On Tue, 10 Oct 2006 00:04:56 CST, Chris_MdR@[EMAIL PROTECTED]
wrote:
>
>Hi,
>
> I tried a bike with hydraulic disk brakes (Hayes Sole V6) yesterday
>for the first time, and would appreciate your input on my impressions:
>
> - On the first bike I tried, it was not possible to block the wheel
>with the disk brake. I checked and found that the disk was oily.
Well, that would explain it. BTW, a brake which locks the front wheel
when the bike is actually being ridden can be an unpleasant thing to
have. If you get one, I suspect that you will discover this at some
point.
> On
>another bike (same brake) I was able to get the wheel to block, but
>with application of extreme force to the brake handle, MUCH more than
>required by any V brake I ever tried.
>
>Question: Are Hydraulic Brakes really weaker than V brakes, or was this
>bike just assembled by monkeys?
In my experience, most v-brakes require far less finger pressure to
produce a given amount of stopping power than a disc brake.
> - I noticed that the hydraulic disc brakes have a much 'spongier' feel
>than the cable actuated V brakes. This I guess was related to the
>hydraulic hose / brake line expanding under pressure, because it was ok
>on the front brake (1/2 of the brake lever way until full braking), and
>not acceptable no the rear brake (had to pull the brake lever almost up
>to the handle bar to get full breaking power)
Cable-operated disc brakes often have similar results. This is not
unusual for disc brakes as a class of unit, but results vary wildly
between setups; it is foolish to infer anything about a specific
brake's probable operating characteristics on the basis of other
brands or models. The only way to reliably establish what a given
brake does is to try it and see.
>Question: Is this again a problem of monkey assembly (not enough
>fluid?, air in the lines?, what else? ...), or cheap brake lines, or
>both? And are there better brake lines that expand less than the stock
>ones?
To each: Possibly.
>Or ARE hydraulic disc brakes just spongier? If yes, that much
>spongier??
Any brake can be made to work poorly. Some can't be made to work
well. Each must be evaluated on its own merits.
> - After playing with the brakes for a few minutes, I noticed that the
>discs get noticeably warm, around 170F.
Gosh, you had a contact thermometer available? I'm impressed.
>Are there ever heating issues
>with disc brakes on longer downhill segments? Seems a stupid question,
>but they did get quite warm just by playing around on level ground for
>about ten minutes.
Yes, it is possible to get disc brakes hot enough on a long descent
(especially with a heavy rider or on a steep grade) to discolor the
disc. Whether this is a problem depends on other factors that vary
from brake to brake.
>PS: All the monkey references are founded on an employee there telling
>me that 'there are no electrical brakes' when I asked for differences
>between hydraulic and cable actuated.
Correct: there are no electric brakes. If you used the term "cable
actuated" they should have known you were talking about something that
was not electrically operated, how did you manage to get them to think
that an electrical connection was involved?
>When I asked her that about the
>front fork maxing out, i.e. hitting the limit of it's travel hard, she
>replied with 'many people like their forks soft'. (I found out how they
>can be adjusted later.)
What does this have to do with brakes?
>When I showed her that the (later found to be
>well oiled) disk didn't stop the bike, she said 'Oh. Eh? Uh?'
Oil contamination of disc brakes has been an issue with motorcycles as
well, for much longer. It happens. When the pads get oiled, you
generally have to replace them; if they're getting oiled by a leaking
fork, then you need a better fork. In the case of bicycles, the best
solution is often to go back to V-brakes, but not always.
>So monkeys or Neanderthals are definitely a possibility in that store.
>But the bike is on sale, so I might still buy there. Uh. Uh. Uh. I
I think I'd shop for something else.
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