Revisiting Cable-Actuated Disc Brakes

Avid BB5 on Civia Bryant

A little over a year ago I wrote one of our “Stuff We Like” articles about cable-actuated (aka “mechanical”) disc brakes. In a nutshell, I said that while I prefer the aesthetics of traditional brakes, I enjoy mechanical discs for their performance advantages. Here’s an excerpt:

“While I prefer the aesthetics of a delicate, high profile cantilever or a classic, dual-pivot caliper, I have to admit that nothing quite beats the overall performance of a high-quality, cable-actuated disc brake (also known as “mechanical” disc brakes). Drum/roller brakes are heavy and generally provide only mediocre braking performance, and most every other type of performance brake uses the rim wall for a braking surface, a fact that guarantees your rims will be toast long before your hubs go. Rim brakes can sometimes be poor performers in wet conditions, they make an awful mess in the rain, and the caliper variety rarely provide sufficient clearance for robust tires and fenders.”

Now that I’ve been running mechanical discs on my daily commuter for about a month, I thought I’d point out again how much I like these brakes. They’re powerful, easy to set-up, weather-resistant, and clean as a whistle in the wet. Following are a few of their advantages and disadvantages:

Advantages

  • Powerful
  • Easy to set-up
  • Rim-friendly
  • Not affected by out-of-true rims or broken spokes
  • Weather-resistant performance
  • Boat loads of tire/fender clearance

Disadvantages

  • Require a beefy fork
  • Front wheel must be dished
  • Require disc-specific frame mounts
  • Rotors can be fragile
  • Can interfere with rack and fender mounts

Hydraulic discs provide even better performance than mechanical discs due to the elimination of cable drag and housing compression. From a pure performance standpoint, they really can’t be beat. That said, working on hydraulic discs can be a challenge. A relatively simple thing like swapping out handlebars can get fairly involved when you’re looking at changing the length of hydraulic lines and bleeding brake systems. For me, the simplicity of cable-actuated discs outweighs the performance advantage of hydraulic discs.

I’m running Avid BB5′s on both my grocery getter and commuter (Civia Loring, Civia Bryant). While I prefer the BB7 caliper for its ease of set-up (the BB5 only has one pad adjustment knob, whereas the BB7 has two; one for each pad), the performance of these brakes has been flawless and on par with my best rim brakes. Now that I’ve gotten the hang of it, setting-up these brakes is at least as easy as setting-up calipers and V-brakes, and I find them easier to set-up than cantilevers.

Mechanical discs aren’t necessarily for everyone, and they’re certainly not a good aesthetic match for old school bikes, but they offer a number of advantages and make a lot of sense on modern commuters and cargo haulers.

35 Responses to “Revisiting Cable-Actuated Disc Brakes”

  • dweendaddy says:

    You say:
    “For me, the simplicity of cable-actuated discs outweighs the performance advantage of hydraulic discs.”
    I say:
    “For me, the simplicity (and cost and swap-ability) of calipers outweighs the performance advantage of discs.”

  • Dolan Halbrook says:

    One advantage that you hinted at but didn’t mention outright is that the pads last a really, really long time. I commute daily year round in Portland and change the pads once a year, sometimes even longer.

    However, I can’t seem to get mine not to squeal at least a little bit. It may be because neither rotor of mine is stock, but it’s still annoying. That said, I’ll take noisy and powerful over silent and useless any day of the week.

  • Dolan Halbrook says:

    Oh, and for disadvantages you left off \heavy\, and \requires disc specific hubs\.

  • Daniel M says:

    This seems like a very balanced summary. I would make some slight adjustments to the “disadvantages” category:

    -Require a beefy fork and rear triangle

    -Front wheel must be dished and strengthened to cope with braking torque

    Pretty minor nitpicks, really. I have yet to be bitten by the disc brake bug, but if it ever strikes, I will most certainly choose cable-actuated over hydraulic for reasons of simplicity and reliability. Until then, I will soldier on with quality V-brakes on all of my bikes: 700C drop bar light touring bike, 26″ flat bar IGH-equipped heavy touring bike, and 20″ folder. For me if it ain’t broke, don’t fix it.

