On Friday, March 15, 2019 at 4:32:23 PM UTC-7, John B. Slocomb wrote:
On Fri, 15 Mar 2019 17:22:58 +1100, James
wrote:

On 15/3/19 5:01 pm, John B. Slocomb wrote:
On Fri, 15 Mar 2019 11:57:26 +0700, John B. Slocomb
wrote:

On Fri, 15 Mar 2019 15:24:05 +1100, James
wrote:

On 15/3/19 1:50 pm, John B. Slocomb wrote:
On Fri, 15 Mar 2019 12:36:42 +1100, James
wrote:

On 15/3/19 2:17 am, Frank Krygowski wrote:
On 3/13/2019 6:32 PM, Joerg wrote:
On 2019-03-12 11:13, AMuzi wrote:

How many new bicycles have drum brakes? Vanishingly few.


(MUCH DELETED)

And rim brake callipers that go around fat tyres often flex a lot and
don't work so well. So disc brakes for fat tyre bikes are a better
choice, and rim brakes for racing bikes with skinny tyres are pretty good.

Don't use calipers. Try cantilever or the more modern Shimano
V-brakes. They don't care how wide the tire is.

As an addendum: While cheaper they do look a bit low budget so, as one
might say, who would one want a $10 brake on a $3,000 bicycle... even
if they do stop well :-)


I've had canti brakes on a MTB. Yes the rims took a hammering.

It comes to mind that as the braking resistance is applied at the
contact of the tire and the road and that the resistance is applied to
the wheel hub that a much stronger disc brake wheel would be required
than when using a rim brake as the ratio between the disc brake disc
and the contact with the road is approximately 26.5"/7.5" (average 2
sizes of disc rotor) = about 3.5 ratio while a rim brake is only about
an inch and a half difference so say 26.5/23.5=1.1 ratio. Based on
braking forces it would appear that a disc brake wheel would have to
be roughly 3 times stronger than a rim brake wheel.

36 spoke, cross three, wheels anyone?

But of course an ATB is already so heavy that the addition of strong
wheels is rather a matter of bringing coals to Newcastle.

My disc wheels haven't exploded so far, and I've been riding home-built disc wheels on cheap hubs (M525 or SP PD8 dyno) and relatively cheap rims (CR 18 or now out of production Velocity touring disc) for about 15 years. I even have a Vuelta el-cheapo disc that has held up well. I bought the first generation Cannondale CADDX CX bike with discs before they were UCI legal for cyclocross -- which is why I dropped out of racing CX as a pro in Europe. If they wouldn't accept my brakes, I wasn't going to race there. It has been my commuter for years, along with its replacement (yes, I broke the original frame -- broken frame number 7(? could be more)). My other bikes with disc wheels are doing fine, too.

-- Jay Beattie.