Missy Giove's QR pops open
James Annan
go and join up there or Carlton will not be pleased).
James
---------------------------------
Missy Giove's QR pops open
Pilot error? Hardly. Giove was riding a Skareb fork and XT disks in
California on Wednesday. Cycle trainer Dave Smith was with her at the
time and had earlier that day read the BikeBiz.co.uk 'QR/disc-brake'
story and so was clued-up to the probability it wasn't Giove's fault. In
fact, her front QR had been "really tight."
"I was riding with Missy Giove and Rick Sutton [vice president of global
sales and marketing for Trixter, see
http://www.bikebiz.co.uk/web/article.php?id=2908 ] in some big redwood
forest near San Francisco on Wednesday," Smith told BikeBiz.co.uk.
"Missy's QR popped. She had definitely tightened it before the ride as
she was doing some goofy stuff.
"The Skareb had the lawyer lips intact. [The] XT skewer [was] really
tight. I'd actually mentioned your story to Rick when we were leaving
the office."
Giove is planning to publicise her QR popping experience tomorrow at the
Big Bear 2003 NORBA National Championship Series, Snow Summit Resort,
California.
Slacker
That's just beautiful.....I don't suppose her permanent brain damage from going OTB's one too many times has anything to do with it!
--
Slacker
S. Anderson
> go and join up there or Carlton will not be pleased).
>
> James
> ---------------------------------
>
> Missy Giove's QR pops open
>
<<snip..>>
>
Ahhh..sweet vindication!! ;-) Now, let's see if they industry does
anything about it.
Cheers,
Scott..
Phil, Squid-in-Training
So did the lever flip open? Or did the skewer go all the way over the
lawyer lips?
Is she dead?
--
Phil, Squid-in-Training
Carlton Reid, BikeBiz.co.uk
> > Missy Giove's QR pops open
>
> So did the lever flip open? Or did the skewer go all the way over the
> lawyer lips?
>
> Is she dead?
I've updated the article. It's not a bit more subjective:
Friday 16th May 2003
Missy Giove's QR pops open
Pilot error? Maybe, maybe not. Giove was riding a Manitou Skareb fork
and XT disks in California on Wednesday. Cycle trainer Dave Smith was
with her at the time and had earlier that day read the BikeBiz.co.uk
'QR/disc-brake' story and so was clued-up to the possibility (some)
QRs and disc brakes may not mix. Missy's front QR had been "really
tight." But, asks Brant Richards, would zip-ties not be a short-term
answer?
"I was riding with Missy Giove and Rick Sutton [vice president of
global sales and marketing for Trixter, see
http://www.bikebiz.co.uk/web/article.php?id=2908 ] in some big redwood
forest near San Francisco on Wednesday," Dave Smith told
BikeBiz.co.uk.
"Missy's QR popped. She had definitely tightened it before the ride as
she was doing some goofy stuff.
"The Skareb had the lawyer lips intact. [The] XT skewer [was] really
tight. I'd actually mentioned your story to Rick when we were leaving
the office."
On One's Brant Richards is not convinced the 'Missy incident' is the
Annan theory found in the field.
"We don't know how Missy's QR popped open. She could have caught it
trailside on something. It might well have been tight, but might not
have been locked over centre.
"It could have been incorrectly installed, with the clamping surface
not sitting properly in the dropout, and have settled loose, then
flopped open.
"The problem now is people are now suspecting an Annan-type QR/disc
problem, not the fact that something else - several other things -
could have happened!
"We have a rear disc mount on our singlespeed jump frames, and the
relationship of the disc and dropout slot means that certain riders
have noticed the wheel being moved backwards by the force of the disc
brake due to the forces involved. This is only when the wheel is
clamped in place by a chaintug - a device to stop the wheel moving
forwards - which spreads the clamping force over a large area. Use of
just a good old track nut usually stops this in its tracks.
"I therefore don't discount the fact that the physics and my
experience show that a wheel can be shifted in the dropout under
braking load. But I do discount that a correctly installed QR of a
correct over-centre-clamp type lock won't come undone unless it's
disturbed on the trail."
And Richards has a cheap solution:
"Surely something as simple as zip tieing the QR in a closed position
would stop all this. It's the bicycle equivalent of the axle nut split
pin."
Tony Raven
Carlton Reid, BikeBiz.co.uk <car...@bikebiz.co.uk> typed:
>
>
> I've updated the article. It's not a bit more subjective:
>
Quick releases were "coming undone" for years before disk brakes came on the
scene, leading to the infamous "lawyers lips" on drop outs, and many users
then swore they did them up tight. I'm with Brant. There are lots of
alternative ways including operator error why this might have happened but
while the investigations go on into James' theory lets not jump to the
automatic conclusion that every loose QR is a disk brake problem.
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
SuperSlinky
not?
Chris Zacho The Wheelman
since her's were "really tight". If so, a nutted axle could pop out just
as easilly.
Obviously, what's needed here is a redesign of the _fork_. Either by
repositioning the DB mounts , or changing the angle of the dropouts, so
that the braking forces pust the axle into, rather than out of the
dropouts.
May you have the wind at your back.
And a really low gear for the hills!
Chris
Chris'Z Corner
"The Website for the Common Bicyclist":
http://www.geocities.com/czcorner
Jon Isaacs
>alternative ways including operator error why this might have happened but
>while the investigations go on into James' theory lets not jump to the
>automatic conclusion that every loose QR is a disk brake problem.
>
>
I think that the real point is simply that whatever the cause, every loose QR
on a bike with a disk brake is a catastropic accident waiting to happen. It
need not be.
Jon Isaacs
S. Anderson
news:2081-3EC...@storefull-2352.public.lawson.webtv.net...
Yup, that's about it. I mean, we don't really know what happened to
piranha-breath's QR, but there IS a basic design flaw in the rear-mounted
disc brake/vertical dropout/QR fork. As you say, changing the alignment of
the dropout, moving the caliper to the front of the fork and providing a
more positive attachment for the wheel either by closing the bottom of the
dropout with another QR-type swinging plate arrangement or a through-axle
design similar to what is used with motorcycles are all possible fixes.
Now, whether the incidence of this type of failure is high enough to warrant
all that, only time will tell. I mean, I don't think this is happening in
waves with people in emergency rooms all over the world missing front teeth!