  • Bob Bryant says:

    I’m thinking of outfitting a new cargo / trailer tow bike with a cable disc. However, for everyday use, I prefer calipers. Nothing beats the simplicity, affordability and ease of maintenance. I love them even more every time I work on cantis, V-s or discs.

  • Dolan Halbrook says:

    @Daneil M

    I know it’s somewhat off topic, but I’ve found that V-Brakes with Kool-Stop Tectonic pads come very, very close to the power of my mechanical discs, wet or dry. They’re cartridge shoes as well, so replacing them is pretty simple. That said, you’ll definitely be replacing them more often than the disc pads.

  • Alan says:

    Hi Dolan,

    “Oh, and for disadvantages you left off \heavy\, and \requires disc specific hubs\.”

    Right; the brakes themselves are heavier, and the fork and wheels need to be beefed up as well. I always ride beefy wheels anyway, so that part of the equation is moot in my case.

    I’m curious to know more about your Rawland. There are only a small number of bikes with curved forks and disc brakes. Do you notice any flex in the fork associated with braking? I recall you mentioned those forks as being vertically compliant and providing shock absorption; I’m wondering how those characteristics work with the disc brake.

    Thanks in advance..

    Alan

  • Alan says:

    @Dolan

    “I know it’s somewhat off topic, but I’ve found that V-Brakes with Kool-Stop Tectonic pads come very, very close to the power of my mechanical discs, wet or dry”

    The same is true of my Paul Neo-Retro cantis with salmon Kool-Stops…

  • John Ferguson says:

    I’ve been using the cable actuated BB7′s on my regular commuter for a couple of years and I’ve come to a few conclusions:

    1. They work much better in the wet – in fact wet weather seems to bring out the best in these brakes. They don’t squeal when it’s wet and the braking force is very progressive.

    2. The pad compound you choose to use has a pretty big impact on the power and modulation. I believe the Avid BB7 and BB5 come stock with the ‘organic’ compound pads. When I changed to sintered I saw a big increase in braking performance. As a trade off, they’ll wear down the discs more quickly.

    3. If you use them with road levers (as I do), they require much more fiddling to keep the pads from rubbing the discs because you have to set them up tight to get them to engage fully. I also found that the Avid discs are rarely completely straight so there’s a bit of truing involved on the discs themselves if you want to minimize disc rub.

    4. I don’t find that braking power in dry conditions is much different than a good set of cantilever or linear pull brakes. Better stopping power than calipers, though.

    The real benefits to these brakes are mostly in damp or wet conditions. If you ride in mostly dry conditions on the road, probably no need to consider a change from rim brakes.

  • Dolan Halbrook says:

    @Alan

    I don’t notice any huge fork flex when hitting the front brakes hard, or at least it’s certainly not enough to cause my front braking power to be compromised. The forks are quite compliant forks and I can see them flexing forward and aft under normal riding conditions. I’ll have a closer look on the way home tonight and report my findings.

  • Dolan Halbrook says:

    @Alan

    Makes sense that the Tectonics are similar to your Salmon pads in this way as part of the pad is indeed the salmon compound (at least on mine): http://www.koolstop.com/english/tectonic.html

  • Don says:

    Never having used discs, I look at your photo and think, “Wow! That’s a lot of stuff in a small space. With regard to rack interference, people sometime broach the idea of a disc upfront and a canti or even drum brake in back. What do folks think about that set-up? It certainly seems like it would open some bikes to a conversion, albeit with a new fork and front wheel. but if you’re getting one anyway, worth a try.

    Also, as a somewhat heavier rider, I often wonder if there is a point at which discs begin to outperform rim brakes more markedly.

  • Dolan Halbrook says:

    @Don

    As a heavier rider, you might best appreciate how much longer your rims last.

    @Alan

    I had a good look and quite a few tests on the way home and there is definitely aftward fork flex when I hit the front brake, but not enough for me to notice any real diminished stopping performance, and certainly not enough to offset the improved ride for the 97% of the time I’m not using the brakes.

