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Missy Giove's QR pops open - Page 3  

post #31 of 255

Re: Missy Giove's QR pops open

"Mike S." <mikeshaw2@coxDOTnet> wrote in message news:<fcyxa.35850$eJ2.9502@fed1read07>...

> Seems friend B forgot to tell Friend A that he didn't tighten the axle nuts holding the wheel on.
>
> So what do we have here?

A red herring.

--
Dave...
post #32 of 255

Re: Missy Giove's QR pops open

On 18 May 2003 03:30:58 -0700, carlton@bikebiz.co.uk (Carlton Reid, BikeBiz.co.uk) wrote:

>James' theory (and I'll continue to call it a theory, even if he believes I'm sneering when I'm
>writing it!) needs to be taken seriously by the global bike trade because it appears to be easily
>solved by manufacturers.

The word "theory" is not in any way pejorative, I would suggest.

Guy
===
** WARNING ** This posting may contain traces of irony. http://www.chapmancentral.com (BT ADSL and
dynamic DNS permitting)
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work. Apologies.
post #33 of 255

Re: Missy Giove's QR pops open

"Tony Raven" <junk@raven-family.com> wrote in message
news:<ba6f7e$pe73m$3@ID-178940.news.dfncis.de>...
> In news:3EC6A485.7020201@hotmail.com, James Annan <still_the_same_me@hotmail.com> typed:

> > You should have trusted your first instincts. But looking on the bright side, this does give
> > Brant's nonsense a public viewing rather than clogging up my mailbox.
>
> The difference between science and dogma is science seeks to challenge a theory which is
> strengthened or dismissed on its ability to meet those challenges. Dogma dismisses and belittles
> anyone who dares question it. N-rays and cold fusion both happened because people were preoccupied
> with seeing manifestations of what they wanted to believe. There may or may not be something in
> your theory but you do it no credit by attacking anyone who dares to question it.

But the challenging of a theory is supposed to be done on a scientific basis. Simply saying "the
theory is wrong" is not scientific. Failing to consider the available evidence is also unscientific.
If the unscrewing mechanism is wrong it deserves a proper rebuttal. James' robust response is
entirely justified in this case.

--
Dave...
post #34 of 255

Re: Missy Giove's QR pops open

In news:57db8bde.0305180023.4996cbdf@posting.google.com, Dave Kahn <dkahn400@yahoo.co.uk> typed:
>
> In fact Jobst Brandt seems to be supportive of James' conclusions.

Those who have followed Jobst's comments over the years will know he has always been dismissive of
disk brakes.

Tony

--
http://www.raven-family.com

"All truth goes through three steps: First, it is ridiculed. Second, it is violently opposed.
Finally, it is accepted as self-evident." Arthur Schopenhauer
post #35 of 255

Re: Missy Giove's QR pops open

In news:8fd6f3b7.0305180230.ed3e6ba@posting.google.com, Carlton Reid, BikeBiz.co.uk
<carlton@bikebiz.co.uk> typed:
>
> However, James' theory (and I'll continue to call it a theory, even if he believes I'm sneering
> when I'm writing it!) needs to be taken seriously by the global bike trade because it appears to
> be easily solved by manufacturers.
>

Totally agree on both points.

Tony

--
http://www.raven-family.com

"All truth goes through three steps: First, it is ridiculed. Second, it is violently opposed.
Finally, it is accepted as self-evident." Arthur Schopenhauer
post #36 of 255
Thread Starter 

Re: Missy Giove's QR pops open

Carlton Reid, BikeBiz.co.uk wrote:

> However, James' theory (and I'll continue to call it a theory, even if he believes I'm sneering
> when I'm writing it!) needs to be taken seriously by the global bike trade because it appears to
> be easily solved by manufacturers.

I've no particular beef with your contribution. It is impressive what a difference you have made in
giving this issue a higher profile. However with the power comes some responsibility, and it is one
measure of a good journalist to work out which sources can give useful input in particular areas.