But it IS a design flaw that can cause a catastrophic failure. What's it
cost to fix vs. what's it cost to pay off liability claims.
Cheers,
Scott..
Dave Kahn
> Quick releases were "coming undone" for years before disk brakes came on the
> scene, leading to the infamous "lawyers lips" on drop outs, and many users
> then swore they did them up tight. I'm with Brant. There are lots of
> alternative ways including operator error why this might have happened but
> while the investigations go on into James' theory lets not jump to the
> automatic conclusion that every loose QR is a disk brake problem.
Here we have a case of a highly experienced and competent rider taking
particular care to make sure everything was tightly done up and it
still came undone. It might have been the effect James described, it
might have been operator error, or it might have been an incident on
the trail. Whatever the reason it illustrates that they can come
undone when used in this way. It's clearly not a safe configuration.
The zip tie looks like it might work as a fix, but then of course it's
hardly a QR any more. So why bother with one at all?
--
Dave...
Phil, Squid-in-Training
> or later. I know a guy that always used the closed end of a box end
> wrench to close his, he needed a pry bar to open them again and he
> though he was doing the safe thing, until the drop outs on his frame
> spilt.
spilt... their visceral contents a la Hannibal?
--
Phil, Squid-in-Training
Mark Hickey
>Here we have a case of a highly experienced and competent rider taking
>particular care to make sure everything was tightly done up and it
>still came undone. It might have been the effect James described, it
>might have been operator error, or it might have been an incident on
>the trail. Whatever the reason it illustrates that they can come
>undone when used in this way. It's clearly not a safe configuration.
The problem with something like this is that people tend to blame any
possibility OTHER than their own screw-up when something goes wrong.
Remember the infamous Audi unintended acceleration syndrome? 60
minutes (or was it 20/20?) ran a lengthy "expose'" which supressed
clear evidence the car wasn't at fault. They even had an "expert"
mock up a scenario in which the car would accelerate itself (though
the failures required to make it happen were something that had never
happened in the real world). They ignored the "detail" that the woman
who was featured in the piece admits her foot slipped off the brake
onto the gas. Don't let the facts stand in the way of a sensational
story!
Suddenly, dozens of people who hit things with an Audi claimed the car
simply surged out of control despite their valiant efforts to stop it.
However, not once did the accident scene show ANY signs of braking,
nor has anyone ever seen an Audi that the brakes won't outvote the
motor even if it WAS to go ballistic.
I'm afraid we're in for the same phenomenon here. Mistakes clamping
down QR levers are not that uncommon, and there's no reason to believe
that those who ride disc brakes are any less likely to screw up than
others. The real problem is going to be in separating those failures
from any bona fide equipment problems.
Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $695 ti frame
Just zis Guy, you know?
wrote:
>The problem with something like this is that people tend to blame any
>possibility OTHER than their own screw-up when something goes wrong.
Well, QRs have been known to come undone. AIUI James' hypothesis is
more that the braking force can cause the wheel to leave the dropouts,
which according to the mechanics of it could easily happen on a
technical downhill ride.
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.
James Annan
> I've updated the article. It's not a bit more subjective:
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.
> "We have a rear disc mount on our singlespeed jump frames, and the
> relationship of the disc and dropout slot means that certain riders
> have noticed the wheel being moved backwards by the force of the disc
> brake due to the forces involved. This is only when the wheel is
> clamped in place by a chaintug - a device to stop the wheel moving
> forwards - which spreads the clamping force over a large area. Use of
> just a good old track nut usually stops this in its tracks.
>
> "I therefore don't discount the fact that the physics and my
> experience show that a wheel can be shifted in the dropout under
> braking load.
Well, he's half-way there, so I've not completely given up on him. As I
have said before, a bit of reasonable scepticism is a good thing.
> But I do discount that a correctly installed QR of a
> correct over-centre-clamp type lock won't come undone unless it's
> disturbed on the trail."
However, there is no explanation given for the magic fairy dust which
prevents this natural and straightforward failure. At this point a bit
of honest scepticism turns into obstinacy. Why does Brant believe that
it can't fail in this way, given that it is the natural tendency of a
slipping bolt to unscrew and it has also been repeatedly observed?
Elsewhere , Brant also wrote:
> I haven't seen any evidence of vibration-related-unscrewing of the "nut" on the QR lever.
from which I can only assume he hasn't actually bothered to read my
web-page yet:
http://www.ne.jp/asahi/julesandjames/home/disk_and_quick_release/index.html#support
I only put a handful of stories up there (the first and third
specifically mention the unscrewing), but there are many more consistent
tales on the web and in my mailbox. Remember it has only been in the
last few weeks that people have actually known what to look for in
detail. With the common arrangement of the lever on the RHS, the most
the rider will be aware of is an unexplained loosening.
Brant (and several of the other hardened sceptics) seem to be labouring
under a serious misapprehension about this description of the failure
mode. They label it a mere 'theory', spitting this out like it is some
dirty word that requires a mouthwash after uttering. Presumably they
believe I was sitting at my desk, fiddling around with equations in some
hypothetical mathemacial exercise until an answer popped out. Whereas
they are out there in the real world, doing a real man's work, not
worrying their heads about this complicated stuff which scares them. In
fact, it was through looking at the large number of similar stories,
picking out the salient and consistent aspects of the failures, that the
result was generated. I don't have sufficient mechanical engineering
expertise to simply look at the system and work out with any confidence
what will happen from first principles, even though it is quite
straightforward to understand in hindsight.
James
James Annan
> I'm with Brant.
But not, it would appear, with John Forester, who describes the design
as 'gross negligence'.
(JF ascribes the blame to the brake manufacturers, but I'm not convinced
that this is correct - I don't know enough about the evolution of the
design, and anyway at the moment I'm nore interested in the failings
themselves rather than apportioning blame for them).
James
Mike S.
A friend of mine was training at the track a while back. He brought the
bike down to the velodrome in the back of the minivan, started unpacking,
etc. Another mutual friend set up his bike for him. Friend A feels
something funny with the front end of his bike so he lifts the front wheel a
little to see what's going on. Wham! Wheel comes out of the dropouts and
he goes down in a heap.
