Carlton Reid on QR safety



Quoting [email protected] <[email protected]>:
>Your comment gave me an idea for a simple experiment. I went out to the
>garage, lifted the front wheel of my mountain bike, gave the front
>wheel a sharp spin, and, still holding the bike up, slammed on the disk
>brake, stopping the wheel violently.


But the front wheel weighs a tiny fraction of what the bike and rider
does. It can't put that much oomph into the quick-release.
--
David Damerell <[email protected]> Kill the tomato!
Today is First Sunday, February - a weekend.
 
"jim beam" <[email protected]> wrote in message
news:[email protected]...

> i mean this seriously - if you weren't such a jerk and played a straight
> game, you'd stand a chance of making a contribution, but the way you're
> acting now, like an abused 2 year old with an attention-seeking tantrum,
> you're just pissing any chance of credibility away. why do you act up
> like this? are you at risk of having to return to your homeland and the
> beatings you received as a kid? i'd be interested to observe the british
> climatology community's reaction to your employability.


I've got it! "jim beam" is James' sock puppet - why else post all this stuff
making James look sensible?

cheers,
clive
 
In article <[email protected]>, dvt ([email protected])
wrote:

> Could a riders' dropouts have the same characteristic? Should a bike
> rider be required to know about work hardening before (s)he uses a disk
> brake?


Yes, and ideally they should install new dropouts every time the q/r is
operated...

--
Dave Larrington - <http://www.legslarry.beerdrinkers.co.uk/>
While you were out at the Rollright Stones, I came and set fire to your
Shed.
 
jim beam wrote:
> the much-vaunted "howat" paper shows
> retention exceeding the "annan factor" by a substantial margin.


Where is that shown? I find the opposite.

--
Dave
dvt at psu dot edu
 
Quoting Ed Pirrero <[email protected]>:
>G.T. wrote:
>>Wow, your mind works in mysterious ways.

>I understand that. In a world filled with emotional rhetoric and
>name-calling, I seek facts.


It must have been some other <[email protected]> who explicitly stated
they help with the name-calling, I suppose?

>I guess that's why I do science for a living.


In some way carefully hidden from Google. Of course. Funny how most of the
scientists I know are pretty keen to be visible on the Web...
--
David Damerell <[email protected]> Kill the tomato!
Today is First Sunday, February - a weekend.
 
Quoting Ed Pirrero <[email protected]>:
>Maybe. Since it has never been directly measured, we actually have no
>idea how large the force actually is.


Unless we have some knowledge of basic mechanics, that is. This is like
saying we don't know the weight of an object of known size and density at
sea level unless we personally put it on some scales...
--
David Damerell <[email protected]> Kill the tomato!
Today is First Sunday, February - a weekend.
 
Quoting Luke <[email protected]>:
><[email protected]> wrote:
>>Correct, no disk brakes involved at all. But clear evidence of wheel
>>loss and serious injury due to an ejection force (gravity) in the
>>direction of the drop-out opening and failure of the retention
>>mechanisms to retain the wheel against the ejection force. Design flaw
>>or not design flaw?

>Are you being facetious?


The point that Mr Raven is making - quite correctly - is that you started
with the assertion that an ejection force in the direction of the dropout
opening was an inherently bad thing without reference to the magnitude of
that force. His observation about gravity demonstrates why reference _to_
the magnitude of the force is absolutely necessary.
--
David Damerell <[email protected]> Kill the tomato!
Today is First Sunday, February - a weekend.
 
David Damerell wrote:
> Quoting Ed Pirrero <[email protected]>:
> >G.T. wrote:
> >>Wow, your mind works in mysterious ways.

> >I understand that. In a world filled with emotional rhetoric and
> >name-calling, I seek facts.

>
> It must have been some other <[email protected]> who explicitly stated
> they help with the name-calling, I suppose?


Don't throw stones when your abode is made of glass.

> >I guess that's why I do science for a living.

>
> In some way carefully hidden from Google. Of course. Funny how most of the
> scientists I know are pretty keen to be visible on the Web...


Logical fallacy: ad hominem.