> The problem the bike trade has got is admitting there's a problem because that raises the spectre
> of a massive recall programme.

On the other hand, they will also realise that if they sit on their hands, a civil liability can
turn into a criminal one.

James

PS It occurs to me that some of the contributors reading in uk.rec.cycling might not have seen the
threads that have been recently running on rec.bicycles.tech. Many of the obvious questions have
already been asked and answered.

http://groups.google.com/groups?hl=e...2E.1080101%40-
hotmail.com&rnum=2&prev=/groups%3Fsafe%3Dimages%26ie%3DUTF-8%26oe%3DUTF-8%26as_uauthors%3Djames%252-
0annan%26lr%3D%26hl%3Den

http://groups.google.com/groups?hl=e...CE.5060100%40-
hotmail.com&rnum=5&prev=/groups%3Fsafe%3Dimages%26ie%3DUTF-8%26oe%3DUTF-8%26as_uauthors%3Djames%252-
0annan%26lr%3D%26hl%3Den
post #37 of 255

Re: Missy Giove's QR pops open

In news:57db8bde.0305180325.1aeb7d97@posting.google.com, Dave Kahn <dkahn400@yahoo.co.uk> typed:
>
> But the challenging of a theory is supposed to be done on a scientific basis. Simply saying "the
> theory is wrong" is not scientific. Failing to consider the available evidence is also
> unscientific. If the unscrewing mechanism is wrong it deserves a proper rebuttal. James' robust
> response is entirely justified in this case.

The available evidence is anecdotal. Anecdotal evidence is notoriously unreliable and not proof. The
unscrewing mechanism has to be demonstrated in practice in controlled conditions by the proposer.
Its for James to prove his theory with experimental evidence and demonstrate causality, not me to
disprove it. Until he does it is just speculation.

I am not saying his theory does not justify investigation. I am not saying it is wrong. I am saying
it is a theory and the proof remains to be done. Until that proof is done, James should rise to the
challenge and not pillory those who ask for the proof.

Tony

--
http://www.raven-family.com

"All truth goes through three steps: First, it is ridiculed. Second, it is violently opposed.
Finally, it is accepted as self-evident." Arthur Schopenhauer
post #38 of 255

Re: Missy Giove's QR pops open

Dave Kahn thoughtfully penned:
> "Tony Raven" <junk@raven-family.com> wrote in message
> news:<ba6f7e$pe73m$3@ID-178940.news.dfncis.de>...
>> In news:3EC6A485.7020201@hotmail.com, James Annan <still_the_same_me@hotmail.com> typed:
>
>>> You should have trusted your first instincts. But looking on the bright side, this does give
>>> Brant's nonsense a public viewing rather than clogging up my mailbox.
>>
>> The difference between science and dogma is science seeks to challenge a theory which is
>> strengthened or dismissed on its ability to meet those challenges.

yawn, would you guys take it back to rbt?
post #39 of 255

Re: Missy Giove's QR pops open (long)

In news:c96ea403.0305180122.3029c7e8@posting.google.com, James Annan
<still_the_same_me@hotmail.com> typed:
>
> Ok then, have a go at challenging it. But let's stick to the scientific method, and avoid simply
> saying "I don't believe it". _Why_ don't you believe it? There are essentially two aspects to the
> failure, the slipping and the unscrewing. Both are predicted by elementary theory, both have been
> repeatedly observed. I'm at a loss to see what more you can need.

OK. There are three element not two, the proposition that the disk brake will eject an unconstrained
wheel from the drop out, the proposition that the QR is insufficient to constrain the wheel against
those forces and the proposition that a mechanism exists to loosen the QR sufficient for it to pass
the other constraining mechanism, the lawyers lips.

The first proposition is reasonable and as can be easily demonstrated by taking the QR out an
unconstrained wheel will eject in many designs of drop out. This is undesirable because people
sometimes forget to do up the QR. It could be easily fixed by having for example a forward facing
drop out or as on my old forks a drop out direction and disk mount that put the braking force
essentially at right angles to the exit path.