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? Should I write a paper blaming loose axle nuts and
a lack of "lawyer lips" for the accident? Maybe I can find a more famous
cyclist to claim that the same thing happened to them?
Maybe there's an idiot loose behind the wrench/QR? Maybe we have a case of
"I had a McD's milkshake between my legs, hit a bump, smashed the milkshake
into my lap which distracted me, then I ran into a wall, and its McD's
fault..."
Just zis Guy, you know?
<still_th...@hotmail.com> wrote:
>> I'm with Brant.
>But not, it would appear, with John Forester, who describes the design
>as 'gross negligence'.
Forester, though, was by his own admission instrumental in the
introduction of the execrable "lawyer lips" which are so completely
pointless on any rim-braked fork. Not that this dimishes his status
as a "small god" in the bicycle firmament; but he is after all a
<whisper>lawyer</whisper>.
Just zis Guy, you know?
<still_th...@hotmail.com> wrote:
>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.
Did you see the propsal of the word "Jobstinate" in ?rbm recently? I
recognised the intent immediately :-)
Tony Raven
James Annan <still_th...@hotmail.com> typed:
> Carlton Reid, BikeBiz.co.uk wrote:
>
>> I've updated the article. It's not a bit more subjective:
>
> 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.
</rant>
Tony Raven
Just zis Guy, you know? <guy.c...@spamcop.net> typed:
> On Sun, 18 May 2003 06:07:17 +0900, James Annan
> <still_th...@hotmail.com> wrote:
>
>> 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.
>
> Did you see the propsal of the word "Jobstinate" in ?rbm recently? I
> recognised the intent immediately :-)
>
I think that's Brant (Richards) not (Jobst) Brandt that James is refering
to.
AndyMorris
> I think that's Brant (Richards) not (Jobst) Brandt that James is
> refering to.
>
If he's reading this or goggles himself, did he used to work for us at
TWG/Freewheel in the 80's?
--
Andy Morris
AndyAtJinkasDotFreeserve.Co.UK
Love this:
Put an end to Outlook Express's messy quotes
http://home.in.tum.de/~jain/software/oe-quotefix/
Sorni
news:ba6gog$t2q$1...@news7.svr.pol.co.uk...
> If he's reading this or goggles himself...
Hey! We'll have none of that in these family-oriented newsgroups.
Bill "even the topic sounds rather spanky" S.
S. Anderson
> In news:3EC6A485...@hotmail.com,
>
> 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.
>
> </rant>
>
> 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
>
Somewhat OT, interestingly, cold fusion is enjoying something of a
renaissance. It may not have been wishful thinking after all. Groups have
continued the work started by Fleischmann-Pons and have enjoyed
considerably more success than they did originally. There is some debate
about whether fusion is actually taking place or some other nuclear
interaction that is yet to be explained. So you may have to hold off on
that particular comparison!!
Cheers,
Scott..
Richard Brockie
> I don't have sufficient mechanical engineering
> expertise to simply look at the system and work out with any confidence
> what will happen from first principles, even though it is quite
> straightforward to understand in hindsight.
Such is the way with most discoveries - they generally appear obvious in
hindsight, but it takes a lot of work to extract the salient facts from
the noise.
--
R.
<> Richard Brockie "Categorical statements
<> The tall blond one. always cause trouble."
<> ric...@brockie.org.uk
Richard Brockie
> Somewhat OT, interestingly, cold fusion is enjoying something of a
> renaissance. It may not have been wishful thinking after all. Groups have
> continued the work started by Fleischmann-Pons and have enjoyed
> considerably more success than they did originally. There is some debate
> about whether fusion is actually taking place or some other nuclear
> interaction that is yet to be explained. So you may have to hold off on
> that particular comparison!!
Er, care to substantiate that statement? Cold fusion as proposed by
Fleischmann and Pons has been roundly discredited. There are a few
die-hard advocates who advocate precisely what you state, but the
evidence for their claims is still flimsy, at best.
Jose Rizal
> In
> fact, it was through looking at the large number of similar stories,
> picking out the salient and consistent aspects of the failures, that the
> result was generated. I don't have sufficient mechanical engineering
> expertise to simply look at the system and work out with any confidence
> what will happen from first principles, even though it is quite
> straightforward to understand in hindsight.
I think the mechanism of a QR unscrewing upon cyclic movement along the
dropout is complex enough that any precise mathematical modelling of the
physical process to enable precise predictions of events with certain
inputs (eg how fast will QRs loosen given a certain initial dislodging
force and successive forces causing cyclic movement of the QR) will
require experimental validation. It will be far easier to analyse the
hypothesis and the probability of occurrence by conducting controlled
(laboratory) experiments simulating actual conditions, the results of
which will eliminate any subjectivity on the part of sufferers, and any
doubts from others arising out of this subjectivity (perceived or not).
I think the true value of the anecdotal evidence you have compiled with
respect to QRs loosening is in justifying resources to be allocated (by
manufacturers or consumers) to carry out an experimental investigation
of the hypothesis, such that quantitative arguments can be made for or
against a re-design of the QR/dropout. While I'm convinced that a disc
brake system can exert a force sufficient to eject a wheel "loose"
enough out of a dropout (easily shown experimentally), the waters are
murky on the relationships between initial QR "tightness", axle cyclic
dropout movement magnitude and frequency, whether loosening of the QR
results from this and the rate at which any loosening occurs.
S. Anderson
news:3EC6D450...@reply-to.address...
>
> Er, care to substantiate that statement? Cold fusion as proposed by
> Fleischmann and Pons has been roundly discredited. There are a few
> die-hard advocates who advocate precisely what you state, but the
> evidence for their claims is still flimsy, at best.
>
> --
> R.
>
> <> Richard Brockie "Categorical statements
> <> The tall blond one. always cause trouble."
> <> ric...@brockie.org.uk
>
From Scientific American:
http://www.sciam.com/askexpert_question.cfm?articleID=0007CC4D-394F-1C71-84A
9809EC588EF21
I was careful to indicate in my post that it may not have been cold fusion
at all, but some other interaction. I still remember the debacle and
remember feeling somewhat sadly for the two at being shot down by peer
review. But, that is the point of peer review after all. If I remember
correctly, they were partly a little too aggressive in extolling their
fusion "success" and at the same time became victims of media hype and
shortly afterward, were made goats when their "success" was called into
question. Still, I keep reading in Scientific American and other science
journals that there is a quiet and steady study of the cold fusion
experiments and that something may actually be happening there that was not
originally seen in the peer review experiements. I'm intrigued to see the
outcome.