E.P.
 
jim beam wrote:
> James Annan wrote:
> > jim beam wrote:
> >
> >
> >> "interference between materials"??? "dead end"? so how come /i/ am
> >> the poor dolt that had to point out that axle faces are serrated and
> >> that subsequent indentation significantly increases retention force?
> >> i can't see you bothering to point out such trivial details tim.
> >>

> >
> > All I need to do is point to the pictures that jim beam so kindly
> > provided:
> >
> > http://home.comcast.net/~carlfogel/download/nishiki_before.jpeg
> > http://home.comcast.net/~carlfogel/download/nishiki_indent.jpeg
> >
> > Of course, a particularly dull-witted person might not wonder why it is
> > that someone (who?) bothered to scrape the paint off the dropout of an
> > old fork that happened to be lying around, nor what the picture might
> > have looked like had the fork end been left normally painted. But I
> > think most people reading this thread will have got the message clearly
> > enough.

>
> eh? that's spectacular b.s. that is a fork i happened to have laying
> about. the paint was already off. the snide implication that i somehow
> "prepared" it to alter the result is as bogus as it is desperate. it
> also shows incredible ignorance if you think a simple paint layer offers
> any significant resistance to steel indentors.


Yes, it does. I did the experiments, I reported the results. Google
for them if you can't remember.

> i can see b.s. may be the only way you could have any come-back on the
> evidence annan, but resorting to such a pathetic diversion is below even
> you. integrity and credibility go hand in hand, in case you never
> learned it before. [why did you leave scotland again?]
>
> >
> > Of course, for those who are still unconvinced, there is also Marvin's
> > comment posted earlier:
> >
> > "Every new bike I assembled today, I checked before and after on the
> > indentations. All of them embossed the paint to a fairly minor degree
> > with a single clamping, repeated clampings on one test subject made
> > them a little more obvious. None of them were to the same level as jim
> > beam's example above."
> >
> >
> > James

>
> straw clutch city. that was from a single thumb-pressure application.
> what now - suggest i have some kind of digital deformity and super-human
> strength so the result can be "ignored"? do the math on the indentation
> force. no, wait, /google/ for the math on the indentation force - it's
> been done for you. but i warn you, you'll be straying into retention
> force territory annan - you probably won't want to go there.


Oh, pull your head out of your ****, Beam. As I said at the time
(google for the post if you want), that was repeated on several
different bikes, one of which I checked repeatedly to see if this
embossing got more obvious over time. I don't think I reported it, but
I took one skewer and ramped it as tight as my padded hands could cope
with (far tighter than any recommendation) - still didn't emboss
through the virgin paint to the metal. These aren't exactly super
thick tough paint jobs we're talking about here, either.

So my actual, experimental evidence suggests that on new bikes you
don't have a metal to metal interface no matter what you do to the QR.
This substantially lowers the required pullout force.

Now if you've got a larger sample size, I'd love to hear it. Until
then I think I'm one of the only people who's even attempted actual,
unbiased experiments on this topic - ironically enough, something I
recall Beam complaining loudly about the lack of. Funny how he
complains even louder when things don't go his way.
 
Quoting Ed Pirrero <[email protected]>:
>David Damerell wrote:
>>Quoting Ed Pirrero <[email protected]>:
>>>G.T. wrote:
>>>>Wow, your mind works in mysterious ways.
>>>I understand that. In a world filled with emotional rhetoric and
>>>name-calling, I seek facts.

>>It must have been some other <[email protected]> who explicitly stated
>>they help with the name-calling, I suppose?

>Don't throw stones when your abode is made of glass.


I'm not lying about the name-calling. You are.

[Insert usual weasel here; even thought you said you seek facts in a word
filled with name-calling, you didn't actually mean to imply you weren't
calling names yourself. Oh, no.]

>>>I guess that's why I do science for a living.

>>In some way carefully hidden from Google. Of course. Funny how most of the
>>scientists I know are pretty keen to be visible on the Web...

>Logical fallacy: ad hominem.


Er, no. An ad hominem would be suggesting your argument is invalid because
there is no evidence to support your claim to be a scientist. I am not
doing that; I am merely observing that there is no such evidence when
ordinarily one would expect it to exist.

[However, you _are_ suggesting that your argument is valid because
(allegedly) you are a scientist. This, of course, is the logical fallacy
to which you allude.]
--
David Damerell <[email protected]> Kill the tomato!
Today is First Sunday, February - a weekend.
 
