Cannondale's tests of disks and QRs

Chris Phillipo opined the following...
You are talking about slight brake pad rub and I am talking about the
rotor being jammed into the side of the caliper and the axle is shifted
by braking forces acting on an open QR. It doesn't stop the wheel
completely but you sure as hell will notice it.

I'm talking about where your attention is when rattling downhill. If it
has got bad enough to be noticeable you're not going to get much warning
before you pitch over the bars and it's highly unlikely that you'll be
able to do anything about it.

No one should be doing "real" DH these days without a QR20 front hub
anyway.

What is "real" DH? Is there a minimum gradient where it goes from
"flat" to DH? Does a tricky downhill section on a long X-country ride
count, or is it invalid as you started out with different intentions in
mind? ;-)

Jon

"SuperSlinky" wrote in message
t...
Alan Braggins said...

From here it looks like he's fed up with people nitpicking and/or
repeating
arguments that have already been gone over many times before, and he's
fed
up with going over his theory again and again for people who assume it
can't possibly be right without looking at it properly.
Some of which may rub off even on people who aren't doing that.

You know, I'd like to see one post from the UK from somebody who isn't
rooting for 'our guy'. Quite a number of things about this preposterous
argument leave me scratching my head. James does not live or work in the
USA. His bike was not made in the USA. In fact, it was UK made, if I am
not mistaken, and lack of retention lips on UK made forks is the rule,
not the exception. If his bike had them, we wouldn't be hearing this
nonsense. Yet here he is whining to the _American_ CPSC and publicly
trashing on an _American_ manufacturer who almost certainly has never
sold a disc equipped bike without retention lips. The claim that skewers
loosen by applying a disc brake was a pipe dream to begin with and
doesn't have a shred of evidence to back it up.

The American CPSC listened to him and an American manufacturer performed
a test for which results are available. What are the UK equivalent to
the American CPSC and UK manufacturers doing to investigate James' bold
claims? Nothing? Something? If there is a story there, let's hear it.
But methinks there is more to this than we are being told. Clearly,
something more than selfless altruism is fueling James' dogged
determination to make something of this. Maybe it is only pride and a
desperate need to never be proven wrong. Maybe he is doing the legwork
for somebody's dream of a lucrative lawsuit. If that were the case, then
American manufacturers would certainly be a juicier target than the ones
who are really to blame for the origins of this nonsense.

An american manufacturer(s) will shortly (if it hasn't already happened) be
asked along to a US venue to witness the inspection of some US mtb forks
where the US QR axle has come open and the wheel ejected causing serious
injury with a view to lodging a multi million dollar lawsuit. I know this as
a fact.

I also know this is not the only legal case based on wheel ejection
progressing through the US legal system.

More I am unable to tell you at this stage for obvious reasons

Ex Disc User

wrote:

He gives the impression of someone who fancies himself as a
whistleblower, but so far he isn't blowing any whistle about
this test.

You are correct, Carl. It is quite unfair of me to expect readers of
r.b.t to be capable of analysing the details I have provided (I think
most on uk.r.c. managed, but they are a superior breed).

The reason for the slight delay is that I thought it would be polite to
give Cannondale the opportunity to defend their testing procedure before
I published my criticism of it.

http://www.ne.jp/asahi/julesandjames...annondale.html

Cannondale appear to have nothing to say, but if they do reply, I'll
keep you updated.

James
--
If I have seen further than others, it is
by treading on the toes of giants.
http://www.ne.jp/asahi/julesandjames/home/

"Ex Disc User" notonline@here wrote in message
...
"SuperSlinky" wrote in message
t...
Alan Braggins said...

From here it looks like he's fed up with people nitpicking
and/or
repeating
arguments that have already been gone over many times
before, and he's
fed
up with going over his theory again and again for people who
assume it
can't possibly be right without looking at it properly.
Some of which may rub off even on people who aren't doing
that.

You know, I'd like to see one post from the UK from somebody
who isn't
rooting for 'our guy'. Quite a number of things about this
preposterous
argument leave me scratching my head. James does not live or
work in the
USA. His bike was not made in the USA. In fact, it was UK
made, if I am
not mistaken, and lack of retention lips on UK made forks is
the rule,
not the exception. If his bike had them, we wouldn't be
hearing this
nonsense. Yet here he is whining to the _American_ CPSC and
publicly
trashing on an _American_ manufacturer who almost certainly
has never
sold a disc equipped bike without retention lips. The claim
that skewers
loosen by applying a disc brake was a pipe dream to begin
with and
doesn't have a shred of evidence to back it up.