Cheers!
Scott..
Richard Brockie
> From Scientific American:
>
> http://www.sciam.com/askexpert_question.cfm?articleID=0007CC4D-394F-1C71-84A
> 9809EC588EF21
Thanks - I'll check this out.
> I was careful to indicate in my post that it may not have been cold fusion
> at all, but some other interaction. I still remember the debacle and
> remember feeling somewhat sadly for the two at being shot down by peer
> review. But, that is the point of peer review after all. If I remember
> correctly, they were partly a little too aggressive in extolling their
> fusion "success" and at the same time became victims of media hype and
> shortly afterward, were made goats when their "success" was called into
> question.
That is being charitable. The main problem with Fleischmann and Pons was
that they did not go through the usual peer review process before their
public announcement. For more on the debacle, read "Voodoo Science" by
Robert Park.
Tony Raven
S. Anderson <scott.a...@zsympaticoz.ca> typed:
>
> I was careful to indicate in my post that it may not have been cold
> fusion at all, but some other interaction. I still remember the
> debacle and remember feeling somewhat sadly for the two at being shot
> down by peer review. But, that is the point of peer review after
> all.
But not before quite a few respected scientists had joined their cause.
There is a good book by Robert Park - the author of the seven tests of
"bogus science" - that is well worth reading called Voodoo Science. The
Park tests are at http://chronicle.com/free/v49/i21/21b02001.htm
Dave Kahn
> Forester, though, was by his own admission instrumental in the
> introduction of the execrable "lawyer lips" which are so completely
> pointless on any rim-braked fork.
But not so pointless with a disk brake it seems.
--
Dave...
Dave Kahn
> What I get from this is not that QR's are incompatable with disk brakes,
> since her's were "really tight". If so, a nutted axle could pop out just
> as easilly.
What you're missing is that the QR came undone although it had been
"really tight". With lawyer lips in place there should not be a
catastrophe if the QR stays done up even if the wheel does move. There
are 2 stages to the accident. First the QR comes undone, then the
wheel gets ejected.
--
Dave...
Tony Raven
>
>
http://www.sciam.com/askexpert_question.cfm?articleID=0007CC4D-394F-1C71-84A
> 9809EC588EF21
>
An interesting article with a beautiful illustration of my point about
science and dogma, quote:
"It might be thought that the three Japanese results would be decisive, but
the two summary speakers, Tullio Bressani of Turin and Mike McKubre of SRI
International, were optimistic and *belittled or ignored* them and instead
talked of other experiments that were not performed with the same careful
controls."
Tony Raven
Just zis Guy, you know? <guy.c...@spamcop.net> typed:
>
> Forester, though, was by his own admission instrumental in the
> introduction of the execrable "lawyer lips" which are so completely
> pointless on any rim-braked fork.
...and were introduced for all those people (with rim brakes) whose wheels
came out despite them being absolutely certain they had done the quick
release up properly. Plus ca change......
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
.
Dave Kahn
> > Did you see the propsal of the word "Jobstinate" in ?rbm recently? I
> > recognised the intent immediately :-)
>
> I think that's Brant (Richards) not (Jobst) Brandt that James is refering
> to.
In fact Jobst Brandt seems to be supportive of James' conclusions.
--
Dave...
Just zis Guy, you know?
>> Forester, though, was by his own admission instrumental in the
>> introduction of the execrable "lawyer lips" which are so completely
>> pointless on any rim-braked fork.
>But not so pointless with a disk brake it seems.
Yes - it amused me that years after having introduced an unnecessary
"safety" device for rim-braked bikes, the bike makers finally
introduced a product which made the lawyer lips worthwhile - except
that the only bike I have with disc brakes has no lawyer lips, and the
only bike I have with lawyer lips has rim brakes!
Just zis Guy, you know?
<scott.a...@zsympaticoz.ca> wrote:
>There is some debate
>about whether fusion is actually taking place or some other nuclear
>interaction that is yet to be explained.
That was the view of my friend Séamus, who worked in the lab in
Southampton where some of the initial experiments were done. Séamus
is now Professor of Bio- and Electroanalysis at Cranfield, so was not
standing behind the door when brains were handed out.
James Annan
> 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.
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. If it's just a matter of the time it
takes you to get your head round the idea, that's fair enough and I'm
sorry I was a bit short. It is a bit incredible to believe that all
the major manufacturers can have made this mistake. I suspect that the
problem must have been properly considered a long time ago, but a
combination of corporate memory loss and erroneous copying of designs
has brought us to the current situation.
The ultimate test of a theory is its ability to predict future
outcomes, because that enables it to be falsified or validated. In my
opinion it predicted Spaceman Spiff's experience rather well (quoted
on my page). This anecdote was not one of the ones that I drew on when
dreaming up my ideas, it only happened a couple of weeks ago and you
can therefore treat it as an independent data point for validation.
James
Carlton Reid, BikeBiz.co.uk
> Maybe there's an idiot loose behind the wrench/QR? Maybe we have a case of
> "I had a McD's milkshake between my legs, hit a bump, smashed the milkshake
> into my lap which distracted me, then I ran into a wall, and its McD's
> fault..."
Every sporting activity is now constrained by the safety-Nazis,
sometimes with little or no sense coming into play. [You should see
the daft 'safety instructions' printed on parachute sacks].
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.
Tullio Campangnolo invented the QR in the 1930s. The way QRs are
being currently deployed by many bike suppliers may not be safe in
some situations. Mountain biking is dangerous (if you do it right...)
but if just a handful of people per decade are saved from lifelong,
crippling injuries it's incumbent upon the trade to make the required
changes.
The problem the bike trade has got is admitting there's a problem
because that raises the spectre of a massive recall programme. Many
niche, high-end bike suppliers are already offering bikes that don't
suffer from the problems James Annan decribes. I suspect some of them
were way ahead of James but instead of shouting about it, just quietly
modified their designs, leaving other suppliers with the allegedly
'defective' set-ups.