  • Alan says:

    Hi Bob,

    Dual-pivot sidepulls are certainly easy to work on. Unfortunately, short reach models typically only work with tires up to approximately 28mm – beyond that and you can’t get the wheel out from between the brake pads. And mounting fenders, even with the so-called “mid-reach” Shimanos, can be a chore.

    I’m curious about the various long reach sidepulls from Silver and Tektro that Rivendell sells. My experience with long reach calipers has not been stellar (too much flex, too little braking power), but I have to assume these are good brakes. I’ll have to get a ride on my friend’s AHH to try them out one of these days.

    Alan

  • Dolan Halbrook says:

    @Alan

    FWIW, my best guesstimate there was about 1cm of rearward flex on really heavy braking.

  • Alan says:

    Hi John,

    “If you use them with road levers (as I do), they require much more fiddling to keep the pads from rubbing the discs because you have to set them up tight to get them to engage fully.”

    I’m assuming you’re using the “road” caliper as pictured above?

    I’ve found the Avid “MTB” calipers with MTB levers easier to set-up than the “road” calipers with road levers. Like you describe, I have to run the pads tight for full engagement.

    Alan

  • Martin says:

    I rode my Bryant Belt Alfine every work day this winter.
    The disc brakes worked perfectly. Snow, slush, rain, drivers on phones, no problem.
    Durability and poor conditions performance is worth any weight penalty.
    The fork flexes under braking, but only noticeable visually.
    PS Coupled 1996 Salsa La Cruz for sale. Roots.

  • Bob Bryant says:

    Alan, Right, sidepulls means skinnier tires. My rainy commuter Astra Tour de France 1×5 has 27″ x 1-1/4″ tires under vintage 35 year old French metal fenders (not much choice in tire size). The front brake is a Weinmann center pull, the rear a Weinmann sidepull. Brake handles are vintage Weinmann tourist levers. I’ve had decent luck with Tektro long reach and dual pivots on road bikes. If I wasn’t using calipers, I’d want Shimano rollers or a coaster/drum combo.

  • Alan says:

    Hi Dolan,

    Thanks for the information. I can’t imagine the flex affects braking performance to any significant degree and it seems like a fair trade-off for the added comfort.

    It’s so unusual to see a curved fork with a disc brake. Have you discussed the fork with Sean? I’d be curious to know more about the design process that went into that fork.

    Alan

  • Doug P says:

    I have BB-7 discs on my mountain bike. The stopping power is impressive, and as John Ferguson said, rain seems to bring out the best in these brakes. Off the pavement in wet, gritty, hilly conditions, rim brake pads can wear out in one ride! I have dual-pivot calipers on my road bike, and they work well too, although not so much in wet conditions. But my favorite brakes are my TRP CX-9 mini V-brakes. I have them on two ‘cross bikes, and they are far and away the best bicycle brake I’ve used. I will never use cantilevers again! Once I got used to the light touch needed, I was sold. The pads are excellent as well, so although the brakes are pricey, I won’t be tempted to pay for aftermarket pads. I am a fan of V-brakes in general. They are a light and simple design that offers awesome stopping power for the price. The V-brakes on my tandem stop better than any canti ever did, and for a price of about $10 (or less!) per wheel.

  • Sharper says:

    Given the discussion so far, I’m wondering what sort of riding I’m not doing that the stock rims and caliper pads that came on my 30 year old commuter have seen me through 3,000 miles and can still stop faster than my momentum can.

  • Lee Trampleasure says:

    A couple thoughts:

    I’ve ridden for over 40 years, and never with disk brakes, but I’ve never been in a situation where I needed more stopping power than I had with caliper brakes (and I’ve ridden on tour with me/bike/cargo totaling over 300 pounds). So, while there may be a rare emergency when one would need more braking power than a good set of caliper brakes (I just upgraded to Paul brakes and Koolstop pads that I love), I think good defensive riding (both reasonable speed and watching in front of you) will remove the need for any increased stopping power.

    I’d also much rather invest my money in a dynamo hub (although I did check and you can get dynamo hubs that will also run a disc for brakes).

    In the end, to each their own, but I’m not convinces of the *need* for any additional stopping power.

