at least an expensive wheel rebuild.
    I was told a story of a SF bike messenger who, while riding, heard a gunshot and found his calf bleeding. Bystanders called 911, paramedics arrived, and when all the dust settled, it was found that his rear rim had collapsed, and a shard of the rim flew off and was driven into this fellows leg.

    January 10, 2017 at 9:50 am
    • whippetanddachshund

      You’ve got to be really bloody slack / lazy / broke to let that happen though. There are wear indicators and a visual/running your finger on the rim inspection should be more than enough for anyone to realise their rim needs replacing. In the meantime my anecdotal evidence is that in the few months / 3-400 miles I’ve run disc brakes on one of my bikes I’ve just broken two spokes having never broken a spoke before in my life. I weigh ~66kg and I’m running 38mm compass tyres.. Maybe a duff wheel but seems odd to me.

      January 10, 2017 at 2:49 pm
  • Greg

    Good info but a couple comments…
    Another concern with road bike disk brakes: lack of modulation under wet conditions. As you pointed out, properly setup disk brakes are unaffected by wet and dry conditions. Unfortunately tire traction doesn’t work this way. A good friend and highly experienced road/mountain rider took a trip to the ER when his brakes locked his wheels and he went down. (Shimano Ultegra with 160mm rotors) I appreciate the advantages of disks for mountain, gravel, CX, and loaded touring; but for fast road riding/racing I think disks are a solution for a problem which doesn’t exist.
    I’m a huge fan of the v-brakes but unfortunately there are no brifters which have the proper cable pull. I’d love to see a brifter with a second pivot point to change the mechanical advantage (aka cable pull). I’m still in search of a “travel agent” like device with cleaner and less clunky lines but so far I’ve not found anything.
    Thanks for the insight on the centerpull brakes. I enjoy resurrecting old 26’er mtb’s into drop bar go anywhere road/gravel/trail bikes. I’ll have to see what I can find for a future project! 🙂

    January 10, 2017 at 9:53 am
    • John Vorobej

      Paul’s Crosstops and Strange brakes both had cam action links which changed the mecganical advantage during braking … Paul still may have a few and STRANGE designer Shawn Place now does gorgeous high end furniture …

      January 10, 2017 at 5:45 pm
    • Chris V.

      I use travel agent pulleys on one of my two cross bikes (the other has discs). See link below. I personally love them. And when I had them installed my mechanic was not hip on them until he installed them and tried the brakes out. I use the travel agents with XTR V-brakes.

      January 11, 2017 at 7:27 am
  • John Vorobej

    Overall , quite a good article but with certain glaring ommisions . As a certified retro grouch mechanic with a little OCD, two other variables should hae been mentioned with regards to mechanical discs and rim brakes. 1) Cable selection : In the infancy of mechanical discs , they all pretty much sucked but had the good fortune to co-exist with Shimano 2mm stainless braided brake wire and 6mm SLR brake housing; thus making them at least 50% better for offroad, all-condition braking. 2) Rim brake pad selection : I defy anyone to name a better wet condition brake pad than the venerable Scott-Mathauser red rubber/leather compound… properly set up, these pads will still out-perform anything on the market today … if you can find them 😉
    PS: where can I get a set of those gorgeous lace up mtb shoes ?

    January 10, 2017 at 9:57 am
    • Jan Heine, Editor, Bicycle Quarterly

      The red Kool-Stop pads we use on Compass centerpull brakes are the descendants of those Matthauser pads, and they still are the best for braking power.
      The shoes are made by Dromarti. They are my favorites.

      January 10, 2017 at 1:40 pm
      • John Vorobej

        I thought so ! Saw them at NAHBS ’10 and they have been calling to me to buy them ever since … I just forgot tje name is all 😉

        January 10, 2017 at 5:40 pm
      • B. Carfree

        Bah! They apparently don’t make them in men’s sizes. The largest size on their site’s drop-down menu was 47.
        -Says the Sasquatch whose American shoe size was the same as his age from 8-16, hence the line about men’s sizes. I envy you folks who get to choose from a variety of shoes. Those really are pretty and remind me of what I used to wear back in the ’70s and ’80s.

        January 10, 2017 at 7:22 pm
        • Jan Heine, Editor, Bicycle Quarterly

          For small makers, it’s hard to make and stock many sizes… but the Dromarti shoes are really great if you can fit them. (And to their defense, 47 isn’t all that small.)

          January 10, 2017 at 7:30 pm
  • randallisom

    I didn’t see this mentioned and wanted to weigh in. I ride in the rain quite a bit, after moving to disc brakes last year it seems like my tire sidewalls last longer as they do not get covered in road grime and aluminum/brake pad slurry from the rim brakes when braking in the wet. Previously my tires almost always entered early retirement due to sidewall failure, now I run pretty much to the cords under the tread with no sidewall issues.

    January 10, 2017 at 10:18 am
    • Benz Ouyang

      Not doubting you, but how does road grime and aluminum/pad slurry reduce sidewall life? I can’t figure out the mechanism, as I can’t see it as anything but superficial contamination.

