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Cannondale's tests of disks and QRs



 
 
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  #181  
Old October 2nd 04, 09:25 AM
Dave Kahn
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On 30 Sep 2004 15:46:49 +0100, Ambrose Nankivell
wrote:

(Dave Kahn) writes:

Tom Sherman wrote in message ...


The word "teh" appears seven times. What does "teh" mean?


I would have thought that anyone with the intellectual equipment to
follow, or even read through, Ian's argument would have had little
trouble with such a trivial anagram.


OK: The word "het" appears seven times. What does "het" mean?


Buggered if I know. :-)

--
Dave...

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  #182  
Old October 2nd 04, 10:35 AM
Simon Brooke
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in message , Dave Kahn
') wrote:

On 30 Sep 2004 15:46:49 +0100, Ambrose Nankivell
wrote:

(Dave Kahn) writes:

Tom Sherman wrote in message
...


The word "teh" appears seven times. What does "teh" mean?

I would have thought that anyone with the intellectual equipment to
follow, or even read through, Ian's argument would have had little
trouble with such a trivial anagram.


OK: The word "het" appears seven times. What does "het" mean?


Buggered if I know. :-)


An abbreviation of hetero, meaning 'different from' (this is not an ad
homonym comment).

--
(Simon Brooke) http://www.jasmine.org.uk/~simon/
Das Internet is nicht fuer gefingerclicken und giffengrabben... Ist
nicht fuer gewerken bei das dumpkopfen. Das mausklicken sichtseeren
keepen das bandwit-spewin hans in das pockets muss; relaxen und
watchen das cursorblinken. -- quoted from the jargon file

  #183  
Old October 2nd 04, 10:55 AM
Just zis Guy, you know?
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On Sat, 02 Oct 2004 05:28:26 GMT, SuperSlinky wrote
in message :

All the engineering types here are trying to outdo each other in techno-
babble, but while this may impress the gullible, what I see above is
only a small part of the big picture. Let's assume for a moment that the
ejection forces exceed or are unacceptably close to restraining forces.
How does a skewer that starts sliding down the dropout get past the
ubiquitous retention lips?


By coming undone. Do try to keep up at the back there! And what if
the wheel stays in the fork, but slips sideways and jams solid?

Your faith in lawyer lips as the solution to all problems is touching,
if misplaced. If the problem is as unlikely as you claim, how come
Cannondale designed their test to steer well clear of the kinds of
forces James has documented, i.e. heavy repeated braking on rough
ground?

Guy
--
May contain traces of irony. Contents liable to settle after posting.
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  #184  
Old October 2nd 04, 01:41 PM
Ian Smith
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On Sat, 02 Oct 2004 05:28:26 GMT, SuperSlinky wrote:
Ian Smith said...

It's not me that's seeking to prove anything by estimating available
restraint forces - it's you. It's your argument that's in need of
defence, so having pointed out all these things wrong with it, it's
not really down to me to defend it. If, of course, you can't defend
your argument - can't explain why it's valid to assume serration
orientation etc. - we can simply drop your claim that there's 5000N
retsraining force available, and return to consideration of why teh
manufacturers don't want to think about wheel ejection, when it is
evidently a real issue.


All the engineering types here are trying to outdo each other in techno-
babble, but while this may impress the gullible,


Well obviously if super-slinky doesn't understand it, it must just be
irrelevant babble. Oh yes.

only a small part of the big picture. Let's assume for a moment that the
ejection forces exceed or are unacceptably close to restraining forces.


Which is the limit of teh point I was making.

I was addressing the SPECIFIC point made by one poster that it can't
be a problem because the pull-out resistnace is massively greater than
any ejection force. I was demonstrating PURELY that this 'because' is
wrong.

I was doing nothing more, so why criticise what I did for going no
further? I didn't solve world peace or eradicate hunger either, but
that in no way reduces the accuracy of what I did or said. Why should
it?

it either stops or blows through the retention lips. Correct me if I'm
wrong, but I haven't heard anyone claim that the retention lips are
going to give way easily.


But interestingly, teh force to shear the retention lip would be
rather less than the 5000N that was presented as the cconservative
estimate of teh force required to shift the axle, because the argument
presented then _does_ make sense, but with a reduced area sheared.

I'd then have to wonder why retention lips are designed for a small
fraction of teh force that's conservatively generated from a QR.

problem that will require the immediate attention of the rider. Where
are all the reports of these partial failures? For every ejection we
should see even more partial failures, yet the cycling community does
not offer any examples of them ever occurring,


Well, you're evidently looking in teh wrong places, since I have seen
a reasonable number of reports.

regards, Ian SMith
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  #185  
Old October 6th 04, 05:40 AM
jim beam
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James Annan wrote:
David Martin wrote:


Maybe it is time to find a pair of forks, a standard q/r hub and a
machine
that can do a lot of pulling and measure it..



Um....this has actually been done, systematically and fairly thoroughly.
There's a published test report linked from my website (surprise).

The pullout resistance achieved in real life seem to generally be way
below jim beam's theoretical calculation (which, to be blunt, completely
misses the point, irrespective of whether or not his figure can be
achieved in some circumstances).

James


um, this test report
http://www.engr.ukans.edu/%7Ektl/bicycle/QRReport1.pdf
is really rather weak.

it spends an inordinate amount of time doing 10th grade science class
testing on clamping force, merely a function of cam displacement - even
to the extent of bothering to see whether fork material could affect q/r
lever closure force [sic] - but then goes on to ignore the elephant in
the room, the effect of different fork materials and axle end serrations
on pull-out force. it does briefly touch on "embossing" of fork ends by
serrated axle faces, but doesn't bother to investigate it in any detail.
critical details missed in my opinion.

maybe that's why it was cited?

  #186  
Old October 6th 04, 05:44 AM
jim beam
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James Annan wrote:
SuperSlinky wrote:

Where are all the reports of these partial failures? For every
ejection we should see even more partial failures, yet the cycling
community does not offer any examples of them ever occurring,



It's deja vu all over again!

http://tinyurl.com/5s5uo

A couple of those singletrackworld URLs are now out of date as the posts
have been archived, "f=2" needs to be changed to "f=8" in the first two.
Not that SuperSlinky is any more likely to read them this time round
than he did last time, but others may be interested.

This is how the manufacturers respond when someone reports a problem to
them:

http://www.ne.jp/asahi/julesandjames...se/denial.html


Make no mistake, this is all about scare-mongering, ego and emotion.



Um...and what is your motivation, SuperSlinky?

Anyone who doubts this should take note that the question has been
looked at by scientists, and not the ones on Usenet.



Yeah, sure, these great "scientists" who are obviously superior
intellects to any of us - that's why they work in the high-prestige and
high-pay bike industry, after all.

The only publically available research from these "scientists" is the
Cannondale test. What do you think of that? Can you think any "reasons
to believe anything is missing or over constrained in this test"?

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


If not, perhaps you might like to think of applying for a job there. I'm
sure they could use someone of your calibre.

James


exactly how is such petty sniping advancing your argument other than
disgusting people to the extent of withdrawing? just because people are
sufficiently adult to not rise to your bait does not make your argument
more accurate - though you seem to misinterpret silence as their
acquiescence.

 




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