The American CPSC listened to him and an American
manufacturer performed
a test for which results are available. What are the UK
equivalent to
the American CPSC and UK manufacturers doing to investigate
James' bold
claims? Nothing? Something? If there is a story there, let's
hear it.
But methinks there is more to this than we are being told.
Clearly,
something more than selfless altruism is fueling James'
dogged
determination to make something of this. Maybe it is only
pride and a
desperate need to never be proven wrong. Maybe he is doing
the legwork
for somebody's dream of a lucrative lawsuit. If that were the
case, then
American manufacturers would certainly be a juicier target
than the ones
who are really to blame for the origins of this nonsense.

An american manufacturer(s) will shortly (if it hasn't already
happened) be
asked along to a US venue to witness the inspection of some US
mtb forks
where the US QR axle has come open and the wheel ejected
causing serious
injury with a view to lodging a multi million dollar lawsuit. I
know this as
a fact.

I also know this is not the only legal case based on wheel
ejection
progressing through the US legal system.

More I am unable to tell you at this stage for obvious reasons

Wow, this is so mysterious! I just love a mystery! -- Mysterious
Person.

SuperSlinky wrote in message et...
SuperSlinky said...

The American CPSC listened to him and an American manufacturer performed
a test for which results are available. What are the UK equivalent to
the American CPSC and UK manufacturers doing to investigate James' bold
claims? Nothing? Something? If there is a story there, let's hear it.

Cue sound of a forlorn wind blowing through a desert landscape. Yep,
just what I thought. A British rider has a mechanical failure on a
British made bike and somehow the whole thing gets twisted into a bunch
of mudslinging against the American CPSC and an American manufacturer
who doesn't even make a bike anything like the original perp in this
fiasco. ROTFLMAO. That's just too funny.

Lots of fun watching you dig your own grave, but if you had looked at
James' website, you'd see that he has 3 tandems.

A Cannondale:-

http://www.ne.jp/asahi/julesandjames..._tour/sign.jpg

Handmade in the USA


A Ventana:-

http://www.ne.jp/asahi/julesandjames...e/bamboo_1.jpg

oooo - Handmade in the USA


A Calfee:-

http://www.ne.jp/asahi/julesandjames...kies/garth.jpg

yet again - Handmade in the USA


Seems you lose that one.

twinks

Ex Disc User said...

An american manufacturer(s) will shortly (if it hasn't already happened) be
asked along to a US venue to witness the inspection of some US mtb forks
where the US QR axle has come open and the wheel ejected causing serious
injury with a view to lodging a multi million dollar lawsuit. I know this as
a fact.

I also know this is not the only legal case based on wheel ejection
progressing through the US legal system.

More I am unable to tell you at this stage for obvious reasons

Ex Disc User

Wow, what a shock. I must be clairvoyant. Nah, just follow the money...

This thread is beyond ridiculous.

James has pointed out that there is a possibility that a wheel could be
ejected if:
1) the fork has no retention ring
2) the QR is seated improperly

Maybe im wrong, but i dont think he guaranteed that a wheel would be
ejected. just that it is possible.
We can all make sure the next fork we buy has retention rings. We can
make sure th QR is tight before riding.
I never thought about retention rings and QR untill James made a big
deal out of it, so he may have prevented me from crashing, who knows.
I will still ride disc, but at least i am aware.

The Cannondale test.
James- along with criticizing thier test (which is probably
insufficient) send them the type of riding conditions you would like to
see recreated or experiment yourself. Yes they performed bad tests but
maybe they don't understand your theory the same way you do.

OK. Now theres not really anything left to argue about.


--
Mr_Kingkillaha

SuperSlinky wrote in message et...

Wow, what a shock. I must be clairvoyant. Nah, just follow the money...