      January 10, 2017 at 9:33 pm
  • Ian Bray

    Alternative solution: V brakes (Deore), hard pads (Swisstop) and Tungsten carbide rims (Rigida). Simple and cheap in the long term as pads and rims last so long, and no black goo in the wet. Work well with fat tyres too.

    January 10, 2017 at 10:49 am
  • Steven Krusemark

    A comparison of brazed on centerpull and cantilever brakes would be an interesting topic. I am adding new brakes to my 80’s Bill Boston Tandem with 650x42B tires and substantial fenders to replace the Phil Disks and would like to have the best stopping power for world touring. Disk brakes and hydraulics are not in my considerations, although the ARAI will go on the back as a third brake.

    January 10, 2017 at 10:55 am
    • Jan Heine, Editor, Bicycle Quarterly

      I think everybody who has used cantilevers and Compass centerpulls agrees that the centerpulls are better. Some other centerpulls (especially Dia-Compe) have a poorly-designed pivot location that results in a low mechanical advantage and poor braking. As always, if the system is poorly designed, it cannot perform as well as an outwardly similar, but better-designed brake.

      January 10, 2017 at 1:54 pm
  • Bill Lindsay

    It’s raining a lot in the Bay Area (CA), and as a result, the sidewalls of my great Compass Bon Jon Pass tires are filthy (rim brakes). It’s a bummer, but I meditate on Rule #9 and it makes me feel better.

    January 10, 2017 at 11:16 am
    • whippetanddachshund

      Don’t worry, my tan walls are filthy too and I’m running disc brakes..

      January 10, 2017 at 2:50 pm
    • Benz Ouyang

      The contaminated sidewalls are, as I found out, impossible to wash/scrub off later. However, they are the calling cards of cyclists who are disciples of Rule #9, and should be displayed proudly, whether in the wet or dry.
      (Or at least that’s what I tell myself…my poor OCD self…)

      January 10, 2017 at 9:37 pm
      • Jan Heine, Editor, Bicycle Quarterly

        My late friend George Gibbs at Il Vecchio Bicycles in Seattle had a product that actually cleaned the blackened sidewalls very nicely. I never found out what it was, because like you, I don’t bother to clean them. On my Urban Bike, I use black sidewalls, so the contamination isn’t as apparent. My other bikes see use in the rain, but not that much braking, so the sidewalls stay reasonably clean. Still, that is one advantage of disc brakes…

        January 11, 2017 at 9:01 am
      • George Chomacki

        OK boys, I give up. What’s Rule #9?

        January 11, 2017 at 5:12 pm
  • Eli Torgeson

    I will add that a disadvantage to rim brakes is that an untrue (or even dinged) rim poses a not insignificant issue. Besides giving an annoying pulsing feel, in wet conditions, the rapidly varying amount of brake purchase on the out-of-true rim results in poor modulation at best, and unsafe (alternately too little and too much friction) at worse, during mild and moderate braking. This is especially true for wet conditions.
    Jan, do you have the same criticisms of linear pull (v) brakes, that you do of traditional cantilever brakes? Conrad above notes the difficulty of using these with a front rack (as the center attachment to the fork frequently is at the level of the horizontal cable.) I have had good experiences with v-brakes in general. (There are some caveats to using a travel agent problem solver to adjust the cable throw that should be considered if traditional road levers are used, however.)
    Besides Shimano XTR, I have used the Paul Motolites for the times I went between 650b and 29er as well as now on my Rawland rSogn, to be able to go between 650b and 26er wheelsizes. I should note that the mechanical advantage is changed dramatically (not usually for the better) when going from one wheel size to the other, but it is can be a good workaround for a nondisc wheel size change.

    January 10, 2017 at 11:42 am
    • John S. Allen

      Caveat about the Problem solver: cable failure. The smaller pulley is way too small to avoid fatigue failure. I use the large pulley of Travel Agents to take shifter cables around corners — very helpful with the tortuous cable routing of my Bike Friday. The larger pulley is marginally safe for use with brakes, but check frequently for frayed strands.

      January 10, 2017 at 7:37 pm
  • Rob Krochenski

    It’s a great bike world we live in…nes’t ce pas?
    One aspect of this debate that concerns me, at least a little, is the difference of heat generated from rim & disc brakes. I once had a flat on my heavily laden expedition outfitted Troll equipped with top end SRAM V-brakes and travelling at a heavily controlled rate on a downhill stretch of logging rd. The rim was so hot It could not be touched. On the other hand, I remember a comment from Peter White that a disc can produce enough heat to fry at hub generator.
    I think about such things when I fantasize about another flight down BC’s 28 mi. Coquihalla.

    January 10, 2017 at 11:47 am
    • Luis Bernhardt

      Having ridden the Coquihalla a number of times during brevets, I don’t see any problem. The descent is pretty non-technical, with long curves and wide shoulders where you don’t even need to touch your brakes.