David Damerell wrote:
> Quoting Ed Pirrero <[email protected]>:
> >David Damerell wrote:
> >>Quoting Ed Pirrero <[email protected]>:
> >>>G.T. wrote:
> >>>>Wow, your mind works in mysterious ways.
> >>>I understand that. In a world filled with emotional rhetoric and
> >>>name-calling, I seek facts.
> >>It must have been some other <[email protected]> who explicitly stated
> >>they help with the name-calling, I suppose?

> >Don't throw stones when your abode is made of glass.

>
> I'm not lying about the name-calling. You are.


Hmm, I don't recall denying that I have done it. So how is it possible
to be lying?

> [Insert usual weasel here; even thought you said you seek facts in a word
> filled with name-calling, you didn't actually mean to imply you weren't
> calling names yourself. Oh, no.]


I actually do seek facts, until idiots such as yourself come along,
very late in the thread, not to offer additional facts, but to sling
arrows.

But hey, you're just getting off on button-pushing.

> >>>I guess that's why I do science for a living.
> >>In some way carefully hidden from Google. Of course. Funny how most of the
> >>scientists I know are pretty keen to be visible on the Web...

> >Logical fallacy: ad hominem.

>
> Er, no. An ad hominem would be suggesting your argument is invalid because
> there is no evidence to support your claim to be a scientist.


That's exactly what you're suggesting. Of course, not having the
stones to actually come out and say it.

You can try and weasel out of it - my quest for data is absolutely
valid, as are my concerns about James' approach. Now, if you have
something of value to offer, then I'm willing to discuss.

If not, ********. [Gratuitous insult]

E.P.
 
Johnny Walker wrote:

> oh, and since you obviously missed it countless times before, the
> reason for /not/ front mounting a caliper is FATIGUE. cast alloys
> such as those in forks and calipers ARE NOT GOOD IN TENSILE FATIGUE.
> that's a pretty fundamental omission from someone that seems to feel
> qualified to lecture on what comprises good engineering design.


Oh hogwash! Nearly all current disk brake calipers have at least one
of the two retaining bolts exerting tension on its attachment eye.
Besides, fork stanchions, to which these are attached, are loaded in
bending which naturally causes tension and compression about a neutral
axis. Stop generating this stream of specious argumentation and offer
something constructive.

Just in case you don't have the URL for Webster's Dictionary at hand:

Specious: 3 : having a false look of truth or genuineness

It seems you are competing for chief sophist of wreck.bike, from the
things you write.

Sohphist: 3 : a captious or fallacious reasoner

Jobst Brandt
 
Michael Press writes:

>> definitely be curious to see evidence that they do. ;-)


> From what you understand of the theory, consider this proposed
> experiment.


> Take a bicycle equipped with a disc caliper mounted on the back of
> the fork. Loosen the quick release clamp until it is barely
> engaged. Walk the bicycle at a brisk pace, then apply the front
> brake.


Hey! That's my experiment, except that I suggested it be done
statically by applying the brake while pushing the bicycle forward by
the bars. That demonstrates the effect adequately.

Up to now there has been no specious response to that test, although
it has been out there for months (since the beginning of the subject).

Jobst Brandt
 
Dave Wissenbach writes:

> When and if the time comes to replace the fork I'll purchase a
> replacement from a manufacturer who has made design changes which
> rectify the problem. (Marzocchi appears to be using a forward angle
> on some of their fork dropouts this year.)


Hold the phone! The primary problem is a reversing load that tends to
loosen a QR. That the load is in the wrong direction for conventional
dropouts Makes it doubly hazardous. The solution is to get rid of the
road-bicycle type QR and institute a reliable retention mechanism that
does not rely on friction... Or place the caliper ahead of the fork.

Jobst Brandt
 
[email protected] wrote:
> Michael Press writes:
>
> >> definitely be curious to see evidence that they do. ;-)

>
> > From what you understand of the theory, consider this proposed
> > experiment.

>
> > Take a bicycle equipped with a disc caliper mounted on the back of
> > the fork. Loosen the quick release clamp until it is barely
> > engaged. Walk the bicycle at a brisk pace, then apply the front
> > brake.

>
> Hey! That's my experiment, except that I suggested it be done
> statically by applying the brake while pushing the bicycle forward by
> the bars. That demonstrates the effect adequately.


And the only thing it shows is the thing everyone already agrees upon.

Is there anybody who actually believes that the ejection force doesn't
exist?

