Disc brakes for a commuting bike?

December 31, 2008 7:56 AM

What kind of disc brakes and brake levers (if necessary) should I get for my new commuting bike?

I'm going to be building a new commuting bike using a Soma Fabrications Double Cross DC frameset. I've never had a bike with disc brakes before, so could use some advice.

What disc brakes should I look at? Think good quality but not wildly expensive. I already have regular wire-pull-type brake levers but I'm not sure that they can be used with discs, so if you have lever recommendations that'd be helpful too.

I'd also appreciate any thoughts on wired versus hydraulic disc brakes... a few years ago, when I was paying more attention to the market, that was the major distinction between cheaper and more expensive discs, though I'm not sure how things have changed in the interim.

posted by Captain Rayford Steele, Tribulation Force to health & fitness (14 answers total)

I used Avid BB7 Road on my similar bike. I am very happy with them now that they are broken in.
posted by procrastination at 8:17 AM on December 31, 2008

Unless your commute is downhill on a steep offroad trail you probably don't need them. They are extra expense and weight compared to traditional brakes.
posted by BobbyDigital at 8:33 AM on December 31, 2008

I can't comment on compatibility with levers or forks (because I don't know a lot), but I have Avid BB-5 brakes on my commuter and they are excellent - great stopping power and easy to adjust. Highly recommended. (Not sure where you are in the world, link is to a UK retailer; they're around £40 including rotors)

Regarding cable versus hydraulic brakes, I think hydraulic gives greater power and needs less regular maintenance, but hydraulics are more complicated when they do need maintenance (bleeding etc), and you have to be careful with brake fluid, I believe it's nasty stuff.

Finally, if anyone tries to tell you you don't "need" discs if you don't go off road, ignore them - compared to the v-brakes on my previous bike, discs are a massive improvement, especially in the rain. I guess they make the wheel heavier so if you're the type that looks to shave every spare gram of weight off then maybe they're not the first choice but I wouldn't go back to rim brakes if I could avoid it.
posted by Dali Atomicus at 8:33 AM on December 31, 2008

I vote for BB-7's as well.
Superb brakes.
posted by whoda at 8:39 AM on December 31, 2008

Oops, my last paragraph wasn't intended as a pop at you personally BobbyDigital. Accursed simultaneous posting.

You have a good point as regards extra cost; the initial outlay is greater and the pads are a little more expensive. However the performance in the rain and wet for me outweighs any downsides - I commute in all weathers in heavy traffic and even well maintained rim brakes don't cut the mustard compared to discs when the weather is rubbish.
posted by Dali Atomicus at 8:40 AM on December 31, 2008

Bobby, you ever ride in the rain on surface streets? It's a mofo. I've not ridden more than a test ride on disk brakes, but if they're any improvement at all over rim brakes, I'll put them on my next bike in a heartbeat. I mostly take empty streets where possible, and still have had any number of run-ins where slightly slower reflexes would have meant some serious hurt (and one accident that I got on the brakes quickly, but just couldn't stop in time..bye tooth). And that's dry - when it's raining, my god, you might as well stop Fred Flintstone style or throw yourself at the nearest light post.
posted by notsnot at 8:57 AM on December 31, 2008

I have a 7 mile bike commute that is all city (DC) with a fair amount of hills. I go pretty fast, and I have a very low opinion of both the drivers and roads in my fair city yet I never have had a problem with my brakes. If I cant stop in time its because of my tires (Armadillo, but it is a track bike so skinny and fairly slick) and not my brakes.

I just personally feel that disc brakes are generally not worth the extra expense for most of the bikes they are put on. I dont even have them on my mountain bike, but that is more because I do more single track than downhill and I am also cheap.
posted by BobbyDigital at 9:39 AM on December 31, 2008

I'm with Bobby Digital. I used to bike commute for years and never needed disc brakes. Disc brakes are for racing bikes and poseurs.
posted by Ironmouth at 9:51 AM on December 31, 2008

All I am going to say is that I have never had a problem stopping the wheel from rotating with old fashioned brakes, but on occasion I have not been able to stop the forward momentum even with the wheels stopped, disc brakes wouldnt have made a difference. If you want my advice it is to stick with regular brakes and get nicer tires.
posted by BobbyDigital at 10:18 AM on December 31, 2008

I've done lots of riding in all kinds of weather on several bikes.

Steel rims (common on cheap bikes) are dangerously horrible for stopping in the rain. But with aluminum rims (found on decent and better bikes) I've never had the brakes be a problem in the rain or slush - good modulation with ability to lock up either wheel.

Traction between the tire and the pavement will be limiting in the wet, and disc brakes will do nothing to help there. I recently built an all-weather commuter/city bike (with an IRO Rob Roy frame) using cheap cantilevers from Nashbar and they're totally fine. If I had your frame I would do the same using the canti bosses. But if you're set on discs, I've heard good things about Avid.
posted by exogenous at 10:38 AM on December 31, 2008

BobbyDigital & Ironmouth:

The question wasn't "Do I need disc breaks?" It was, "What disc breaks combine quality and value?"

The OP isn't YOU. Just because YOU can't fathom why the OP would want such breaks, doesn't mean they are completely without merit.

In other words, if you're unwilling to answer the question, please STFU.

