Carlton Reid on QR safety

[[email protected]]

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

 

[James Annan]

jim beam wrote:

> James Annan wrote:
>
>> jim beam wrote:
>>
>>> James Annan wrote:
>>>
>>>> jim beam wrote:
>>>>
>>>>
>>>>> James Annan wrote:
>>>>
>>>>
>>>>
>>>>>> http://www.ne.jp/asahi/julesandjames/home/disk_and_quick_release/QRReport1.pdf
>>>>>>
>>>>>>
>>>>>>
>>>>>> The Howat numbers are an order of magnitude lower than your risible
>>>>>> "calculation" of the retention ability of a QR that you made up
>>>>>> previously. They are similar to (often lower than) the estimated
>>>>>> ejection force.
>>>>>
>>>>>
>>>>> they're lower if the qr is not tightened sufficiently [go figure -
>>>>> obviously it would take a climatologist to work that one out] and
>>>>> substantially higher when tightened correctly.
>>>>
>>>>
>>>>
>>>> Please define "tightened correctly",
>>>
>>>
>>> i refer you to your favorite paper, howat. or failing that, read
>>> manufacturer instructions some time.
>>>
>>>
>>>> and describe how a rider can
>>>> achieve this with no tools.
>>>
>>>
>>> read the shimano instructions. you /do/ read instructions don't you
>>> annan?
>>
>>
>>
>> Yes, I do, which is why I asked you what you meant. And of course you
>> ducked the question, because you are making this up as you go along,
>> ducking and weaving as you go.
>
>
> eh? you say: "describe how a rider can achieve this with no tools", i
> quote the manufacturer instructions verbatim, and you start bleating
> that i'm "ducking & weaving". holy **** annan, you got some serious
> reality distortion issues going on there guy.
>
>>
>> In fact, it is clear that the manufacturers' instructions do not
>> guarantee that the QR will withstand a disk brake force. For starters,
>> they do not instruct the user to chip all the paint off his fork
>> dropouts.
>
>
> bwah bwah bwah. what other goal posts do you want to move?
>
>>
>>
>>>> You may find it helpful to refer to
>>>> instructions provided by any QR manufacturer, or bike manufacturer, or
>>>> retailer. Note that your method to ensure that the skewer is "tightened
>>>> correctly" should guard against overtightening, as well as
>>>> undertightening.
>>>
>>>
>>> hmm, so when, in print, a manufacturer instructs a user to tighten "with
>>> as much strength as possible", do you find that equivocal in any way?
>>
>>
>>
>> I find it worrying that any manufacturer would think it appropriate to
>> give such instructions.
>
>
> eh? which way do you want it annan?
>
>>
>>
>>> do you seriously think you can break a qr by hand???
>>
>>
>>
>> That comment is particularly good timing, coming as it does just a few
>> days after someone in a different thread mentions a case of just this
>> happening. Are you actually claiming that it is not possible to
>> overtighten a QR?
>>
>> First google hit:
>>
>> -----
>> OVERTIGHTENING THE QUICK RELEASE MECHANISM MAY DAMAGE THE QUICK RELEASE
>> ASSEMBLY. FOR FURTHER INFORMATION ON CORRECT ADJUSTMENT OF THE QUICK
>> RELEASE TENSION, SEE ADDITIONAL INFORMATION BELOW:
>>
>> To properly close the quick release mechanism requires between 15
>> and 45 pounds of force. [55 to 200 Newton]. If the required closing
>> force is greater than 45 pounds, open the lever and loosen the
>> mechanism adjusting nut. Close the lever again.
>> -----
>>
>> I know that Salsa give an explicit range of 24-30 pounds of force on
>> the QR lever.
>>
>> So, how about that "correctly tightened" thing. Care to try again?
>>
>> James
>>
>
> that's an open cam skewer annan. we've discussed the failings of that
> design before. oh, wait, you want to change the rules in the middle of
> the game? sorry, my bad.

Oh, so you agree that these skewers are not safe? That's a start.

James
--
James Annan
see web pages for email
http://www.ne.jp/asahi/julesandjames/home/
http://julesandjames.blogspot.com/

 

[James Annan]

Ed Pirrero wrote:

> Since there seem to be fewer incidents than predicted from the
> hypothesis,

How many incidents are predicted?

James
--
James Annan
see web pages for email
http://www.ne.jp/asahi/julesandjames/home/
http://julesandjames.blogspot.com/

 

[Boyle M. Owl]

Michael Press wrote:

> 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.

I've sat here and read this thread and watched you repeatedly make this
same request for an "experiment". Your first ideas to have someone ride
a bicycle with the front QR "barely engaged" to 25MPH was not only
_ludicrous_ but it was also _dancing with the liability boogyeman_. I
could only imagine what might have happened if someone did what you
requested and hurt himself. Using your logic, they should have rightly
sued _you_ along with suing the fork manufacturer.

Talk about hoisting oneself upon one's own petard.

You're asking for people to use a QR _improperly_ to prove some sort of
point about pullout force. Well, the only point is upon your head. If
you don't wear a hat, it won't show.