      January 10, 2017 at 3:36 pm
  • brad

    My gear is likely less expensive than the brakes and bikes in your review, however, I commuted on a Jamis Aurora Elite for a few years before it was stolen. It had Avid BB-7 road mechanical disc brake with 160mm rotors. Riding almost every day in all kinds of weather the bike seemed perfect, except for the disc brakes. Each and almost every time I had a flat tire I would listen to the brake pads ticking on the rotor for the rest of my ride. The ride probably wasn’t really negatively impacted, but listening to the brakes ticking as I rode drove me nuts. Sometimes due to time constraints, I would need to wait until the weekend to adjust the ticking brake. When I replaced the bike I made sure bought one without disc brakes. My Tekro 559’s brakes on my bike have never let me down and I now spend more time riding and less time adjusting. Just my 2 cents, but for my needs, I am really glad to be rid of the disc brakes.

    January 10, 2017 at 11:51 am
    • Andy Stow

      I also have a Jamis Aurora Elite, and the same problem. It’s really hard to keep the system all lined up.

      January 12, 2017 at 6:31 am
  • Jason Miles

    I think price points and availability will be the market driving forces. The bike industry in general seems to be moving towards disc bikes. I think quality, price, and availability will all be getting better for disc brakes.
    As you mentioned for rim brakes to match the breaking performance of discs with large tires you need to use centerpull brakes. The only production bike with centerpulls I could find with 30 min of searching is the Cycles Toussaint.
    The only positive growth I can see for rim brakes are the “direct mount” brakes following the Shimano standard introduced a couple years back. Have you had a chance to ride a bike with direct mount rim brakes? I have seem many favorable reviews. Most bikes with this standard don’t have clearances for large tires, but I am designing a brake for this standard that could conceivably fit a 32c.

    January 10, 2017 at 12:26 pm
    • Jan Heine, Editor, Bicycle Quarterly

      The direct-mount rims brakes on modern racing bikes basically are centerpull brakes – look at the pivot placement. Whether you activate the arms via a straddle cable (centerpull) or a linkage (direct-mount) doesn’t make a big difference. I am sure they work great – it’s the same design as our Compass centerpull brake.
      The Cycles Toussaint unfortunately is designed for a brake that is sub-optimal, so the braking isn’t great. And the pivots are in a different location than those of the Compass centerpull (which is the reason why the mechanical advantage is not as good), so it’s not a simple brake swap.

      January 10, 2017 at 1:59 pm
      • jasonmiles31

        Yes the pivot locations are in similar locations. Unfortunately as you mention with the Toussaint small differences in location and shape can have big differences in compatibility.
        Looking at the mounting locations the DM brakes pivots are spaced much more narrow than the compass mounts (49mm vs 75.5). The height of the pivots is difficult to compare as the only dimensions I have for the Compass mounts are based on a fork design with large fork offset and for I assume a 650B wheel size. Based on my calcs the Compass pivots are effectivly about 20mm lower which cannot be right.
        What is the brake reach range on the Compass brakes (pivot to pad)? The brake I am designing is 20-35mm.

        January 11, 2017 at 11:05 am
        • Jan Heine, Editor, Bicycle Quarterly

          Looking at the mounting locations the DM brakes pivots are spaced much more narrow than the compass mounts (49mm vs 75.5)

          Of course, the “direct mount” brakes are intended for narrow tires, the Compass brakes are for wide tires. It’s the design principle that is the same, not that the brakes are interchangeable.

          January 11, 2017 at 11:59 am
      • jasonmiles31

        Agreed, and I wish the DM standard had wider pivots but I think it was based on the left brake arm pivot location for a standard dual pivot road caliper.
        I would caution on evaluating a brake on design principle alone, as you mentioned the pivots locations on the Toussaint are not optimal but might appear to be in the correct location at first glance.
        Do you guys have any other drawings to determine correct pivot location for the compass brakes? The pivots on my Schwinn High Sierra are wider at 86mm and require a lot of brake reach. I could add the spring holders to the pivots pretty easily but I doubt they would be in the right location. Because I have 26″ rims it is also difficult to translate to your 650b fork drawing.

        January 11, 2017 at 2:26 pm
  • Bert

    You mention “the high price of carbon rims” if you want to keep the weight down while using discs. Don’t disc brakes make it more interesting to spend money on high(er) quality rims, since you don’t have the wear of two braking pads grinding down the sides of the rim? That kind of wear is often the main reason to replace rim brake wheels.

    January 10, 2017 at 12:31 pm
  • Heather

    I noticed that a lot of the new randonneurs and all roads have disc brakes, which made me think oh I’d like one….. not financially possible. Hydraulic discs require a lot of work and my husband worked in a mountain bike heavy bike shop. He did not trust them. He had a bike with mechanical disc brakes and he found them just as problematic and fussy if not more than most rim brakes. Pad would wear out and he’d be left with no braking power, winter grit, grime and de icer chemicals ate away at the more fiddly parts, the rotors bent….While initially things are grand, in time parts fail and disc brakes cost more to overhaul or replace. So rim brakes it is. With the age of our bikes I think we just grin and bear it.
    I am a heavy braker and have trouble because my hands are so small and am always hunting for small brake levers. I will be looking at long reach side pulls or centre pulls for some bike builds, and have read that the oft used tektro long reach brakes can be bendy.