There are numerous reasons that the market for mid to high end commuter bikes is moving toward disc brakes. Notably, disc brakes work better in wet and icy conditions, and by putting all the wear on the disc this avoids the frequently brake pad replacements. Further, disc brakes are easier to setup, and to keep tuned, and ultimately save wear from your rim too. They are simply a better system for commuters who find themselves ridding in wet and grimy conditions.

Rayford, as other more serious responders have noted, the Avid BB-5, and BB-7 seem to be the norm. Bikes Direct outfit their entry level disc-equipped cyclecross bikes with the BB-5.

As for lever compatibility, they will work with any non-V-break lever, that is basically any drop lever, etc. V-breaks require more cable pull (or is it less, I always forget) so if you have those on your bike now, you'll need something different for the disc breaks.

Good luck with your ride, it sounds awesome.
posted by wfrgms at 11:03 AM on December 31, 2008

Rim brakes wear out rims, which is dangerous, and rebuilding wheels with new rims isn't exactly cheap, so the upfront cost of disc brakes is offset to some degree by the reduced maintenance cost.

I've ridden mountain bikes in snow and slush a little, and I've ridden a heavy duty touring bike with cantilever brakes and nice wide grippy tires in a lot of rain and crud. Sure, it was possible to lock up the wheels on both when the rims were wet or mucked up, but it took a lot more brake lever travel and force, not to mention a few extra revolutions of the wheel, and it wore a lot of aluminum off my rims.
posted by Good Brain at 11:55 AM on December 31, 2008

I commute on a bicycle every day throughout the entire year. I wish I had disc breaks on my bike. Why? Because in winter, salt and road grit mix with melting snow and create a tremendously effective sandpaper that wears down your breaks and wheel rims. Winter eats break pads. And ever had a wheel rim suddenly collapse while cycling? Not fun. Disc breaks avoid some of the problems of rim breaks:

- No wear and tear on the rim of your wheel.
- Not affected by weather to the same degree as rim breaks.

If you commute in the winter it's probably a good idea. If you're just a fair weather commuter, I guess there less benefit, but if it's not going to break the bank I'd say go for it. It's a commuter bike; weight is probably not your primary concern. I've got both a front and rear rack on mine; it's a freaking tank. The difference in weight between rim breaks and disc breaks is probably not going to be noticeable. Quoting from http://mountainbike.about.com/od/buyersguideandreviews/f/disk_or_rim_faq.htm:

The biggest downside to disc brakes is the added weight. By the time you add everything in, including front and rear brakes and the added weight of the disc specific hubs, you end up with around 150 to 350 grams additional weight to the whole bike. This weight number greatly depends on the wheels, rims, hubs, and disc brake system you choose.

Do you care about 350 grams? Heck, I can probably take that much weight off by choosing a different pair of pants.

My next commuter will probably have disc breaks. Unfortunately, my current beast is holding up alarmingly well, so it's unlikely a replacement is in the works for quite a while.
posted by larsks at 6:23 PM on December 31, 2008

Leaving aside the debate about whether or not they are necessary on a road bike...

It might sound counter-intuitive, but your departure point here should be determined by your handlebar type. If you are planning on running drop handlebars and using traditional road-style brake levers, then your choices are going to be limited to cable operated calipers. If you are going with flat bars, then your options include both cable and hydraulic units.

Assuming the worst-case scenario - road bars - then your choice narrows down to Avid BB7s, provided that they are marked for road use. Road levers have a different cable pull ratio to mountain levers. Using road levers on MTB cable discs will give you a pretty shithouse lever feel and they won't work terribly well. The good news is that being locked into using Avid BB7 road brakes isn't the end of the world because they are an absolutely terrific product. Easy to set up, easy to adjust, powerful, good modulation etc etc.

If for whatever reason you've got road levers, and by this I also include combination brake/shift levers like the SRAM, Shimano and Campag road levers, and you want to run cable operated disc brakes that are *not* designed for road levers, then there is a slightly kludgy option for you. A company called Problem Solvers make a device called a Travel Agent that adapts the cable pull of the brake lever to the optimum cable pull of the caliper. But hey, if you're building this bike from the ground up, just get BB7 Roads and be done with it.

If on the other hand you're using flat bars, then you have the option of either cable or hydraulic. Hydraulic units should, in theory, offer more power and better modulation. Avid Juicy series brakes are very good performers, as are the corresponding Shimano brakes. My experience tells me to avoid Hayes like the plague, but they may well have corrected their faults in the most recent model update. The UK company Hope make stunning products, but they can be somewhat fiddly to set up and are comparatively pricey. Formula have made big inroads in the last couple of years and are also worthy contenders.

For a commuter however, I can't see any rational reason to go hydraulic. Cable discs are *simple*. If something happens to them on the way to work you probably still stand a good chance on being able to fix them over lunch with a couple of allen keys and a spare cable. Hydros? Forget it. You'd be carrying around cans of DOT5 brake fluid, bleed kits and god knows what else before you could fix them.

My advice would be this:
If you're going with road-style drop bars, get some Avid BB7 road discs. 160mm rotors. If you can't get them or think you might want to change to flar bars in the future, get BB7 MTB discs and a couple of travel agents. If you're going with flat bars, the world is your oyster, but you'd be hard pressed to do any better than BB7s again. Anything advantages that hydros offered you would have little to no relevance on your commute.

ps: brake is what slows your bike down. break is what happens to things to make them broken
posted by tim_in_oz at 1:29 AM on January 1, 2009