On Jun 25, 4:10*pm, Opus wrote:
On Jun 25, 2:38 pm, Andre Jute wrote:snip
Gee. I know the RBT readers are supercyclists who wear their
underpants over the rest of their clothes, but how many
1. Are capable of going to places where it is possible to induce such
extreme conditions?
2. Haver ever cycled or will ever cycle in such places?
3. Having reached there, are stupid enough to cycle in such a
dangerous manner as to induce such conditions?
4. Having induced such conditions, are stupid enough not to notice?
5. Having noticed, are so thick as not immediately to take the
necessary counter-measures?
I have seen bicycles that set their brakes on fire stopping after a
straight line run on level ground, at Battle Mountain NV.
I'll leave that one to the local scoffjaws, who're just engaging motor-
drive.
I have
personally experienced tire failure due to brake heat riding down Big
Cottonwood Canyon east of SLC UT.
Why don't you tell us how long and steep this ride is, how
irresponsibly you rode down there, how the tire failed, how you
determined that it was due to brake heat. Note that I never said it is
impossible, merely that the circumstances are rare and avoidable.
Hell, consider this sequence of facts. Jobst reported the other day
that he got up to 50mph or 80kph down some notorious mountain in
California. *If his brake pads faded, never mind failed to stop him
(or melted!), you can bet we would have heard of it. I needed truck
assistance to get up to 100kph, and had to stop in a hurry afterwards
to avoid crossing a dangerous intersection (or, as bad, hitting the
back of my own truck). Neither disc brakes nor roller brakes got too
warm to touch.. I didn't at the time have a bike with rim brakes but I
do now and often ride the brakes down long descents so as not to speed
ahead of my pedalpals -- result: at worst a slightly warmed rim. Hard
braking from over 50kph at the bottom of a hill makes no impression
either, as I've reported here before.
Sounds to me like this German test proves that existing bicycle brakes
are plenty good enough, and that venting is an affectation, just like
you say.
The best reason for disc brakes has nothing to do with heat. Rim
brakes use the rim as a friction surface, which destroys the rim over
time. Disc brakes remove that source of wear from a soft aluminum or
carbon fiber rim to something designed to be a consumable item.
I agree with you. If you read the archives, you will find me saying
so.
Mountain bikers and bike tourists can wear out a rim in just a single
season of riding in muddy conditions as the pads and the dirt combine
to form an abrasive slurry applied under high pressure against the
rim. The same issues apply to cyclocross in which the UCI recently
banned the use of discs. I guess the "purity" of the sport out weighed
actually making it affordable to run over extended periods of time
without costly parts replacement.
Well, here we drift out of agreement again. I think discs and their
maintenance are too expensive, though it is true that wheel rebuilding
because the rim is worn through is also very expensive. But the
solution is roller brakes. I have Shimano's 70/75 series rollerbrakes
on my Cyber Nexus Trek, and they're every bit as good as disc brakes,
but cost a tiny fraction in maintenance. You can see my Trek Smover
with these excellent enclosed brakes at:
http://www.audio-talk.co.uk/fiultra/...%20Smover.html
Andre Jute
I'm not cheap, I'm poor!