This experiment answers no other questions, verifies no calculations,
and is not instructive in what the actual forces are.

Facetious, or disingenous. At this late stage in the discussion,
that's all you're being.

E.P.
 
Old Crow writes:

>>> no, the over-center was not an original feature - the old straight
>>> lever campy qr's tighten all the way to the stop.


>> You should take one of those apart. The original design clearly
>> goes 'over center' to lock.


> i did. it functioned as i described. i wouldn't use it because of
> that.


That's too bad, because even without taking it apart the over center
feature is detectable both by inspection and manual action. I
wouldn't be riding those original QR's if that were not the case. You
are trying hard to avoid any credibility, if there was any.

Jobst Brandt
 
Andrew Muzi writes:

>>> Hey jim - found those BROKEN brake bolts yet?
>>> You've decided they are unsafe - show us the evidence...


>> i've told you before, answer my questions and i will. what are you
>> afraid of?


> 1.)The overwhelming bulk of brake center bolts have cut threads and


> 2.)failure is virtually unknown - even after being bent from hitting
> the downtube in a crash.


> Does anyone seriously dispute either statement?


> If I recall, Mr Beam asserted that brake bolts have rolled threads
> (which is a good idea, I suppose, but in the world we actually live
> in, they don't) and hasn't yet had either the opportunity to look at
> brake bolts closely or the grace to walk away from his hasty
> statement. Did I miss anything?


> I looked at vintage and modern brake bolts a few weeks ago but
> tonight I shot a photo of a brand new Campagnolo Chorus caliper:


> http://www.yellowjersey.org/photosfromthepast/CHRCALIP.JPG


> Note that in the profile shot, the thread is clearly smaller than
> (cut from ) the body of the bolt. Rolled threads are raised above
> the base diameter.


> OK, is this over yet?


Probably not. What doubters do not recognize is that the brake anchor
bolt on a typical side-pull brake has a boss that retains the return
spring and serves as a backing for the caliper arms against which they
tilt when braking. There is no reasonable and safe way to mount that
boss except to make it integral with the bolt. That is, the bolt is
machined from a rod that has the diameter of the boss. The thread
cannot be rolled because the shaft serves as a bearing for the
caliper. A rolled thread would not permit the parts to slide onto the
shaft unless the threads were a substantial size smaller which would
offer less strength than a cut thread of the shaft diameter.

Besides that, brake loads are not large, the major stress being
bending at the integral anchor boss that has a suitably radiused
transition to the shaft.

Jobst Brandt
 
Ed Pirrero writes:

>>>>>> The issue of loosening threaded fasteners is well-known in
>>>>>> mechanical engineering. Perhaps you think that the laws
>>>>>> governing such things are different for bicycles?


>>>>> Yes it is as are the methods of preventing it - and two of those
>>>>> methods are built into a standard QR. Perhaps you think those
>>>>> measures work everywhere in engineering except bicycles


>>>> Other brakes don't create an ejection force, and neither should
>>>> disk brakes. Simple as that.


>>> And there you have it. An *opinion*. Which is what most of this
>>> argument boils down to, in the end.


>>> Some force exists, and folks have opinions on how it should, or
>>> should not, be addressed. While opinions are interesting, and
>>> fodder for lengthy usenet discussions, they do not rise to the
>>> level of fact or data.


>>> The militant will vehemently disagree, of course. As always.


>> How about a practical test.


> [same non-data-producing "test" snipped]


Interesting. You cite all the exchanges above but choose to leave out
that with which you take issue. This strikes me as being largely
ingenuous.

Maybe you need some help in test citation:

# With a front disk brake equipped bicycle having the QR loose, apply
# the brake while pushing the bicycle forward by the bars. That
# demonstrates the effect adequately.

Is that too voluminous to include in your lengthy derision of same?

> While this test gives the antis a warm, fuzzy feeling all over, it
> doesn't generate any real data on what the forces actually are for
> the system. There is so much conjecture and so little real, actual,
> hard data, that it's hard to take the conjecture very seriously.


> Even for the vast array and abilities of the users of the current
> system, it appears quite effective, if for no other reason than the
> stunning lack of reported (not to say verified) injuries. I'm not
> even sure that they would even rise above the statistical noise. It
> would be nice to have actual data, such that the debate could be put
> to rest.


