Disc brake failure in CX...

It turns out cheating at CX is harder than I thought.

I run Shimano cable-actuated discs on my cheater CX bike. It was
designed to be mud-proof.

Today, we finally had a race with epic rain and mud. It was great. The
first few laps, I confidently used my sweet brakes to go hard into some
pretty mucky terrain.

Then my brakes failed completely. Both ends. As in virtually zero
braking. I was able to demonstrate for people later that I could pull
the levers to the bar and roll the bike without serious resistance.

Considering this race had at least one steep and mucky descent, it got
pretty interesting!

So I get back to the pit, and it turns out a teammate, running Avid
cable discs, had exactly the same symptoms.

Anyone else seen this? I haven't taken the brakes apart yet to see what
happened to the pads. I'll let you know.

--
Ryan Cousineau http://www.wiredcola.com/
"My scenarios may give the impression I could be an excellent crook.
Not true - I am a talented lawyer." - Sandy in rec.bicycles.racing

Ryan Cousineau wrote:
It turns out cheating at CX is harder than I thought.

I run Shimano cable-actuated discs on my cheater CX bike. It was
designed to be mud-proof.

Today, we finally had a race with epic rain and mud. It was great. The
first few laps, I confidently used my sweet brakes to go hard into some
pretty mucky terrain.

Then my brakes failed completely. Both ends. As in virtually zero
braking. I was able to demonstrate for people later that I could pull
the levers to the bar and roll the bike without serious resistance.

There you go. UCI knows best.

Per Ryan Cousineau:

So I get back to the pit, and it turns out a teammate, running Avid
cable discs, had exactly the same symptoms.

Anyone else seen this? I haven't taken the brakes apart yet to see what
happened to the pads. I'll let you know.

Could mud on the rotors be a player?

I've had a rear disc fail 100%.

The internal-geared hub I was using dripped a little oil on the
rotor.
--
PeteCresswell

On Sun, 09 Nov 2008 21:53:05 +0000, Ryan Cousineau wrote:

It turns out cheating at CX is harder than I thought.

I run Shimano cable-actuated discs on my cheater CX bike. It was
designed to be mud-proof.

Today, we finally had a race with epic rain and mud. It was great. The
first few laps, I confidently used my sweet brakes to go hard into some
pretty mucky terrain.

Then my brakes failed completely. Both ends. As in virtually zero
braking. I was able to demonstrate for people later that I could pull
the levers to the bar and roll the bike without serious resistance.

Considering this race had at least one steep and mucky descent, it got
pretty interesting!

So I get back to the pit, and it turns out a teammate, running Avid
cable discs, had exactly the same symptoms.

Anyone else seen this? I haven't taken the brakes apart yet to see what
happened to the pads. I'll let you know.


if they're the cheapo cable actuated shimano calipers, did you also use
the cheapo shimano low end barely-perforated disks? because the higher
end more-perforated ones are much less susceptible.

Per Ryan Cousineau:
So I get back to the pit, and it turns out a teammate, running Avid
cable discs, had exactly the same symptoms.

Anyone else seen this? I haven't taken the brakes apart yet to see what
happened to the pads. I'll let you know.

(PeteCresswell) wrote:
Could mud on the rotors be a player?

I've had a rear disc fail 100%.

The internal-geared hub I was using dripped a little oil on the
rotor.

Uh oh. I believe this Ryan's bike with the Alfine hub.

But that doesn't explain why the front failed. Hmm...

--
Paul M. Hobson
..:change the f to ph to reply:.

In article ,
"Paul M. Hobson" wrote:

Per Ryan Cousineau:
So I get back to the pit, and it turns out a teammate, running Avid
cable discs, had exactly the same symptoms.

Anyone else seen this? I haven't taken the brakes apart yet to see what
happened to the pads. I'll let you know.

(PeteCresswell) wrote:
Could mud on the rotors be a player?

There was mud everywhere. There was mud in my hair, mud on my face, mud
on every part of the bike. As I sit here typing this, I'm still picking
bits of mud from behind my ears. The discs definitely had a mud-scoured
look about them, but had you asked me before the race, I would have
expected them to be fairly self-cleaning. After all, rim brakes are.

These pads are no longer exerting any pressure on the rotors to speak
of. I would have assumed loose cable bolts, except that it happened to
all the brakes on two different bikes.

I've had a rear disc fail 100%.

The internal-geared hub I was using dripped a little oil on the
rotor.

Uh oh. I believe this Ryan's bike with the Alfine hub.

Correct.

But that doesn't explain why the front failed. Hmm...

Correct.

--
Ryan Cousineau http://www.wiredcola.com/
"In other newsgroups, they killfile trolls."
"In rec.bicycles.racing, we coach them."

On Nov 9, 9:53*pm, Ryan Cousineau wrote:
It turns out cheating at CX is harder than I thought.

I run Shimano cable-actuated discs on my cheater CX bike. It was
designed to be mud-proof.

Today, we finally had a race with epic rain and mud. It was great. The
first few laps, I confidently used my sweet brakes to go hard into some
pretty mucky terrain.