The second proposition may be true for some designs of QR's and is easily checked by static load
tests - the University of Kansas study gives some data in that respect. For Shimano QR's there is
evidence that used normally they will easily resist the same or greater loads than you calculate in
the disk brake scenario. An example is the rear wheel on a fixed. With horizontal dropouts the chain
is trying to pull the axle along the drop out. The force on the chain when standing on the RH pedal
on the down stroke is the weight of the rider times the ratio of the crank arm to chain ring radius.
Typically this is 2.3 times bodyweight, maybe more if pulling up on the bars, and repeated regularly
on each of many pedal strokes when climbing. In my case this force is approx 2700N and is held
without trouble by a Shimano QR done up normally and considerably more than the figures you are
estimating for wheel ejection. I cannot speak for other QRs but until some have been tested under
normal usage with static loading its not possible to say whether a slipping wheel in a dropout is a
generic QR problem or one of specific QRs.

The third proposition is that the QR can loosen enough to get past the lawyers lips. You have
proposed a mechanism by which that may happen. What remains to be shown is that that or another as
yet unidentified mechanism is actually happening in real life with QRs. It has to be a disk brake
specific mechanism otherwise QRs on the many road bikes would be mysteriously loosening on the road
and I have not heard of that as a recognised problem since Mr Campag introduced them to cycling.
Anecdotal evidence is not sufficient. Lawyers lips were introduced because people were not doing up
their QRs properly and having wheels fall out long before disk brakes came on the scene. I have
forgotten to do up my QR on occasions and noticed pretty quickly because the handling was "loose".

"My QR was undone/loose and I am certain I did it up before I set out" anecdotes are not proof of
your proposed mechanism happening. It is proof that people, as they were in the days before disk
brakes and lawyers lips, are human and that there are other reasons that Brant Richards refers to
that can cause QRs to undo. I see for example a surprising number of QR's with the lever pointing
forward for a wayward stick or rock can catch and undo it. The two tests I would suggest that need
doing are to see if you can simulate a done up QR loosening in the lab by the mechanism you propose.
The other easy to do one would be to take a mass event such as one of the 24 hour races. Have
testers checking the QR's on every bike setting out to ensure they are done up properly and check
them again when they come back in, noting any crashes/punctures or loose wheels that the rider had
while out. You should pretty quickly get some statistics on whether QRs confirmed as done up are
loosening in normal use in the absence of other interventions. Incidentally try riding cautiously a
bike with the QR undone enough to exit the lawyers lips. Its pretty noticeable.

If proposition one and two are happening a study of accident comparing Pace forks with all other
makes should show a significantly higher rate of "failures" with the Pace forks since they have no
lawyers lips. This means they only need propositions one and two to be happen for an ejection which
is considerably more likely than all three propositions being true which is a necessary condition
for all other forks. Also Pace forks are generally ridden by enthusiasts who will ride more
frequently, aggressively and brake harder on average than the users of most other makes. I've not
heard of Pace forks having a reputation for "failing" which wheel ejection on the carbon legs would
almost certainly cause but maybe Carlton can comment from an industry perspective. For the rest of
the forks proposition 3 has to occur as well

Overall I think it would be sensible to rethink the drop out design because people do forget to do
up their QRs quite frequently. The more normal case you are proposing of propositions 2 and 3 are,
at this stage, propositions remaining to be proven. There are some relatively simple tests that can
be done - static holding tests on QR's, investigation of fork failure statistics between Pace and
other makes, controlled tests at a mass event and lab demonstration of a done up QR loosening as you
suggest. Until then we should treat it as an interesting theory that deserves further investigation
but not proven

Tony

--
http://www.raven-family.com

"All truth goes through three steps: First, it is ridiculed. Second, it is violently opposed.
Finally, it is accepted as self-evident." Arthur Schopenhauer
post #40 of 255

Re: Missy Giove's QR pops open

In news:vcf5l944nse60@corp.supernews.com, Penny S. <pennydeletes@invalidcet.com> typed:
>
> yawn, would you guys take it back to rbt?