James Annan
> I think the true value of the anecdotal evidence you have compiled with
> respect to QRs loosening is in justifying resources to be allocated (by
> manufacturers or consumers) to carry out an experimental investigation
> of the hypothesis, such that quantitative arguments can be made for or
> against a re-design of the QR/dropout.
When the design is obviously faulty, I'm not sure why you think this
should be necessary. Even the sceptics are already changing their
designs (certainly Brant Richards, plus several others who have not
actually stated their opinions either way). The point they seem to
dispute is whether this failure has ever occurred in practice, but
since the possibility in any case can be eliminated at next to no
cost, there seems little reason not to do so.
James
Dave Kahn
> > 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...
Dave Kahn
> I did an endo the other day in a panic stop. The QR didn't budge. Why
> not?
Why would you expect it to?
--
Dave...
Dave Kahn
> 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...
Just zis Guy, you know?
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.
SuperSlinky
> Why would you expect it to?
See thread subject.
Tony Raven
Dave Kahn <dkah...@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 Raven
Carlton Reid, BikeBiz.co.uk <car...@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.
James Annan
> 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.
Jose Rizal
Sure, by all means. However, it's clear that not everyone is convinced,
and even if all fork manufacturers change their design, there is still
the matter of owners with the current design where the cost of changing
is not so little. An experimental investigation which seeks to quantify
the mechanism involved in QR behaviour when subjected to loads typical
of disc brake systems, resulting in an ability either to confidently
state that such behaviour is more than just probable or not, will
eliminate sceptics in either camp.
I suspect there may be money to be made in a contraption which can be
retrospectively installed in current fork designs to eliminate possible
movement of the QR in the dropout.
Penny S.
> "Tony Raven" <ju...@raven-family.com> wrote in message
> news:<ba6f7e$pe73m$3...@ID-178940.news.dfncis.de>...
>> In news:3EC6A485...@hotmail.com,
>> James Annan <still_th...@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?
Tony Raven
> 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 Raven
James Annan <still_th...@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 Raven
Penny S. <pennyd...@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.
Leo
news:ba82or$q47dh$3...@ID-178940.news.dfncis.de...
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.
/Leo - giving away ideas for free today... :-)
Just zis Guy, you know?
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.
Tony Raven
Leo <snowro...@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.
Penny S.
> In news:vcf5l9...@corp.supernews.com,
> Penny S. <pennyd...@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
Tony Raven
Penny S. <pennyd...@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.
Just zis Guy, you know?
<pennyd...@invalidcet.com> wrote:
>http://www.specialtyoutdoors.com/pgallery.htm
Heh! Cool.
CtrlAltDel
"James Annan" <still_th...@hotmail.com> wrote in message
news:3EC579C...@hotmail.com...
| Shamelessly stolen from www.bikebiz.co.uk (hope all you industry types
| go and join up there or Carlton will not be pleased).
|
| James
| ---------------------------------
|
| Missy Giove's QR pops open
|
| Pilot error? Hardly. Giove was riding a Skareb fork and XT disks in
| California on Wednesday. Cycle trainer Dave Smith was with her at the
| time and had earlier that day read the BikeBiz.co.uk 'QR/disc-brake'
| story and so was clued-up to the probability it wasn't Giove's fault. In
| fact, her front QR had been "really tight."
|
| "I was riding with Missy Giove and Rick Sutton [vice president of global
| sales and marketing for Trixter, see
| http://www.bikebiz.co.uk/web/article.php?id=2908 ] in some big redwood
| forest near San Francisco on Wednesday," Smith told BikeBiz.co.uk.
|
| "Missy's QR popped. She had definitely tightened it before the ride as
| she was doing some goofy stuff.
|
| "The Skareb had the lawyer lips intact. [The] XT skewer [was] really
| tight. I'd actually mentioned your story to Rick when we were leaving
| the office."
|
| Giove is planning to publicise her QR popping experience tomorrow at the
| Big Bear 2003 NORBA National Championship Series, Snow Summit Resort,
| California.
|
Dave Kahn
> In news:vcf5l9...@corp.supernews.com,
> Penny S. <pennyd...@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.
It is, after all, literally a matter of life or death.
--
Dave...
Just zis Guy, you know?
wrote:
>it's cause she's not right
Which response might make sense if it weren't top-posted on an
untrimmed quote, thus making it impossible to work out which part of
the posting you were agreeing or disagreeing with.
Dave Kahn
> Dave Kahn said...
>
> > Why would you expect it to?
>
> See thread subject.
I suggest you do the same, but this time read it properly.
--
Dave...
Tony Raven
CtrlAltDel <as...@ronco.net> typed:
> it's cause she's not right
>
That's what happens if you use Ronco as your internet provider ;-)
Sorni
> There are essentially two aspects to the failure, the slipping and the
unscrewing.
Let not talk about Rimmer when he's not here to defend himself.
Bill "OK, I'll go ride now" S.
James Messick
> Overall I think it would be sensible to rethink the drop out design
because
> people do forget to do up their QRs quite frequently.
Who? Who? Who are these people forgetting to "do up" there quick releases?
Just zis Guy, you know?
wrote:
>Let not talk about Rimmer when he's not here to defend himself.
Smoke him a kipper, fellas, he'll be back for breakfast...
Tim McNamara
dkah...@yahoo.co.uk (Dave Kahn) wrote:
> Chrisz...@webtv.net (Chris Zacho "The Wheelman") wrote in
> message news:<2081-3EC...@storefull-2352.public.lawson.webtv.net>...
> > What I get from this is not that QR's are incompatable with disk
> > brakes, since her's were "really tight". If so, a nutted axle
> > could pop out just as easilly.
>
> What you're missing is that the QR came undone although it had been
> "really tight". With lawyer lips in place there should not be a
> catastrophe if the QR stays done up even if the wheel does move.
> There are 2 stages to the accident. First the QR comes undone, then
> the wheel gets ejected.
Well, first the axle gets "rocked" in the dropout multiple times,
which begins to unscrew the QR nut. When tension drops on the QR
enough, the lever can be flipped open more easily. However, Annan's
research indicates that the QR can be forced over the lawyer lips even
without the lever flipping open.
Tim McNamara
"Tony Raven" <ju...@raven-family.com> wrote:
> In news:57db8bde.03051...@posting.google.com, Dave Kahn
> <dkah...@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.