IOW, you're just a mere troll. Git along little troll, git along, git
along...*fr0h slap!*

And here is your punishment, to be tortured by Safety Dance, but
reworded to _my_ lyrics.

S-s-s-s A-a-a-a F-f-f-f E-e-e-e T-t-t-t Y-y-y-y
Safety, troll!

I can troll if I want to
I can leave your posts behind
'Cause your posts don't troll and if they don't troll
Well they're no posts of mine
I say, we can troll where we want to
A goatse they can always find
And I can act like we come from the GNAA
Leave the moderations far behind
And we can troll.

--
BMO

 

[Ed Pirrero]

James Annan wrote:
> Ed Pirrero wrote:
>
> > Since there seem to be fewer incidents than predicted from the
> > hypothesis,
>
> How many incidents are predicted?

Since, as you say, the force purported to exceed the ISO minimum, the
number should be greater than zero.

State clearly whether or not this prediction is implied. If it is not
implied, then all this is an exercise in buffoonery. If it is implied,
then incidents of ejections should be greater than zero. *Especially*
considering the volume of disk brakes in use.

E.P.

 

[James Annan]

Ed Pirrero wrote:

> James Annan wrote:
>
>>Ed Pirrero wrote:
>>
>>
>>>Since there seem to be fewer incidents than predicted from the
>>>hypothesis,
>>
>>How many incidents are predicted?
>
>
> Since, as you say, the force purported to exceed the ISO minimum, the
> number should be greater than zero.
>
> State clearly whether or not this prediction is implied. If it is not
> implied, then all this is an exercise in buffoonery. If it is implied,
> then incidents of ejections should be greater than zero. *Especially*
> considering the volume of disk brakes in use.

There have been many incidents at varying levels of severity.

Someone posted earlier in this thread about how their QR regularly
slipped in the dropouts. Do you think he was lying, or incompetent? Or
are you just going to insist this was not "verified", according to some
standard of "verification" that you cannot articulate.

James
--
James Annan
see web pages for email
http://www.ne.jp/asahi/julesandjames/home/
http://julesandjames.blogspot.com/

 

[Boyle M. Owl]

[email protected] wrote:

> 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.

Hey Jobst, go crack open a Machinery's Handbook (whatever edition you
may have - I've got 23 and 27) and look at rolled thread strength as
opposed to cut thread strentgh, and get back to me, OK? You may have a
PhD in physics, but neither a PhD nor educated opinion is any substitute
for empirical results.

Also, your gedankenexperiment saying that cut threads are the only ones
possible because the brake hardware couldn't be pushed on to the bolt is
bogus. What happens, in actuality, is that the diameter of the
unthreaded screw blank is smaller than the finished ID so that the metal
can flow up to the finished diameter for the crest (major diameter) of
the thread.

> substantial size smaller which would
> offer less strength than a cut thread of the shaft diameter.

Bzzt - wrong. Whether a thread is rolled or threaded, the minor, major,
and pitch diameters are _identical_.

But not only that:

All rolled threads are stronger than cut threads due to the fact that
the tooling does not cut the grain of the material, but instead
_deforms_ the grain instead. If you have a malleable material (like
1018 cold-rolled as opposed to a work-hardening material like D-2 tool
steel), your best bet is to use a rolled thread _every_time_.

--
BMO

 

[Tim McNamara]

jim beam <[email protected]> writes:

> James Annan wrote:
>> Ed Pirrero wrote:
>>
>>>James Annan wrote:
>>>
>>>>Ed Pirrero wrote:
>>>>
>>>>>Zero
>>>>>credibility.
>>>>
>>>>Yes, that seems a fair summary of your scientific background.
>>>
>>>And here we have a concise summary of James Annan. Takes the data
>>>that fits his view, and rejects the rest.
>>>
>>>To real scientists, this is called "junk science".
>>>
>> How would you know what a "real scientist" would think? Have you
>> ever met one? James
>>
> he is one annan. he's all over the web if you know who you're
> looking for.

He's all over Usenet, anyway, but that's only proof of an Internet
connection. I find nothing by him that is scientific or scholarly,
certainly not in this newsgroup. Is he just another sock puppet of
yours, perhaps?

 

[Boyle M. Owl]

Boyle M. Owl wrote:

> Bzzt - wrong. Whether a thread is rolled or threaded, the minor, major,
> and pitch diameters are _identical_.

Oh, and I forgot to add this, that the calculated tensile strength of a
threaded rod is based upon the minor diameter, and since a threaded rod
which is rolled has the same minor diameter of a cut threaded rod, then
the diameter used for calculating the tensile strength is the same for both.

--
BMO

 

[Tim McNamara]

"Boyle M. Owl" <[email protected]> writes:

Oh, look, more sock puppets.

 

[Boyle M. Owl]

Tim McNamara wrote:

> "Boyle M. Owl" <[email protected]> writes:
>
> Oh, look, more sock puppets.

Moi? A sock puppet?

I've been accused of a lot of stuff, but this is a first.