>> As I see it a proper solution could be a motorcycle type clamped
>> axle with a QR lever as the clamping element, making the wheel
>> manually exchangeable and functionally safe. This can be
>> accomplished in a way that even with the QR left open, the axle
>> will merely rattle in place but not separate with brake
>> application. For this, the through-axle would need a detent
>> (groove) into which a spring loaded ball could register in the home
>> position similar to indexing shift levers. QR levers at each fork
>> blade would securely clamp the axle. In fact, with a close fit,
>> only one end would require a closure lever.


> The QR20 axle system is close to this.


So?

> Maybe all forks will be that way in 10 years. But until the problem
> is backed with something more than a FBD and the opinions of some
> usenetters, it seems somewhat unlikely.


> Class action lawsuit, if one could round up a big enough class.


Oh, you want more severely injured bicyclists before changing anything
on a system that has obvious problems.

Jobst Brandt
 
[email protected] wrote:
> Ed Pirrero writes:
>
> >>>>>> The issue of loosening threaded fasteners is well-known in
> >>>>>> mechanical engineering. Perhaps you think that the laws
> >>>>>> governing such things are different for bicycles?

>
> >>>>> Yes it is as are the methods of preventing it - and two of those
> >>>>> methods are built into a standard QR. Perhaps you think those
> >>>>> measures work everywhere in engineering except bicycles

>
> >>>> Other brakes don't create an ejection force, and neither should
> >>>> disk brakes. Simple as that.

>
> >>> And there you have it. An *opinion*. Which is what most of this
> >>> argument boils down to, in the end.

>
> >>> Some force exists, and folks have opinions on how it should, or
> >>> should not, be addressed. While opinions are interesting, and
> >>> fodder for lengthy usenet discussions, they do not rise to the
> >>> level of fact or data.

>
> >>> The militant will vehemently disagree, of course. As always.

>
> >> How about a practical test.

>
> > [same non-data-producing "test" snipped]

>
> Interesting. You cite all the exchanges above but choose to leave out
> that with which you take issue.


No, not really interesting. It's not an informative or enlightening
test, nor is that the only example even in this thread of the test
being proposed.

Does this test show the magnitude of the forces involved? Does it show
the peak magnitude of the possible forces? Does it take into account
any of the potentially complicating factors that may have been
overlooked or even discounted up to now?

No? Then what does it show? Nothing that folks don't already all
agree on. So it's worthless.

"In other news, water is wet."

> Is that too voluminous to include in your lengthy derision of same?


Derision? Try and rein in your overactive imagination. If you were
interested in the complete answer to the questions posed, you would not
work so hard to avoid them.

> > The QR20 axle system is close to this.

>
> So?


The system you "designed" exists already. No need to re-invent it.

> > Maybe all forks will be that way in 10 years. But until the problem
> > is backed with something more than a FBD and the opinions of some
> > usenetters, it seems somewhat unlikely.

>
> > Class action lawsuit, if one could round up a big enough class.

>
> Oh, you want more severely injured bicyclists before changing anything
> on a system that has obvious problems.


Logical fallacy: strawman.

Can anyone one of you pro-redesign-it-now folks actually *not* resort
to juvenile tactics to make your points?

Stick to engineering. Your rhetorical skills are weak.

E.P.
 
Ed Pirrero writes:

>>>> definitely be curious to see evidence that they do. ;-)


>>> From what you understand of the theory, consider this proposed
>>> experiment.


>>> Take a bicycle equipped with a disc caliper mounted on the back of
>>> the fork. Loosen the quick release clamp until it is barely
>>> engaged. Walk the bicycle at a brisk pace, then apply the front
>>> brake.


>> Hey! That's my experiment, except that I suggested it be done
>> statically by applying the brake while pushing the bicycle forward
>> by the bars. That demonstrates the effect adequately.


> And the only thing it shows is the thing everyone already agrees
> upon.


> Is there anybody who actually believes that the ejection force
> doesn't exist?


I guess you haven't been following the argumentation on the subject
closely enough, but then that isn't easy, considering the volume
of rhetoric.

> This experiment answers no other questions, verifies no
> calculations, and is not instructive in what the actual forces are.


We have the calculations as well. That is one you should have read,
considering it is your principal claim.

> Facetious, or disingenous. At this late stage in the discussion,
> that's all you're being.


You'll have to put more body on that to make it have meaning.

Jobst Brandt