Does this invalidate his opinion in some way?
Tim McNamara
"Tony Raven" <ju...@raven-family.com> wrote:
> In news:57db8bde.03051...@posting.google.com, Dave Kahn
> <dkah...@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.
He provides more than "anecdotal" evidence. He provides an analysis
of the forces involved, with reasonable estimates of their magnitude.
Both are based on well-established principles. That's objective
rather than anectdotal evidence. He provides a mechanism that is
likewise based on known and demonstrated facts of mechanical
engineering. Synthesizing the two, he presents a very credible
The "anecdotal" evidence is not what convinced me, as it is too easy
to challenge anecdotes. It was the engineering analysis that
persuaded me, which has already been to a degree peer-reviewed by
other, independent mechanical engineers.
> 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.
And so Mr. Annan should buy a research lab just to satisfy you, simply
because you feel like rejecting the proof he has already offered?
What proof would you accept?
James Annan
> Its for James to
> prove his theory with experimental evidence and demonstrate causality
No it isn't. Frankly I don't give a shit if you believe it or not, I'm
just a bit surprised as you seem generally to be a pretty intelligent
poster. I'm not the one riding around on one of these forks. I've
explained what is going on in simple terms, anyone else's reaction to it
is their own responsibility.
I'm not here to win friends and influence people, not any more. The
people whose opinions actually matter, have already been influenced.
Even if I do manage to offend them, I am confident that they will
consider it their duty to ensure that the problem is solved.
James
James Annan
> Who? Who? Who are these people forgetting to "do up" there quick
releases?
Russ Pinder, Missy Giove, Adrian Carter (Pace Cycles Ltd), Tony Raven,
people like that. Just muppets who don't know one end of a bike from
another, basically.
James
James Annan
> Those who have followed Jobst's comments over the years will know he has
> always been dismissive of disk brakes.
And? You wouldn't happen to be non-scientifically dismissing his opinion
rather than rationally disagreeing with what he said, would you?
James
Tony Raven
James Annan <still_th...@hotmail.com> typed:
>
> No it isn't. Frankly I don't give a shit if you believe it or not, I'm
> just a bit surprised as you seem generally to be a pretty intelligent
> poster. I'm not the one riding around on one of these forks. I've
> explained what is going on in simple terms, anyone else's reaction to
> it is their own responsibility.
>
> I'm not here to win friends and influence people, not any more. The
> people whose opinions actually matter, have already been influenced.
> Even if I do manage to offend them, I am confident that they will
> consider it their duty to ensure that the problem is solved.
>
I retire. You mind has clearly been made up from the beginning so there is
no point continuing this headbanging. Time will tell.
Doug Taylor
Correct me if I'm wrong, but the bulk of Brandt's criticism of disc brakes
(other than the Annan/QR subject) relates to road and not off-road
applications, such as tandems on mountain descents. He doesn't ride
off-road, so his opinions mostly irrelevant in that area. Apples and
oranges.
Spider
> "Tony Raven" <ju...@raven-family.com> wrote in message news:<ba6f7e$pe73m$3...@ID-178940.news.dfncis.de>...
>
> > The difference between science and dogma is science seeks to challenge a
> > theory which is strengthened or dismissed on its ability to meet those
> > challenges.
> Ok then, have a go at challenging it. But let's stick to the
> scientific method, and avoid simply saying "I don't believe it". _Why_
> don't you believe it? There are essentially two aspects to the
> failure, the slipping and the unscrewing. Both are predicted by
> elementary theory, both have been repeatedly observed. I'm at a loss
> takes you to get your head round the idea, that's fair enough and I'm
> sorry I was a bit short. It is a bit incredible to believe that all
> the major manufacturers can have made this mistake. I suspect that the
> problem must have been properly considered a long time ago, but a
> combination of corporate memory loss and erroneous copying of designs
> has brought us to the current situation.
What more do I need to see? Experimental data. Nothing else will
suffice.
> The ultimate test of a theory is its ability to predict future
> outcomes, because that enables it to be falsified or validated.
Not merely "future outcomes," but "future outcomes conducted in a
rigorous, controlled fashion."
Spider
Jose Rizal
> In article <ba8514$q7h6r$2...@ID-178940.news.dfncis.de>,
> "Tony Raven" <ju...@raven-family.com> wrote:
>
> > 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.
>
> He provides more than "anecdotal" evidence. He provides an analysis
> of the forces involved, with reasonable estimates of their magnitude.
> Both are based on well-established principles. That's objective
> rather than anectdotal evidence. He provides a mechanism that is
> likewise based on known and demonstrated facts of mechanical
> engineering. Synthesizing the two, he presents a very credible
No, there has not been any quantitative analysis of the mechanism behind
QRs unscrewing through cyclic movement along the dropout. You might be
referring to the freebody analysis of the disc brake/axle forces, which
are easily dissected. That is a distinct, separate issue.
> The "anecdotal" evidence is not what convinced me, as it is too easy
> to challenge anecdotes. It was the engineering analysis that
> persuaded me, which has already been to a degree peer-reviewed by
> other, independent mechanical engineers.
As far as the potential for disc brakes to eject wheels out of dropouts,
yes, some engineers here have agreed with it because the mechanism is
straightforward and easily demonstrated. As far as QRs loosening
through cyclic movement along dropouts by disc brake force, no one has
"peer-reviewed" any quantitative analysis, for none exists. For the
latter, only anecdotal evidence exists.
> > 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.
>
> And so Mr. Annan should buy a research lab just to satisfy you, simply
> because you feel like rejecting the proof he has already offered?
> What proof would you accept?
No, "someone" should expend resources to gather empirical data from
controlled experiments simulating the QR/disc brake system, to determine
the relationship between initial QR "tightness, likelihood and frequency
of cyclic QR motiom along dropouts, likelihood and rate of unscrewing
QRs while moving along dropouts, and elimination of any subjectivity
from anecdotal data. This is not an unreasonable demand.
Tim Woodall
Just zis Guy, you know? <guy.c...@spamcop.net> wrote:
> On 18 May 2003 03:30:58 -0700, car...@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.
>
>
Infact theory is a very strong description. Hypothesis would be the usual
term to denote what the layman would describe as "just a theory"
Tim.