  • Phil says:

    I’ll keep going with my Arch Rival 50s on the Mundo. I have to change the pads every three months, that is probably due to the height and gradient ( 180 metres over 2.2km, gradients of 1 in 8 ) I have to descend every day from work in all weather. I adapted Aztec cartridge pads with washers to avoid paying ridiculous money for Avid Rim Wranglers ( good, but way too expensive ). My commuter converted MTB has Shimano cable disc brakes, but when it’s finished ( still waiting for a Sturmey Archer 8 speed hub ) I’m switching to hydraulic discs, as the aluminium frame doesn’t have canti/v-brake mounts.

  • Pete says:

    @Alan-
    I put Tektro 556 long-reach sidepulls on my Sam (I have a non-canti version) when I first built it up. I was really surprised at how much they flex. I hadn’t ridden a caliper bike in 20 years, but I never recall that much flex. Those old calipers were probably short-reach, though. Even if I had the Tektros set up very close to the rim, I could pull the brake lever all the way to the bar while the caliper just kept flexing.
    I switched to Dia-Compe 750 centerpulls, thinking they might be better. They are, a bit, but I’m still not thrilled with stopping power, even with Kool-stop Salmon’s. I can’t imagine the Mafacs and vintage Diacompes that everyone fawns over are much better.
    The Paul Racers might be pretty good – if you just compare the size of the arms below the pivots you see there is 2 or 3 times as much material on the Pauls as the others. Above the pivots they get pretty skinny, though.
    Guess I’ll have spend big to get better brake performance on that bike…

    @Don – The disc front/ V-brake rear is done on cargo bikes sometimes. The only reason you might not like it is that the feel of the brakes would be so different front to rear, and the levers themselves won’t match, so they might have different amounts of travel, etc.

  • Micheal Blue says:

    @ Sharper, I agree with you. I rode my Dahon throughout the whole winter and also in plenty of rain and haven’t experienced any braking problems. It has just cheap Shimano V-brakes with basic brake pads. Maybe I’d have to race or at least ride aggressively to notice a difference.

  • John Lane says:

    I recently started riding a new Kona Honky Inc. commuter with BB7′s. Before, I’d had nervous experiences with performance road bikes in heavy rain; the rims had to heat up from friction before slowing started. After a friend laid down the Kona on a test ride, I had to adjust its brake mountings. I found a PDF file for this at Sram. In fact, every time I take the wheel off, I have to adjust the pads. However, I’m getting much better at this over time. The brakes are set up tighter than when I took delivery, without rubbing. The dust squeak is similar to automobiles. The overall feel is robust.

    Note: I sometimes find myself on steep hills (did they just pour the asphalt down a slope?). I feel confident with the discs. One issue that drove me toward mechanical was potential vandalism. If there is a problem with the cable, it will be immediate, maybe not so with hydraulics.

  • Alan says:

    @Pete

    Thanks for the feedback on the Tektros. Your experience mirrors my past experiences with long reach calipers and I’m disappointed to hear those brakes didn’t work better for you. It sounds as if Paul’s are probably the fix, though as you said, they’re pricey.

    Alan

  • Tyler says:

    I have been riding with BB5s on my commuter everyday since early 2009. Before that I had a bike with linear pull brakes that I used for over ten years. I absolutely love my BB5s. They work very well in all sorts of weather (and I live in the rainy Pacific Northwest), they require very little maintenance and tinkering, and they are oh so clean and quiet. I would not consider a commuter bike without discs.

  • Reed says:

    I used BB7s on a 29er last winter (Wisconsin) which greatly reduces the longevity of the brake pads – salt and other materials to melt snow also deteriorate the brake pad surface. In addition, as you might expect in high-salt areas, the rotors began to rust around the edges. So, while care is reduced compared to v-brakes, there is still maintenance required to ensure a clean contact area and reliable braking. Oh, and they sure do “honk” when cold, wet.

  • John Ferguson says:

    @Alan

    You’re correct – I’m using the BB-7 road caliper with road levers. I need to set them up tight, but once things are adjusted properly they work pretty darn well. I’ll put the same brakes on an xtracycle build I’m doing later this spring, so I’ll test out the mountain calipers/levers at that point.