    January 10, 2017 at 12:31 pm
  • Willem

    Thanks Jan for your experiences with a still very evolving technology. I think there is an intermediate technology that you do not mention: hydraulic rim brakes. My wife and my son have Magura HS33 hydraulic rim brakes and these are really great for loaded touring. Unlike them I prefer a drop bar, so I use the now discontinued HS66 drop bar version of the same brake. On an off road tourer I would probably go for hydralic discs, and on a rando bike I would opt for a lighter centrepull, but with camping luggage I think the HS66 is just perfect, with excellent stopping power and ditto modulation. I would be reluctant to expose discs to the kind of beating a bike gets on long distance train rides in Europe.
    For loaded touring some friends now also use V brakes with the Tektro drop bar levers for V brakes, and claim that these are superior to cantilevers. As long as you are using drop bars I think these deserve consideration if you cannot locate a pair of HS66 on Ebay.

    January 10, 2017 at 12:55 pm
    • Tom_Anhalt

      For hydraulic rim brakes, in addition to the HS33/66s you mention, for road uses there are also the Magura RT6/8C brakes, which have a “converter box” so that they can be used with any road brake lever/brifter, plus the SRAM Hydro-R rim brakes. I’ve used the RT6Cs in the past and currently have the SRAM S700 Hydro-R rim brakes on my road racing bike (custom Stinner). Both of those hydraulic rim brakes are excellent performers. I’m using the SRAM brakes with Hed Jet+ black rims, which have a machined textured surface and anodization on them, and the combination is arguably better performing (in power, modulation, and consistency wet/dry) than the discs (TRP Spyres) on my “all road” bike. These have shown me that most of the “benefits” many subscribe to disc brakes are really the result of using a hydraulic actuation.

      January 10, 2017 at 2:23 pm
  • niggle

    Why are v-brakes not mentioned in the article? Obviously there are no issue with big tyres and v-brakes, which are a proven, reliable, easily maintained and affordable solution in my opinion. There are no real reasons why STIs cannot be made with the right cable pull, the manufacturers just don’t make them that way. I use Shimano 90mm v-brakes on the front of both my bikes (and old LX low profile canti brakes on the rear where less power is needed/usable and v-brakes would clash with the rear rack brackets) and this works well IME. One bike has Campag Ergos and the other has Versa VRS 11 brifters for the Alfine 11 hub.
    Granted if you cannot do your own rim swaps that can be an expense in the long term, and a +1 to everybody who recommended compressionless housing for brake cables.

    January 10, 2017 at 1:04 pm
    • Jan Heine, Editor, Bicycle Quarterly

      There are a number of issues with V-brakes. In our applications, one of the most important one is that you cannot set the height of the straddle cable, so these brakes often don’t work well with fenders and front racks. They also suffer from the same issues as all cantis with fork blade/seatstay twist…

      January 10, 2017 at 3:10 pm
      • Albrecht

        Fork blade/seatstay twist easily can be reduced by cheap brake boosters. This improves the performance of Cantis and V-brakes significantly. All cantis and centerpulls suffer from brake shudder caused by slight bending of the fork during braking which leads to increasing tension of the cable. This can’t occur with direct pull brakes.
        This issue can be also mitigated by are cable hangers mounted to the fork crown.

        January 11, 2017 at 5:46 am
        • Jan Heine, Editor, Bicycle Quarterly

          The brake judder occurs when the fork flexes in the upper part (above the brake pivots) rather than the lower part. It’s a sign that the lower blades are too stiff, and the steerer tube is too flexible. With a well-designed fork, you won’t get brake judder. I have cantis and centerpulls on all my bikes but one, and none have ever exhibited the slightest brake judder. On the other hand, pretty much every Bicycle Quarterly test bike with a carbon fork and cantis had terrible brake judder.

          January 11, 2017 at 9:05 am
      • JoeG

        Seems like a well designed front rack using the canti posts for mounting could incorporate the brake booster function.