So was it not SuperSlinky (SuperWimpy perhaps?) who ran snivelling to
a lawyer when he got his knee bloodied recently:-

http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&c2coff=1&safe=images&selm=MPG.1bafecd1c1cc136998 9947%40netnews.comcast.net&prev=/groups%3Fq%3Dlawyer%2Bauthor:nospam%2540least.com% 26hl%3Den%26lr%3D%26ie%3DUTF-8%26c2coff%3D1%26safe%3Dimages%26scoring%3Dd%26fil ter%3D0

"I am in contact with lawyers now and have been since the second day
after the accident."


twinks

"Ex Disc User" notonline@here wrote in message news:
An american manufacturer(s) will shortly (if it hasn't already happened) be
asked along to a US venue to witness the inspection of some US mtb forks
where the US QR axle has come open and the wheel ejected causing serious
injury with a view to lodging a multi million dollar lawsuit. I know this as
a fact.

I also know this is not the only legal case based on wheel ejection
progressing through the US legal system.

More I am unable to tell you at this stage for obvious reasons

Ex Disc User

The fact that someone is trying their luck through the US legal system
does not add any credence to the validity of their proposition. After
all it may be just opportunism.

I have tried to understand James' description and think it is flawed.
His diagram shows forces D and B but he doesn't show the reaction
forces -D and -B which are transmitted through the structure of the
disc, hub, spokes, rim and tyres to the front axle. Without those
forces there would be no braking moment to slow down the rotation of
the wheel. I therefore contend that under normal braking conditions
(no slipping) the axle (QR) is pushed upwards and forwards.

The proposition that the QR can be ejected as a result of braking in
my view is hogwash. That view is supported by practical experience in
that when one uses the front brake on a bike then the front gets
compresssed not extended as the ejection theory would have it.

Pieter

On 25 Sep 2004 04:51:17 -0700, (Pieter) wrote in
message :

I have tried to understand James' description and think it is flawed.
His diagram shows forces D and B but he doesn't show the reaction
forces -D and -B which are transmitted through the structure of the
disc, hub, spokes, rim and tyres to the front axle.

It is not necessary to show how braking force is transmitted through
the structure of the wheel in order to understand how the resultantof
forces at the dropout could cause the wheel to be ejected.

Whatever your view on the argument, there is no possible doubt that in
the case of disc brakes there is a significant resultant component of
force tending to eject the wheel, which component is essentially
absent from rim-braked wheels. It is also clear that the geometry of
dropouts is founded on rim brakes not discs, and somewhere along the
line "they" simply forgot to think about it.

I therefore contend that under normal braking conditions
(no slipping) the axle (QR) is pushed upwards and forwards.

This is a very curious statement. Are you saying that if the QR
doesn't slip it doesn't slip? Or that if you lock the brakes it
doesn't slip?

I have bikes with and without discs. It was a simple matter to loosen
the QR on both types, hit the brake with the bike moving along
(pushing, I'm not stupid enough to try it while riding), and observe
the result.

It was an unnecessary experiment, as elementary static mechanics has
already provided the answer, but I have a literal mind so I tried it
anyway.

The disc-braked wheel moved down in the dropouts, the rim-braked wheel
did not.

There are two questions remaining: first, does this force ever
overcome the retaiing force exerted by the QR skewer; second, does
the repeated application of these large off-centre forces cause a QR
to loosen. Cannondales tests do not answer either of these questions
because the braking force was inadequate, the vibration was inadequate
and the downforce on the handlebars was excessive in comparison. So
the questions remain unanswered.

I think James' arguments are plausible. The fact that Cannondale's
tests were so obviously hopeless does little to reassure me.

The proposition that the QR can be ejected as a result of braking in
my view is hogwash.

You might want to run that by Russ Pinder.

That view is supported by practical experience in
that when one uses the front brake on a bike then the front gets
compresssed not extended as the ejection theory would have it.

The explanation of why there is a resultant force tending to eject the
wheel is very clear, and mechanically unassailable. Whether that
force, or its repeated application, can result in the QR loosening or
slipping, is unproven. I think James' argument is plausible, but I
don't think he has the resources necessary to run the necessary
experiments. Cannondale - who do have the resources - seem to have
worked surprisingly hard to ensure that they never got close to
real-world forces, which some may see as telling and others may count
as merely incompetent.

Guy
--
May contain traces of irony. Contents liable to settle after posting.
http://www.chapmancentral.co.uk

88% of helmet statistics are made up, 65% of them at Washington University