    @Don, I’m using the disc up front and some older shimano cantilever brakes on the rear of my Redline ‘cross bike. One advantage of that is easier rack installation, and I didn’t have to build myself a new rear wheel. The brake feel is a bit different on the two systems but you get used to it. The modulation at the lever seems to be greater for the disc brake than it is for the rim brake, so I have to be a little careful that I don’t grab them both with the same speed and force. The rear will lock up much faster and easier than the front, and the only time this has been an issue for me is in panic stops (which I try to avoid..) I’ve slid the rear tire around a bit as a result, and my thought is that I wouldn’t do it as much if I had disc brakes on both wheels.

  • Jed says:

    I like having the same sized tires and drivetrains on family’s bikes for maintenance’s sake. If I need to borrow my wife’s wheel for a day, I can still get to work if she’s doesn’t need it. Thus, if I were tempted to upgrade to disks, I’d seriously be interested in upgrading like three bikes all at once. I don’t have the need for that yet. However, if I were doing lots of downhill, like fire-trails or other bike camping adventures, esp w/ kids on the back of my XC, I’d certainly consider upgrading the XC to disks first.

  • john bokman says:

    This is a great topic. I have recently been considering setting up a commuter bike and have spent considerable time trying to decide which type of brake to install and spec: Mechanical Disc or V. Having said this, I have owned both; each has its merits.

    I live in the Pacific NW where it is often wet 8 months a year. Disc brakes are nice for this climate because they require less regular maintenance than a V brake to work well. At least for me, this is at the very crux of the issue. This is the disc brake’s great advantage: they are cleaner and keep the bike cleaner. Both work well in all conditions when maintained.

    Here is the compromise: Are you willing to do a little regular maintenance to get great perormance out of your V brake system? If not, will you accept it when your brakes aren’t working as well as they should? (I am afraid to say, more often than not, I fall in the latter camp, and yes, I do accept this fate.)

    In my experience, “regular maintenance” in these parts means once a week, depending on conditions. But maintenance is usually no more difficult than cleaning the rim and brake pads. 5 minutes of work, at most? Every so often, yes, a new set of pads is warranted, but they are not difficult to install, especially if one uses the sliders. They aren’t all that pricey, and it always feels great to be using a new set.

    I have decided to go with the V brakes. I will try to do a better job of regular maintenance!

  • Ira Kinro says:

    I’m going to chime in for hydraulic discs. The seals and hoses last quite a while. They’re pretty low maintenance. I don’t change handlebars on my bikes. Hmmm. Funny, I can’t remember *ever* changing the type of handlebar on any of my bikes. When one needed replaced once, I just bought the exact same one. Also, as has been mentioned earlier, the weight of the rider makes a big difference. As the 300 Pound Gorilla, I’ll just say that I feel better with hydraulic discs.

    I have had problems with rim brakes not working as well in the wet. Worse, I’ve had problems with rim brakes not working in the heat. Going down a steep hill on a hot day, red light at the bottom, the rim heated enough to blow off the tire. woops.

    I have had problems with drum brakes not working as well in the anything. haha Seriously though, they’re fine for casual riding and commuting – as long as you don’t have to stop in a hurry. I actually walk down steep hills when I’m using drum brakes.

    So, that leaves me with discs. I pick hydraulic over cable actuated. I like the power, and the mechanical side doesn’t bother me.

    PS who decided that cable actuated were mechanical? hydraulics are definitely mechanical. :)

  • voyage says:

    I wonder whether people even know how to brake given all the exogenous (situational) variables; regardless of brake type, brake type mix, business card spacing and other esoterica.

  • Brian C says:

    I have hydraulic discs on my winter bike ( A rocky mountain Whistler), and definitely have enjoyed their stopping power in all weather. I do think that an internal hub and belt drive would be the next step toward the ultimate all-weather bike…

    I used my wife’s soma buena vista for part of the winter – I enjoyed the low maintenance on her internal hub, but I must admit I missed my disc brakes (her drum brakes just are not as good). I have not seen any main-stream mixte bikes with disc brakes – anything out there anyone knows about?

 
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