Why disc brakes on a commuter bike?
10-31-10, 04:23 PM
#53
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The disc brake essentially adds the same type of loading on the wheel as a cog/cassette, i.e. torque loads carried from the hub flange to the spokes (which is okay). There should be no "lateral" loading of any component, unless there is significant bending of the axle itself during braking.
A properly built wheel is more than adequate to handle any of the stresses involved with disc brakes.
My commuter now has discs, and I prefer the all-weather performance to any rim brakes I've used in numerous applications (racing, commuting, mountain biking) over the years. I do like high-end v-brakes, and consider them to be an appropriate alternative, but in snow country, the discs are far better (cleaner, more reliable, no rim wear concerns, etc) IMO.
Last edited by canyoneagle; 10-31-10 at 11:45 PM.
10-31-10, 04:26 PM
#54
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I'm thinking Avid started mass producing mechanical disc brakes in '99
11-01-10, 07:22 AM
#55
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Unlike cargo nets, disc brakes do not cause cancer in California.
After several wide swings in predictability of bad weather braking power using v-brakes (even with salmon kool stops), I switched my commuter to an Avid BB7s (front only) and am very glad I did. When I built a from-scratch commuter, I did the same thing.
You can chatter forever about the number of issues that might cause disc brakes to be a bad or unnecessary alternative for some people, some situations, etc. But it is pretty much a basic truth that they stop better in a broad range of conditions. And that's what matters to me on 3/5 of my bikes.
After several wide swings in predictability of bad weather braking power using v-brakes (even with salmon kool stops), I switched my commuter to an Avid BB7s (front only) and am very glad I did. When I built a from-scratch commuter, I did the same thing.
You can chatter forever about the number of issues that might cause disc brakes to be a bad or unnecessary alternative for some people, some situations, etc. But it is pretty much a basic truth that they stop better in a broad range of conditions. And that's what matters to me on 3/5 of my bikes.
11-01-10, 01:10 PM
#56
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With a disk brake, the calipers apply pressure to the disk, which in turn applies pressure to the hub, which applies the lateral pressure to the rim and then the tire through the spokes. The spokes (especially on a front wheel) are primarily designed to apply radial, not lateral pressure, so in order to accommodate the braking forces, you will want to use a lacing pattern which takes this into account. The net result will be more, longer, and beefier spokes on the front wheel than you would otherwise need.
The next issue is one of thermal dissipation - when you are slowing your bike, you are doing so by converting the kinetic energy of the bicycle to thermal energy, mostly in the brake pads and the braking surface. In the case of a traditional brake, this heat is generated in the rim of the wheel, and there is a lot of area over which it can be distributed, and dissipated. With a disk brake, all this thermal energy is transferred into a relatively small disk.
I'll grant that choosing mechs over hydros makes sense due to simplicity and not having to maintain a hydraulic system. But mechs are pretty good these days.
11-01-10, 02:24 PM
#57
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I've run into brake fade using disc brakes...on my mountain bike descending 5000 feet over 12 miles. And even then I was able to brake, just with reduced effectivness. I doubt that many commuters are descending that far or that fast.
As far as cost/ease of replacement, the pads cost about the same, and it takes me no longer to replace the pads on Avid BB7 brakes than it does to replace traditional canti brake pads. Both need ocassional adjustment as they wear, and they both last about the same amount of time.
The big advantage for discs is when you ride a lot in the snow or rain (like we do here in the Pacific Northwest). In the rain, discs outperform rim brakes every time.
As far as cost/ease of replacement, the pads cost about the same, and it takes me no longer to replace the pads on Avid BB7 brakes than it does to replace traditional canti brake pads. Both need ocassional adjustment as they wear, and they both last about the same amount of time.
The big advantage for discs is when you ride a lot in the snow or rain (like we do here in the Pacific Northwest). In the rain, discs outperform rim brakes every time.
11-01-10, 03:56 PM
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history of bicycle brakes: https://en.wikipedia.org/wiki/Bicycle_brake_systems
history of disc brakes: https://en.wikipedia.org/wiki/Disc_brake
why disc brakes on a commuter bike? because spoons are so 18th Century
history of disc brakes: https://en.wikipedia.org/wiki/Disc_brake
why disc brakes on a commuter bike? because spoons are so 18th Century
11-02-10, 03:19 AM
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Well, everyone can believe, discuss, think what they like, it's not like it's going to make a difference to me. I use discs simply because of one reason - they work, in all conditions, in all weather. Without fail, they just simply WORK. Oh I've tried all the best V's out there, including XTR's and SD 7's, but, for some conditions V-brakes don't work for me. Dropping 5 mph per second in an emergency stopping situation in wet is not braking to me, it's sh**. But BB7's plain simply WORK. No if's, but's, what's. They WORK. Discussion over 
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