Then my brakes failed completely. Both ends. As in virtually zero
braking. I was able to demonstrate for people later that I could pull
the levers to the bar and roll the bike without serious resistance.

Considering this race had at least one steep and mucky descent, it got
pretty interesting!

So I get back to the pit, and it turns out a teammate, running Avid
cable discs, had exactly the same symptoms.

Anyone else seen this? I haven't taken the brakes apart yet to see what
happened to the pads. I'll let you know.

I think you'll find the pads just wore out, Ryan, and you'll also
find, if they're the pads that came with the brakes, that they're
"organic". Anyone with low-end (and some high-end "environmentally
aware") disc brakes knows the symptoms, and has had a scary experience
or two. The brakes just keep on going, and then suddenly, even if
brand new or apparently thick on the pre-race check, they get some mud
(or even just dust and a little water) on them and the wear rate
shoots up logarithmically. Sintered or metallic brakes do not display
this accelerated failure mode but they squeal and require more bedding-
in and are said to be less good in the wet than the organic kind. At
the mailorder discounters the two kinds of pad cost about the same, so
I suggest you try metallic pads if you're going to be riding in the
mud, and put up with the squeal when you ride in more civilized
surrounding.

The above is given from experience. I have also heard that sintered
pads are not as longlasting (under ideal conditions) as organic pads,
but have no experience as my disc brake pads all seem to last about a
thousand miles (no offroading, only clean rain).

I had one truly frightening experience. I check the pads about
monthly. I was riding this bike with half-worn pads when it started
raining. Maybe the pads were dusty from just standing; there was
certainly no mud on them. It started raining just as I reached the top
of one of my favourite hills and started the long downhill section,
which at the bottom has a couple of sharp blind turns and then a six-
way junction often with farm machinery on it; hard braking is required
even under ideal circumstances because the only runoff is an
impenetrable bramble hedge that'll chew you up and won't spit you out
again. When I braked, the bike slowed a little, and then there was
nothing, it just spurted forward again on the fall of the road. Just
like that. I took my chances with the road (I still had the rear
roller brake and could thus "lay the bike down" if necessary, spin it
out) and fortunately there wasn't a big tractor on it, but I can't
claim it is a day I remember fondly. I'm too old for gratuitous
adrenalin... I checked and found that the Shimano literature carries a
waning about this sort of behaviour of pads; I'd even read it before,
but missed the point that it could happen with dramatic suddenness.

HTH.

Andre Jute
http://members.lycos.co.uk/fiultra/B...20CYCLING.html

"Andre Jute" wrote in message
...

I think you'll find the pads just wore out, Ryan, and you'll also
find, if they're the pads that came with the brakes, that they're
"organic". Anyone with low-end (and some high-end "environmentally
aware") disc brakes knows the symptoms, and has had a scary experience
or two. The brakes just keep on going, and then suddenly, even if
brand new or apparently thick on the pre-race check, they get some mud
(or even just dust and a little water) on them and the wear rate
shoots up logarithmically. Sintered or metallic brakes do not display
this accelerated failure mode but they squeal and require more bedding-
in and are said to be less good in the wet than the organic kind. At
the mailorder discounters the two kinds of pad cost about the same, so

That sort of makes old fashioned pinch brakes seem pretty effective.

On Nov 9, 11:27*pm, "Tom Kunich" cyclintom@yahoo. com wrote:
"Andre Jute" wrote in message

...



I think you'll find the pads just wore out, Ryan, and you'll also
find, if they're the pads that came with the brakes, that they're
"organic". Anyone with low-end (and some high-end "environmentally
aware") disc brakes knows the symptoms, and has had a scary experience
or two. The brakes just keep on going, and then suddenly, even if
brand new or apparently thick on the pre-race check, they get some mud
(or even just dust and a little water) on them and the wear rate
shoots up logarithmically. Sintered or metallic brakes do not display
this accelerated failure mode but they squeal and require more bedding-
in and are said to be less good in the wet than the organic kind. At
the mailorder discounters the two kinds of pad cost about the same, so

That sort of makes old fashioned pinch brakes seem pretty effective.

No such thing as a free lunch, Tom. Disc brakes may, as Jim Beam says,
be the cat's whiskers, but they require a certain level of awareness
which isn't quite maintenance. That's one of the reasons I love roller
brakes, they're the true set and forget brake. But I don't know that I
would take Ryan's Ride with rollerbrakes...

Did you see Chalo's very interesting post about the advantages of rim
brakes a few days ago? I'm trying to decide on buying or building up a
Rohloff bike. The distinguishing feature of a bike with one hub
costing well over a grand is that price cannot be the absolute final
arbiter. So it is probably indicative that an amazing number of the
available bikes with Rohloff rear ends use the Magura HS-11 or -33
hydraulic rim brakes, which cost half as much again as the cheaper
disc brakes from good-name manufacturers. I started noticing after
studying Chalo's letter.

Andre Jute
Ein perfektes Sorglos-Rad für Schöngeister -- not with disc brakes it
ain't!

"Andre Jute" wrote in message
...

Did you see Chalo's very interesting post about the advantages of rim
brakes a few days ago?

No, and it isn't on my list either. Hmmm, what group did he post in?