Thread: Road Discs
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Old September 10th 17, 04:31 PM posted to rec.bicycles.tech
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Default Road Discs

On Sunday, September 10, 2017 at 4:24:13 AM UTC-7, Ned Mantei wrote:
On 10-09-17 00:28, jbeattie wrote:
So, my SuperSix was crushed in a roof-rack accident and last weak my Roubaix was stolen out of the garage that I left open all night. I've done that many times -- apparently one too many. I'm down to a gravel bike and my commuter -- the reborn warranty CAADX (which is a great bike).

The gravel bike is a pig, but I'll use that for fall/winter/spring sport riding. I want a fast bike, though -- and I've got a line on a nice bike that I can get with rim brakes or discs, but the disc model will not be available until December -- which really means that I get to ride it in dry weather some time around May. I can get a rim brake model by the end of the month.

All the shops are pushing discs, and I did like the discs on the Roubaix and on my gravel bike. I know this is absolutely the wrong group to ask because it's wall-to-wall curmudgeons, but if you were buying your last nice road bike, would you go rim brakes or discs? It will be a dry weather bike or ridden in the rain only because of bad luck. There would be no real weight penalty because the bike is so light to start with. I'm not aero, so I don't care about the aero penalty with discs.

My concern with getting rim brakes is not really even a performance issue because in dry weather, I've never had a problem with rim brakes -- but to listen to the guys at the local shop, rim brakes are going the way of the dodo. I'm worried about buying an antique!

-- Jay Beattie.


I have bikes with rim brakes and one with disc brakes. My experience:

1) With rim brakes obviously the rims will wear out after some years. I
spoke new rims to the old hub and spokes. Since I have very little
practice doing this, it takes me maybe 4 hours to get the spokes
transferred, the wheel reasonably centered and round, and the spokes
evenly tensioned.

2) I bought a mountain bike with disc brakes last October. The first
change of brake pads came in April, and a few days ago I had to install
a new disc on the back wheel (the original disc was worn to the safe
limit). Both things are a lot quicker than spoking a rim, but at least
here in Switzerland rather expensive.

3) With rim brakes I would have pain in my hands from braking during a
long descent in the mountains. Much less or no problem with disc brakes,
which require less pressure. But I'm old, and a younger person probably
wouldn't notice this.

4) Again as an issue on very long descents, I no longer worry about a
tube failure because the rim overheated (happened to me once many years
ago, https://flic.kr/p/9XmmWn ). Disc brakes can also overheat, and then
fade, but this hasn't been a problem for me.

Overall I prefer the disc brakes, but should note that I have no
experience with road bikes.


Ned, my experience is that the so-called advantages of disk brakes are their downfall.

1. Where you need the brakes the most - descents particularly on twisting roads or sharp turns and the like - you have your hands on the brakes. Disks are so powerful that if you hit a bump you are very likely to pull on the brakes while trying to keep yourself from being thrown off of the bike. This pulls the brake on and with all it's power can stop the front wheel completely rotating the entire bike around the front wheel. Voice of experience.

2. Because the whole idea is power the leverage has to be effectively very high. This means the distance of motion must be very low since the lever has limited motion due to your hand size. So brake pads are VERY thin and because they are small they wear very rapidly.

3. Yes it's easier to replace a disk than a rim. In 40 years of riding I've had to replace one rim from brake pad wear. Since I built many wheels it took me a half hour from start to finish. But of course I do have a wheel stand and spoke tools. Now in Switzerland you may have a hell of a lot more sharp and dangerous descents than we do around here but in the last five years on just ONE altimeter that I used on only some of my bikes I do have 57,000 feet of climbing shown. I have worn some brake shoes to the extent that I replaced them. But only on super-light alloy wheels have I ever shown extensive wear. And I find buying new wheels generally cheaper than buying a new rim. I just bought two sets of Campy Scirocco CX's (stronger than the road version) for $240 per set. These are cheap wheels but I am getting tired of spokes breaking on the lighter road wheels.
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