--
God said, "div D = rho, div B = 0, curl E = - @B/@t, curl H = J + @D/@t,"
and there was light.
Just zis Guy, you know?
<dev...@locofungus.org> wrote:
>> The word "theory" is not in any way pejorative, I would suggest.
>Infact theory is a very strong description. Hypothesis would be the usual
>term to denote what the layman would describe as "just a theory"
Quite. Now, what was it? a hypothesis, tested, becomes a theory; a
theory, proven, becomes a law. Or somthing like that.
Mark Hickey
>On Sat, 17 May 2003 18:33:29 GMT, Mark Hickey <ma...@habcycles.com>
>wrote:
>
>>The problem with something like this is that people tend to blame any
>>possibility OTHER than their own screw-up when something goes wrong.
>
>Well, QRs have been known to come undone. AIUI James' hypothesis is
>more that the braking force can cause the wheel to leave the dropouts,
>which according to the mechanics of it could easily happen on a
>technical downhill ride.
And I don't doubt it. The point I raised, broken down into its base
elements:
1) We know that people who ride non-disc brake bikes occasionally
forget to tighten their QRs properly (even if that means just getting
the "centering springs" pinched between the QR and dropout).
2) If it is shown conclusively that under some very narrow conditions
that an otherwise good QR installed properly can be forced loose by a
front disc brake, it's unlikely that anyone who has a problem with #1
above will ever admit it (even to themselves).
3) As a result, we won't ever really be sure how big the "real
problem" is, only how big the "perceived problem" is. In the case of
the Audi unintended acceleration syndrome, the "real problem" was
virtually non-existant, but the "perceived problem" was big enough to
destroy the resale value of Audis for years.
Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $695 ti frame
Mark Hickey
James - are you saying that the above are incapable of forgetting to
properly tighten their QRs properly? That can happen to anyone, and
refusing to admit that is just another form of "sticking your head in
the sand" you rail against so much. I've helped other riders who
clearly didn't do up their QR properly (no disc brakes to blame). One
went to the hospital for some serious facial reconstruction.
Ask Lynn Hill (premier woman rock climber of all time) about properly
tying in. She was in the top 10 of all climbers in the world at the
time (including men), and got distracted and forgot to properly tie in
before a competition climb. She aced the climb, leaned back and took
an 80 foot fall (luckily only slightly injuring her). If someone as
bright and talented as Lynn Hill can screw up, I don't have a problem
believing Missy could do so as well. That's NOT to say she did, but
that it's poor logic to assume just because someone's a great rider
they're less likely to screw up their QR (many racers know less about
bikes than most recreational riders, IME).
Just zis Guy, you know?
wrote:
>3) As a result, we won't ever really be sure how big the "real
>problem" is, only how big the "perceived problem" is.
Unless the manufacturers get involved and find out, of course, always
assuming that their weasels allow them to tell us the truth. Did I
say weasels? I meant lawyers.
I have actually tried undoing the QR on the front of my bike (no
lawyer lips) and braking. The result was that the wheel jammed at
walking pace. It didn't come out, though. But that wasn't science,
it was tinkering.
FWIW I think the problem demands investigation, simply because the few
times I've raised it with anyone in the industry they have simply not
thought through the different mechanics. And if they haven't thought
about it they surely haven't accounted for it.
I'm suspect a change in dropout angle will do most of what's required,
though.
Jay Beattie
> Tony Raven wrote:
>
> > I'm with Brant.
>
> But not, it would appear, with John Forester, who describes the design
> as 'gross negligence'.
>
> (JF ascribes the blame to the brake manufacturers, but I'm not
convinced
> that this is correct - I don't know enough about the evolution of the
> design, and anyway at the moment I'm nore interested in the failings
> themselves rather than apportioning blame for them).
Forester may be right, but he also may be carving out a niche as a trial
expert in a new litigation market. Many supposed product defects are
the creation of litigation experts -- not always the case, but some
times. Forester has found some pretty benign products to be defective,
like a bike without a factory-installed head lamp. -- Jay Beattie.
Benjamin Weiner
> Correct me if I'm wrong, but the bulk of Brandt's criticism of disc brakes
> (other than the Annan/QR subject) relates to road and not off-road
> applications, such as tandems on mountain descents. He doesn't ride
> off-road, so his opinions mostly irrelevant in that area. Apples and
> oranges.
LOL.
Jobst was riding off road before practically anybody else in the
so-called "birthplace of mountain bikes." Jobst does not ride a
"mountain bike," though; perhaps that is what you were intending?
Here's a fun description of a ride with Jobst:
http://www.geocities.com/rayhosler/jobst/gazos.html
Followups trimmed a bit.
Anthony Sloan
James Annan wrote:
>
> ---------------------------------
>
> Missy Giove's QR pops open
>
> Pilot error? Hardly. Giove was riding a Skareb fork and XT disks in
> California on Wednesday. Cycle trainer Dave Smith was with her at the
> time and had earlier that day read the BikeBiz.co.uk 'QR/disc-brake'
> story and so was clued-up to the probability it wasn't Giove's fault.
> In fact, her front QR had been "really tight."
I'm confused. I understand that disc brakes can exert forces on hubs
that could cause them to walk out of dropouts. But what I don't
understand is how these forces are (supposedly) causing quick release
levers to open of their own accord.
A
James Annan
> 3) As a result, we won't ever really be sure how big the "real
> problem" is, only how big the "perceived problem" is.
Note that according to Trek's comments, they will reliably and
repeatedly misdiagnose this problem as 'operator error'. There are
errors in perception on both side here.
James
James Annan
>>Russ Pinder, Missy Giove, Adrian Carter (Pace Cycles Ltd), Tony Raven,
>>people like that. Just muppets who don't know one end of a bike from
>>another, basically.
>
>
> James - are you saying that the above are incapable of forgetting to
> properly tighten their QRs properly?
The Missy Giove case is not a question of 'forgetting'. Her companion
had just read the articles, and they specifically checked carefully at
the start of the ride. If there is user error here, it is hard to avoid
the interpretation the QR is not capable of being used correctly even by
those at the top end of cycling. Occam's razor starts to cut at this point.