        January 12, 2017 at 2:16 pm
  • julianactive

    For me hydraulic disk brakes are the way to go. Of course most of my riding is on a mountain bike, but the power and feel and modulation that I get from my XT hydraulic brakes is the best I have ever experienced. I hated cantilevers and although v-brakes were an improvement I do not pine for the old days!
    I wore through several rims with rim brakes because sand, mud and water make a great file! I also hated when I bashed a rim or it went out of true and the resulting brake pulsing. I could never get much mileage out of rim brake pads on a mountain bike in bad conditions.
    I transformed my Ti 29er mountain bike into my “allroad” bike and use cheaper deore hydraulic brakes with 160 mm rotors. Even if the bike and fork were fitted for rim brakes I wouldn’t consider them. I use a rigid carbon fork setup on my bike.
    Brake pads are relatively cheap so replacing them is not that big of deal and they are smaller and lighter than rim pads.I get over a thousand miles on my mountain bike brake pads.
    Brake rubbing is the only real issue that I have with disc brakes but it is not a deal breaker for me. Adustment is the key and a bent rotor will make it worse.
    As far as hydraulic cables being fragile I don’t think that argument holds water (errrr oil!). A leak is more likely to happen near the lever or caliper than in the hose itself.
    I found cable activated disc brakes (Avid BB-7’s) to be much noisier than hydraulics probably because they use a fixed pad on one side.
    But if I were to tour the world I would probably go with a mechanical cable activated disc brake.
    Great write up with lots of food for thought.

    January 10, 2017 at 1:40 pm
    • Jan Heine, Editor, Bicycle Quarterly

      Brake pads […] are smaller and lighter than rim pads.

      What kind of rim brake pads were you using? The pads on my TRP Spyre disc brakes are much larger and heavier than the pads on my centerpull brakes. Replacement is easier, though, but it also need to happen at least 5x as often…
      I do agree that discs appear to be a great choice for mountain bikes.

      January 10, 2017 at 3:13 pm
      • julianactive

        Kool stops mostly. The avid BB-7 pads are smaller and lighter. Deore pads are small and light. XT pads are heavier because they come with built in cooling fins. But I must say the weight difference is negligible in the whole scheme of things.
        It is funny that front brake pads for my Toyota 4 runner are cheaper than my XT pads! Also tires for my car are cheaper and last longer than my bike tires!
        I wonder if the road brake levers for hydraulic brakes are not as powerful or as easy to modulate as the levers used on mountain bikes? I used to put on biking events and I often saw women struggling with the standard drop bar brake levers. Several went off the road due to insufficient braking power (this was with non hydraulic brakes)
        I don’t disagree with your findings when you talk about your compass brakes and good quality brake pads but most people stick with what came on their bikes. I guess the real question is does a thousand dollar road bike stop better with standard side pull brakes or disc brakes?

        January 11, 2017 at 10:24 am
        • Jan Heine, Editor, Bicycle Quarterly

          I guess the real question is does a thousand dollar road bike stop better with standard side pull brakes or disc brakes?

          I don’t know about thousand-dollar bikes doing anything great, but let’s double the price… and for a $ 2000 bike, I think it comes down to the tire width. If the bike runs short-reach brakes, I imagine that most modern dual-pivot brakes stop great. With bigger tires, middle-of-the-range disc brakes seem to perform much better than middle-of-the-range rim brakes.

          January 11, 2017 at 10:54 am
  • Christopher

    Given that well designed and correctly adjusted brakes of either type are effective at slowing and stopping bicycles, my decision to stick with rim brakes was made with my ears. Whether it’s a competitor bearing down in a cyclocross race or a distant banshee on the trails, I find the squeal of disc brakes extremely annoying, abruptly interrupting my enjoyment of cycling. Yes, my own rim brakes do squeal occasionally in wet or dusty conditions, but I find the sound produced much less discordant and aggressive – indeed it might even be confused with birdsong!

    January 10, 2017 at 2:11 pm
  • Luis Bernhardt

    The reason I installed a front disc brake on my commuting bike was to solve a recurring problem: a rim brake used all winter will significantly wear down the rim. I used to be able to get three years out of a good 700C rim; now, for some reason, I have been lucky to get just one. Cynical about rim manufacturers. Three years ago, I bought a disc brake fork and a BB7. Being on the fixie, I was used to braking only with the front wheel, so the bike was consistently stopped solely by its front disc brake. After two winters, the front rim was absolutely pristine, and the rear rim (stopped with rim brake) was in very good shape because it hardly got used. I now build all my front disc wheels with carbon fiber rims. And I’ve upgraded to a hydraulic Shimano 785 caliper (IMHO the BEST hydraulic road disc brake you can buy) paired with a TRP Hylex lever (the combination works great, and for a fixie/single speed, you don’t need to strip down an expensive Shimano lever). I still use a rim brake on the rear because for pavement use, which is what I mostly do, you simply do not need the power/modulation/added weight/sex appeal of a rear disc brake.
    As far as pad wear, I have gotten maybe 500 km out of an organic pad, but I have gotten over 8,000 km on a sintered metal pad. In dirty, wet, salty/gritty conditions, I have gotten 2,000 km out of the metal Shimano F03C pad (now superseded by the J04C). If I don’t ride consistently in the rain, I have gotten over 9,000 km and counting on a sintered metal pad (Brake Authority aftermarket) on my geared bike (TRP Spyre front disc, dual pivot rim brake on the rear, with no wear on the unused rear brake pads, of course).
    Disc brake noise: the Shimano disc brake will squeal when it (pads/rotor) get wet. The squealing stops when they’re dry. Start by mildly braking to get most of the water off before actual braking starts. When they squeal, ease off and reapply. The squealing will stop by about the third application. As far as the “ticking” noise, I’d check the tightness of the bolts holding the brakes. Sometimes they work loose. If not, the wheel has probably shifted in the dropout. Release the wheel, bounce the bike slightly, reapply the QR. Ticking should stop. If not, and the noise really bothers you, switch to a fork with a thru-axle. Or just readjust the caliper. A 5mm wrench and one minute will do it. Also, be aware that the BB7 is a piece of … It has one fixed pad and one moving pad, so the moving pad pushes the rotor into the fixed pad. Dumb. Get a Spyre (if you’re into mechanical); it has two moving pads.