Feel free to start your own threads on cycling topics that interest you if you don't like the
ones on offer.

Tony

--
http://www.raven-family.com

"All truth goes through three steps: First, it is ridiculed. Second, it is violently opposed.
Finally, it is accepted as self-evident." Arthur Schopenhauer
post #41 of 255

Re: Missy Giove's QR pops open

In news:zsNxa.9710$dP1.17620@newsc.telia.net, Leo <snowrollerNO@SPAMhotmail.com> typed:
>
> The solution for this problem is simple, just put the discbrake on the frontside of the fork leg
> instead. That way the braking forces will press the wheel even tighter up instead of down. Who
> will be first with this? Maybe Manitou?! Reverse Arch was a brilliant idea.
>

I'd favour it staying at the back out of the way of being hit by rocks and branches. Forward facing
drop outs would do fine. Disk brakes would push sideways on the wall and rim brakes backwards into
the drop out.

Tony

--
http://www.raven-family.com

"All truth goes through three steps: First, it is ridiculed. Second, it is violently opposed.
Finally, it is accepted as self-evident." Arthur Schopenhauer
post #42 of 255

Re: Missy Giove's QR pops open

On Sun, 18 May 2003 15:15:43 GMT, "Leo" <snowrollerNO@SPAMhotmail.com> wrote:

>just put the discbrake on the frontside of the fork leg instead. That way the braking forces will
>press the wheel even tighter up instead of down.

Puts the welds in tension rather than compression - which may not be a Good Thing.

Guy
===
** WARNING ** This posting may contain traces of irony. http://www.chapmancentral.com (BT ADSL and
dynamic DNS permitting)
NOTE: BT Openworld have now blocked port 25 (without notice), so old mail addresses may no longer
work. Apologies.
post #43 of 255

Re: Missy Giove's QR pops open

Tony Raven thoughtfully penned:
> In news:vcf5l944nse60@corp.supernews.com, Penny S. <pennydeletes@invalidcet.com> typed:
>>
>> yawn, would you guys take it back to rbt?
>
> Feel free to start your own threads on cycling topics that interest you if you don't like the ones
> on offer.
>
> Tony

mmm, OK.... and in good amb fashion I will derail this for you:

Been sewing more bike gear, you can see how the custom bike silk screens came out, and another
jersey I made...

http://www.specialtyoutdoors.com/pgallery.htm

Penny
post #44 of 255

Re: Missy Giove's QR pops open

In news:vcfa105jvhqb4e@corp.supernews.com, Penny S. <pennydeletes@invalidcet.com> typed:
>
> mmm, OK.... and in good amb fashion I will derail this for you:
>
> Been sewing more bike gear, you can see how the custom bike silk screens came out, and another
> jersey I made...
>
> http://www.specialtyoutdoors.com/pgallery.htm
>

Not derailed at all. Its cycling related. Nice threads. Feel free to post. If people are interested
they will join in.

Tony

--
http://www.raven-family.com

"All truth goes through three steps: First, it is ridiculed. Second, it is violently opposed.
Finally, it is accepted as self-evident." Arthur Schopenhauer
post #45 of 255

Re: Missy Giove's QR pops open

On Sun, 18 May 2003 08:31:56 -0700, "Penny S." <pennydeletes@invalidcet.com> wrote:

>http://www.specialtyoutdoors.com/pgallery.htm

Heh! Cool.

Guy
===
** WARNING ** This posting may contain traces of irony. http://www.chapmancentral.com (BT ADSL and
dynamic DNS permitting)
NOTE: BT Openworld have now blocked port 25 (without notice), so old mail addresses may no longer
work. Apologies.
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