Just whose sockpuppet do you suppose I am?

Maybe you're projecting.

--
BMO

 

[Tim McNamara]

jim beam <[email protected]> writes:

> Tim McNamara wrote:
> <snip drivel>
>> I see. And that situation is insurmountable? The designers are
>> incompetent to deal with that? Good heavens. Might as well go
>> back to V-brakes, dude. Oh wait, those are mounted on the front
>> too- no doubt there are millions of them being ripped off of forks
>> even as we speak.
>
> oh dear. sorry tim, zero points. do the math on the force at the
> brake bosses compared to a disk tab. look at the comparative size
> differences too and use that to estimate stress. then look at an
> s-n chart.

LOL. So, the forces on a rim brake aren't enough to cause the cast
aluminum mounts or the brake bolts to fail, but are high enough to
cause the mounts and/or the bolts to fail on a disk brake. But then
again, you claim that the forces generated by a disk brake are not
enough to cause a skewer to slip or even fail, despite the skewer
being only slightly larger than half as thick as the mounting bolts
holding the disk brake caliper on to the fork- and there being only
one skewer versus two brakes.

jim, keep digging- you're almost to China!

 

[Tim McNamara]

A Muzi <[email protected]> writes:

> Can we drop this now?

Not until you admit that jim beam is right. That's what this is
about, after all.

 

[Boyle M. Owl]

Boyle M. Owl wrote:

> is smaller than the finished ID so that the metal

That should be "finished OD"

--
BMO

 

[Tim McNamara]

"Clive George" <[email protected]> writes:

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

Wow. Now that's gorram funny!

 

[James Annan]

Clive George wrote:

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

Rumbled!

James
--
James Annan
see web pages for email
http://www.ne.jp/asahi/julesandjames/home/
http://julesandjames.blogspot.com/

 

[Tim McNamara]

Tim McNamara <[email protected]> writes:

> jim beam <[email protected]> writes:
>
>> Tim McNamara wrote:
>> <snip drivel>
>>> I see. And that situation is insurmountable? The designers are
>>> incompetent to deal with that? Good heavens. Might as well go
>>> back to V-brakes, dude. Oh wait, those are mounted on the front
>>> too- no doubt there are millions of them being ripped off of forks
>>> even as we speak.
>>
>> oh dear. sorry tim, zero points. do the math on the force at the
>> brake bosses compared to a disk tab. look at the comparative size
>> differences too and use that to estimate stress. then look at an
>> s-n chart.

I should proofread a little more carefully.

> LOL. So, the forces on a rim brake aren't enough to cause the cast
> aluminum mounts or the brake bolts to fail, but are high enough to
> cause the mounts and/or the bolts to fail on a disk brake.

Not actually disagreeing with you on this, even though it reads like
it. The intent was to highlight that you do admit the high forces
generated at the dropout.

> But then again, you claim that the forces generated by a disk brake
> are not enough to cause a skewer to slip or even fail, despite the
> skewer being only slightly larger than half as thick as the mounting
> bolts holding the disk brake caliper on to the fork- and there being
> only one skewer versus two brakes.

Two bolts, not two brakes. Doh. Pointing out the incongruity of your
claim that one skinny QR skewer is stronger than two bolts nearly
twice the diameter of the skewer.

 

[Benjamin Lewis]

jim beam wrote:

> Benjamin Lewis wrote:
>> jim beam wrote:
>>
>>> Tim McNamara wrote:
>>> <snip drivel>
>>>
>>>> I see. And that situation is insurmountable? The designers are
>>>> incompetent to deal with that? Good heavens. Might as well go back
>>>> to V-brakes, dude. Oh wait, those are mounted on the front too- no
>>>> doubt there are millions of them being ripped off of forks even as we
>>>> speak.
>>>
>>> oh dear. sorry tim, zero points. do the math on the force at the
>>> brake bosses compared to a disk tab. look at the comparative size
>>> differences too and use that to estimate stress.
>> How can we "look at the size differences" on a non-existent design?
>
> eh? disk tabs and brake bosses exist. do we have a communication
> problem?

Disk tabs on front mounted calipers do not exist. If they did, an
intelligent designer would make them larger.

>> That stress is greater on rear mounted disk brake tabs than on
>> cantilever bosses is true, but irrelevant.
>
> it's /highly/ relevant in fatigue!

The stress on rear-mounted disk tabs is irrelevant in a discussion of
front-mounted disk tabs.

--
Benjamin Lewis

Now is the time for all good men to come to.
-- Walt Kelly

 

[Michael Press]

In article <[email protected]>,
[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.
>
> 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).

Hey! I first proposed that the experimenter loosen the QR
to just tight, mount, run up to 25 km / hr, then apply the
front brake strongly. Upon reading your version, I
modified my original proposal.

--
Michael Press

 

[Benjamin Lewis]

jim beam wrote:

> 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.

Did "jim beam" really write this, or is it an attempt by a forger to
further disparage his character?

--
Benjamin Lewis

Now is the time for all good men to come to.
-- Walt Kelly