    January 10, 2017 at 4:09 pm
    • john

      Concerning squealing of mechanical disc brakes: Are the TRP Spyre’s less prone to squeal due to the dual pad movement (vs. BB7s with one pad movement), or does it make no difference as it relates to squeal?

      January 10, 2017 at 5:08 pm
      • Luis Bernhardt

        You know, I’m not really sure because I don’t often use that bike in the rain if I can help it. On the times I’ve ridden it in the rain, I’ve just put up with the noise. In addition, I’ve never been able to do a fair comparison between Spyre and BB7 since the BB7 was on the fixie and got replaced by the Hylex, and then the 785. A year later, I had a geared bike built, and the only brake on it has been the Spyre (although I did experiment with a HY/RD but was unhappy that it required so much lever travel, even after multiple times filling the oil reservoir as much as possible). I’d say the Spyre squeals more (louder and longer) than the 785 (and I’m using the Shimano RT86 rotor on both bikes). I’m using the more expensive Spyre with the carbon fiber stirrup, and I don’t like the way the cable is crushed when anchored, my only complaint.

        January 10, 2017 at 6:54 pm
  • tjsmith44

    Maybe it would make good sense for a bike to be equipped with a rim brake on the front, and a disc brake on the rear? This way, one could avoid the need for overly stiff fork blades. Also, with such a setup, one could rely more heavily on the rear brake in wet weather or on long downhills (to avoid over-heating of the front rim), while relying more heavily on the front brake for modulation. Aesthetically however, a bike with this “mixed” setup might look odd, especially if it necessitated mismatched brake levers or brifters.

    January 10, 2017 at 7:44 pm
    • Jan Heine, Editor, Bicycle Quarterly

      Some old French camping bikes were set up that way, only they used a drum in the rear. The drum served for keeping the speed down on gravel descents, the canti at the front (centerpulls had not yet been invented) was for real braking when speed had to be shed quickly. There is a beautiful René Herse with that setup in our book The Golden Age of Handbuilt Bicycles. It’s one of my favorite bikes in the book, so I don’t think it’s aesthetically challenged!
      If you use mechanical discs and a centerpull on the front, you can use the same brake levers. In fact, that is one of the reasons we sell our Compass centerpulls as individual brakes, not pairs.

      January 10, 2017 at 7:53 pm
    • Peter

      Thorn Cycles in the UK sells bikes set up like this.

      January 10, 2017 at 11:12 pm
  • Pete

    Hi Jan, any thoughts about disc brakes being a disadvantage when used with quick release wheels, for safey reasons?

    January 10, 2017 at 8:07 pm
    • Jan Heine, Editor, Bicycle Quarterly

      That can be a serious problem. Lawyer lips, as annoying as they are, must be used when using disc brakes. I once rode a bike without, and the wheel had not been installed very tightly. I braked hard, and afterward, the wheel was crooked in the fork… A little more braking, and it would have come out. Ah, the risks of being a bike tester…
      Fortunately, thru axles seem to have solved that problem.

      January 10, 2017 at 8:10 pm
      • Andy Stow

        Why oh why haven’t they moved the caliper to the front of the fork? It seems so obvious. Institutional inertia, or is there a technical issue which eludes me?

        January 12, 2017 at 6:36 am
    • Chris V.

      I believe that technology related to thru axles is being worked on to help quicken\speed up wheel changes in racing applications. Thru axles really help with wheel tweak and disc brakes. With that said, I also subscribe to buying aftermarket quick releases that will allow a higher tightening force on the hub, and in my experience that has done away with wheel twisting.

      January 11, 2017 at 7:38 am
      • Tom_Anhalt

        IME, using a fork with forward facing dropout slots also makes for a secure wheel connection (since the disc braking forces aren’t aligned with the dropout slot). I’m using a Salsa Vaya fork on my “all-road”.

        January 11, 2017 at 1:23 pm
  • Anon

    Has anyone used U brakes like C.S. Hirose in BQ no. 53? I’d love to try them on one or more of my rigid steel mtbs. What are the best U brakes to use iyo? Too bad Compass doesn’t make them…yet.