James
Tim McNamara
Anthony Sloan <spam...@spamoff.gov> wrote:
> I'm confused. I understand that disc brakes can exert forces on
> hubs that could cause them to walk out of dropouts. But what I
> don't understand is how these forces are (supposedly) causing quick
> release levers to open of their own accord.
Read Annan's Web site which includes the mechanism whereby the nut on
the QR can be unscrewed. The URL has already been posted several
times in this thread.
SuperSlinky
> I'm confused. I understand that disc brakes can exert forces on hubs
> that could cause them to walk out of dropouts. But what I don't
> understand is how these forces are (supposedly) causing quick release
> levers to open of their own accord.
See http://makeashorterlink.com/?T538360A4 for the long version. I will
concede that he has a point in that the design of the dropouts relative
to the disc brake is not ideal, but a chain of highly unlikely events
has to happen before a wheel would be forced out of the dropouts.
Chris Zacho The Wheelman
"What you're missing is that the QR came undone although it had been
"really tight". With lawyer lips in place there should not be a
catastrophe if the QR stays done up even if the wheel does move. There
are 2 stages to the accident. First the QR comes undone, then the wheel
gets ejected. "
What I'm saying is that, if a "really tight" QR can unscrew enough to
get ejected from the dropout, what's to keep a nutted axle from doing
the same? Lawyer lips or no lawyer lips, the forces acting upon it are
the same.
May you have the wind at your back.
And a really low gear for the hills!
Chris
Chris'Z Corner
"The Website for the Common Bicyclist":
http://www.geocities.com/czcorner
Mark Hickey
Agreed. I'm just hoping we can establish some sort of meaningful
baseline before all objectivity goes out the window. Once the pitch
reaches the "religious fervor level" all bets are off... (think
"greasing cranks"). ;-)
My theory is that for every front wheel that's ejected from the front
of the bike by the disc brake, there have to be many that are "almost
ejected" - whether that's not noticed until the end of the ride
("dang, I thought I tightened that skewer"), or noticed during the
ride ("why's my front wheel flopping around so much?"). In the latter
case, I'd expect to see some pretty significant brake rub between the
time the skewer got loose enough for the wheel to move much, and the
time the wheel would be ready to depart.
How many here who ride disc brakes have noticed either of these things
happening?
Mark Hickey
I believe using Occam's razor "they screwed up" may indeed be the
simplest explanation and bubble to the top. Also, if there's a
liability potential, Missy and/or her friend have every reason to deny
doing up the QR incorrectly. It's certainly not hard to pinch a
centering spring (which will eventually shift, leaving the QR
dangerously loose) - or perhaps install the QR on the upper edge of
the lawyer lip. In either case, it will be good and "tight" without
being "tight".
Again, I'm not saying they DID screw up - but that anecdotal evidence
is nothing more than anecdotal evidence, no matter which way it
points.
Doug Taylor
"Benjamin Weiner" <b...@mambo.ucolick.org> wrote in message
news:3ec89785$1...@news.ucsc.edu...
>Jobst does not ride a "mountain bike," though; perhaps >that is what you
were intending?
Yup.
Van Bagnol
<scott.a...@zsympaticoz.ca> wrote:
> "James Annan" <still_th...@hotmail.com> wrote in message
> news:3EC579C...@hotmail.com...
> > Shamelessly stolen from www.bikebiz.co.uk (hope all you industry types
> > go and join up there or Carlton will not be pleased).
> >
> > Missy Giove's QR pops open
>
> <<snip..>>
>
> Ahhh..sweet vindication!! ;-) Now, let's see if they industry does
> anything about it.
Actually, at one LBS I _did_ see safety-locked quick releases for sale.
You had to push a spring-loaded button in before you can pull the lever
up. IIRC they had versions for both axle skewers and seatpost binders.
For those in the Santa Rosa (Calif.) area, it was at Rincon Cyclery just
off Highway 12.
Van
--
Van Bagnol / v a n at wco dot com / c r l at bagnol dot com
...enjoys - Theatre / Windsurfing / Skydiving / Mountain Biking
...feels - "Parang lumalakad ako sa loob ng paniginip"
...thinks - "An Error is Not a Mistake ... Unless You Refuse to Correct It"
James Annan
> It's certainly not hard to pinch a
> centering spring (which will eventually shift, leaving the QR
> dangerously loose) - or perhaps install the QR on the upper edge of
> the lawyer lip.
You seem to be arguing very strongly that the QR is not a suitable
fastener for the front wheel of any bicycle, not just one with disk
brakes. Remember, we are not here talking about the general population
being careless, but experienced cyclists who are paying particular
attention to this danger. If you really think it's too difficult for
them to use correctly, under those conditions, then who exactly do you
think they are suitable for?
James
James Annan
> See http://makeashorterlink.com/?T538360A4 for the long version. I will
> concede that he has a point in that the design of the dropouts relative
> to the disc brake is not ideal, but a chain of highly unlikely events
> has to happen before a wheel would be forced out of the dropouts.
Yup, that's about right (for some as yet unknown value of 'highly
unlikely'). Hence, we have a load of people saying it's never happened
to them, and a smaller number in hospital with serious injuries.
James
Ryan Cousineau
still_th...@hotmail.com (James Annan) wrote:
There's a nice, tidy statistics joke about this:
If something is a one-in-a-million chance, that means it's going to
happen 300 times in the USA.
Or 6000 times worldwide,
--
Ryan Cousineau, rcou...@sfu.ca http://www.sfu.ca/~rcousine
President, Fabrizio Mazzoleni Fan Club
Dave Kahn
Which, going back to your earlier post, is the reason your QR didn't
budge when you did an endo the other day in a panic stop. As you have
now worked out this is perfectly in accordance with James' analysis.
--
Dave...
Andy Dingley
Annan) wrote:
>You seem to be arguing very strongly that the QR is not a suitable
>fastener for the front wheel of any bicycle, not just one with disk
>brakes.
There's a good argument that nothing short of welding is a suitable
fastener for Missy's front wheel.
QR's - one M4 thread shearing and your wheel's off. Not entirely
encouraging for D/H.
Clive George
news:jl7kcvc61g6mjqq59...@4ax.com...
> QR's - one M4 thread shearing and your wheel's off. Not entirely
> encouraging for D/H.
(actually M5). But this is presumably why 20mm non-qr axle is used by DH
people.
cheers,
clive