    January 10, 2017 at 8:46 pm
    • Jan Heine, Editor, Bicycle Quarterly

      For those who don’t have Bicycle Quarterly 53, C. S. Hirose uses old mountain bike U-brakes as centerpulls. (They are the same design, just much beefed-up.) Haven’t tried them, but Hirose wouldn’t use them if they didn’t offer a little more stopping power than even the Mafac Raid (and Compass centerpulls that are modeled on them). Might be fun to try at some point!

      January 10, 2017 at 9:02 pm
    • Conrad

      That looks like an ideal brake for an enduro allroad bike. I wish I could try them.

      January 11, 2017 at 8:51 am
    • jasonmiles31

      I am using these U Brakes on my Enduro all road.
      I had trouble with too short brake reach and fender clearance, but that could be a bike specific problem as I was replacing roller cam brakes.
      As far as the brakes themselves the the straddle cable is much too long and the pads are too grabby. Switching those out and the brake is performing well excepts for some squealing.

      January 11, 2017 at 11:31 am
      • Conrad

        Do they mount on normal cantilever posts (like for V brakes) or do you need specially placed posts for them?

        January 12, 2017 at 10:42 am
  • Chris

    So if can’t it’s twist flexible fork blades, disc brakes require stiff fork blades, and the compass centerpulls max out at 42mm tires + fenders, what is your opinion of the optimal brake for a bike running rat trap pass tires?

    January 11, 2017 at 6:28 am
    • Jan Heine, Editor, Bicycle Quarterly

      Good question. If the bike sees mostly use on gravel, I’d use cantis, because you can’t brake that hard on loose surfaces anyhow. For road use – discs?

      January 11, 2017 at 9:06 am
    • Jeff

      Chris, I run full length XT parallel vees on the front with with a Problem solvers adaptor for drop-bar usage. They are very progressive, strong and easily modulated. I have a long arm canti on the back which is pretty much for decoration. The Rat-Trap Pass tires are great all rounders which have increased my descending confidence levels a ton on the road.

      January 11, 2017 at 11:24 am
  • Owen

    Chris, I’ll second Jeff’s setup as described above–I’m running an Avid SD-7 v-brake with Problem Solvers Travel Agent on the front and a Tektro CR-710 canti rear, Kool-Stop Salmon Pads on both. Levers are standard Shimano BL-R400 as I prefer bar-con shifters to Ergo for use with drop bars. The frame is a steel touring bike I’ve set up as an all-rounder, on pavement I have all the braking power + modulation I could want. Off-road, running 35mm cross tires on steep descents (which I probably shouldn’t), I can lock the wheels easily but as Jan pointed out off-road braking is also related to tire size and grip. I could probably improve braking and control by running one of the newer 45c monster cross tires, but I’m hesitant as I ride ~50% on pavement. Both brakes work fine, though the Tektro squeals a bit, the set up is economical, easy to set up and brake pads for both last a long time.
    Jan, I would be very curious to hear more about Hirose’s U-Brake set up and hope for a BQ test. It seems like this was a good design that was basically forgotten–witness the cult following for the WTB/Cunningham Roller Cam and Lever Link brakes.

    January 11, 2017 at 12:32 pm
  • Anon

    Getting the u brakes set up correctly will take some practice especially since they used to be placed under the chain stays! I’d love to learn more about how Mr Hirose does it- might be a good blog post or BQ article…. What if there was a u brake that looks and functions like a classic center pull caliper?

    January 11, 2017 at 3:23 pm
  • Anon

    Jan- have you had the chance to test the stopping power of the u brakes on one of Mister Hirose’s tandems?

    January 11, 2017 at 3:51 pm
  • George Chomacki

    Folks, I’ve just tried to find a 26-inch rim on the WWW & could only find ones that were disc- compatible. I didn’t spend a huge amount of time searching but did find a site that seemed to carry quite a few 26-inch rims. So if the others, that is the rim-brake ones, are kinda rare in 26-inch, wouldn’t it be reasonable to just get what’s most available & go the disc-brake route if the Compass Rat Trap Pass set-up is what’s desired? Or just go the 650Bx42 route & use the Compass Centre-Pulls per Jan’s advice? I’m starting to get a head-ache. All I want is a bicycle that I could jump onto & go wherever I wanted short of mountain-biking terrain, without having to think about constant adjustments (or pad replacing), squealing noises when stopping, rubbing pads….the issues that I’m sure would drive me nuts. I’ve never worn out a rim in my life, but obviously that’s because I didn’t cycle enough. I’ve only scared myself once braking in the wet using Gran Compe centre-pulls, although “surprised” might be more of what I felt, so am not convinced that improved braking is required. I’m done with work this summer so let’s suppose I go cyclo & leave the canoe on the rack & live on the fancy-custom-made-way-more-than-$2000 bike. How many sets of rims am I going to go through if the rim-brake (650Bx42) is the choice? Two? Three?
    Here’s the other pressing question in my mind though. Is the 26×2.3 tire size going to be any great advantage over the 650Bx42 size (I’m thinking it might be)? This is what I think I’m going to do. If I go with the 650B wheel on my new bicycle I’ll have them make it to fit the Compass centre-pulls. If I go with the 26″ wheel in order to fit the fatter tires I’m going to consider that discs are the default choice & just stomach it.
    A great discussion, folks. Stay well.

    January 11, 2017 at 8:18 pm
    • Jan Heine, Editor, Bicycle Quarterly

      Last I checked, the Velocity A23 was still available in 26″. But you are right, there is a need for a rim-brake 26″ rim.

      January 11, 2017 at 11:02 pm
      • Conrad

        I wish you would collaborate with velocity to make a rim optimized for compass tires, including an asymmetric rear. The A23 is okay but being designed for tubeless, a pain in the neck to mount most tires on. A tubeless cross section negatively affects the structural integrity of the wheel, too.

        January 12, 2017 at 9:20 am
      • Christoph

        Actually, in addition to the A23, Velocity is still making/selling several other rim-brake compatible 26″ rims. I just ordered a set of their 26″ Aeroheat rims which are a bit wider (and possibly stronger) than the A23’s.
        Ryde offers numerous suitable rims, too; most of them can only be had in black, though, and they tend to be rather heavy. Even big manufacturers like Mavic and DT Swiss still make 26″ rims for rim-brakes, but once again, they are only available in black.

        January 12, 2017 at 9:57 am
      • John

        This might be a possible 26″ rim option: http://www.ryde.nl/andra-30

        January 14, 2017 at 12:48 pm
  • Jeff

    Velocity have quite a few 26 inch rims with rim braking surfaces I think. Some pretty robust ones.

    January 12, 2017 at 1:05 am
    • Conrad

      Yes, they do. The aeroheat has worked really well for me.

      January 12, 2017 at 9:13 am
  • Willem

    Plenty of rim brake rims for 26 inch bikes here in the Netherlands, e.g. by Ryde (once called Alesa or Exal). The Sp19, also called Sputnik, is the favourite heavy duty touring rim. It will last many miles (20000?).
    I don’t have a 650b bike with 42 mm tyres, but I do have a 26 inch loaded tourer with Rat Trap Pass tyres, and I love the tyre for loaded touring in most of Europe. Obviously, for an expedition tour in the third world I would take something sturdier. As I said earlier, my Magura hydraulic rim brakes are perfect for this application.
    In my book a 650B bike with 42 mm tyres is primarily a tarmac bike, but usable for the occasional gravel roads. Before converting to the Rat Trap Pass I used the Compass 26×1.75, and there were quite a few moments on two recent camping tours in Germany and Central Europe that I was longing for the then not yet avaible wider Rat Trap Pass.

    January 12, 2017 at 2:43 am
    • Alex

      Exal, a German company, still makes excellent rims under its name, & Ryde used to be Rigida (which previously had bought Alesa & Weinmann). So even more choices of 559 etc rims than you thought, Willem! Although I’m a fan of rim brakes, as I’ve never had trouble stopping my bicycle (I’m only 50ish, so maybe I just haven’t ridden enough 😉 ), the wide, disc-only rims are obviously where the development is focused & they’re sorely tempting. Biggest argument against discs for me is the fork: I like my forks comfortable & flexible.
      I do appreciate two comments above somewhere: rim brakes are, mechanically, massive disc brakes, & the appeal of disc brakes is perhaps due in a large part to the hydraulic-assisted ergonomic benefits they are most often associated with.

      January 12, 2017 at 9:44 am
  • loursblanc

    I had the opportunity to use most of the common brake systems. All have their character. I finally decided that knowing it helps more than continuously looking for something else.
    The one brake I really had decided I wanted to hate for its awkward look, mounting-, and quick release- system turned out to be the best overall experience for me (in its specific use case): The basic Magura HS11 hydraulic rim brake. If there were a more elegant mounting system and road levers still available I would consider it for randonneuring.
    Jan you made a critical remark about Dia-Compe center pulls. Could you be more specific? I considered the Dia Compe Gran Compe GC450 for a vintage frame and thought it looks nice.

    January 13, 2017 at 12:32 am
    • Jan Heine, Editor, Bicycle Quarterly

      Jan you made a critical remark about Dia-Compe center pulls. Could you be more specific?

      During the design of the Compass brakes, we analyzed many centerpull brakes to determine what makes a good design.
      The lower arms on the Dia-Compe model for wide tires are much longer than they are on the Mafac/Compass brakes, and the upper arms much shorter. That greatly reduces the braking power. Also, the GC450 has an arm shape that results in much more flex than necessary.
      Really, the Mafac Raid stood heads and shoulders above the rest – even compared to other Mafac models. That is why we based our design on the Raid – it’s almost impossible to improve upon.

      January 13, 2017 at 7:09 am
  • Willem

    It is complex: Ryde is the current brand name for Rigida, Alesa and Exal. And they have plenty of 559 rims for rim brakes in various weights, also in silver. They now also do a nice 584 rim in silver.
    See here: http://www.ryde.nl/rims-search—8194-136-

    January 13, 2017 at 3:02 am

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