"Actually you are the first person to bring up this issue"

(Jonesy) writes:

James Annan wrote in message ...

So there you have it. At this rate, by the time next year's
complaint comes in, they will presumably have forgotten this first
one. How convenient for them. Those who thought that it wouldn't do
to kick up a fuss because the poor manufacturers were doing their
best, may wish to re-examine their approach. Or else studiously
ignore this post in the vain hope that the problem will go away.

Assuming, of course, that there actually *is* a problem.

There's no doubt that there is a problem. The only question is how
often it happens.

It'll be nice to see all that wonderful, properly-controlled data
from the laboratory testing.

Think of it like Microsoft Windows: *you* are the testing lab.

When that comes out for public view, then we'll all be able to avoid
drawing conclusions from anecdotal evidence.

It would be nice to have something other than a detailed engineering
analysis quantifying the force and magnitude of the ejection force
created by front disk brakes mounted behind the shock fork leg, paired
with a detailed engineering analysis of how the QR can be unscrewed by
the repeated ejection force resulting from normal use. Ummm, oh yeah,
that's *not* anecdotal evidence. That's objective evidence, which the
anecdotes (including video of a front wheel ejection) serve to
support.

The fact that the brake creates an ejection force at all is evidence
of the design flaw. It's really quite simple. The arguments against
this citing improper use of a QR are just desperate smoke and mirror
attempts to obfuscate.

Tim McNamara:

BenS writes:

Putting the caliper on the front of the fork would probably lead to
it ripping off it's mounting.

How do you figure? The forces on the mounting bosses on the fork leg
would be the same as they are with the current design.

BenS is probably referring to the post type mounts (Manitou), where the
axes of the mounting bolts are parallel to the plane of the rotor. If a
caliper with this type of mount is placed in front of the fork, the
bolts are going to take the caliper braking load in tension (not a good
idea in general), whereas if the caliper is behind the fork, it is the
mounting posts that take up the load (and in compression), the bolts
serving merely to fix the caliper in place.

Of course all these don't matter to IS mounts, where the mounting bolts
lie perpendicular to the rotor plane.

Tim McNamara:

Ummm, oh yeah,
that's *not* anecdotal evidence. That's objective evidence, which the
anecdotes (including video of a front wheel ejection) serve to
support.

You need to clarify that. Where is this video of a front wheel ejection
caused by the application of a disc brake? There has been the video of
a loose QR causing a wheel to come off the fork when the rider tried to
lift the handlebar while riding; you're not referring to that?

"Tim McNamara" wrote in message
...
See, that's the point. The brake should be designed so that it
*can't* force the wheel out of the dropouts, even if the QR is left
completely loose. It's a design flaw, an epic design flaw that will
cost some manufacturer a *lot* of money in court some day. No other
current brake design that I'm aware of puts an ejection force into
the wheel in normal operation, but front disk brakes do.

I'd have thought angling the drop-out so it faces forward would prevent the
axle rotating out if the pads are the pivot point.
I'm still trying to think of any negative implications from doing this as it
seems too easy.
Being cynical a non-mechanical implication would be manufacturers seen to be
fixing a problem they deny exists therefore admitting the potential problem
after the fact and leaving the industry wide open to litigation.
--
Regards,
Pete

in message wsN6c.16296$Cf3.2864@lakeread01, tcmedara
') wrote:

James Annan wrote:
"Frobnitz" wrote in message
...

Have you contacted someone like Watchdog (UK consumer affairs
program, for the non-UK readers on the x-post) to see if they are
interested.

No, I don't think there is any point in that. Firstly, it doesn't
affect me directly, and secondly, they are hardly going to take a
complaint seriously that has only ever been noticed by one rider (and
he didn't even have a crash or anything, it's just that his wheel
won't stay put). Since it's already been cleared by the CPSC, there
is obviously no design problem and I guess I must have made the whole
thing up. It was quite a hassle making all the fake user accounts on
singletrackworld:

http://www.singletrackworld.com/foru...34406&t=933851

and just to make it seem more authentic I forged this review and
hacked into Marin's site:

http://www.marin.co.uk/marin-2004/reviews.php?ID=47

LOL. While I think you are an obsessed quasi-religious zealot, that's
not why I'm going to goof on you.....

*Dumabass,*Frobnitz*was**supporting*you**!

Merkins. They just don't do irony, do they? Something to do with only
having senses of humor, not of humour. There's a lot goes missing with
that second 'u'.

Mind you, of course, most of them wouldn't recognise humour of any sort
if it fell on them in a thunderstorm.

Simon, generally phlegmatic, but occasionally sanguine.

PS Oh, and it was the _philosophers'_ stone.

--
(Simon Brooke) http://www.jasmine.org.uk/~simon/

;; Women are from Venus. Men are from Mars. Lusers are from Uranus.

in message ,
') wrote:

Zog The Undeniable wrote:

I'm pretty sure some manufacturers are now starting to put the disc
on
the RH side of the fork. It's certainly an accepted problem.

Or you can just turn the QR around so the lever is on the right side.

Or you could fill your bathtub with brightly coloured machine tools,
whilst intoning in a cod French accent 'this is not a pipe'.

All things are possible.

But I don't see what it has to do with solving the brake ejection
problem.

Simon, rides a Lefty, doesn't have a problem.

--
(Simon Brooke) http://www.jasmine.org.uk/~simon/

;; MS Windows: A thirty-two bit extension ... to a sixteen bit
;; patch to an eight bit operating system originally coded for a
;; four bit microprocessor and sold by a two-bit company that
;; can't stand one bit of competition -- anonymous

The bottom line here is not whether or not this issue is truthful, but how
and why it happens. I for one would like to know what the circumstances are
in each case that may trigger it.

As I've said previously, we ride a variety of singletrack and downhills
here, and the one time my QR let me down was traceable to my own fault.
After I tightened it up it didn't happen again the entire day. That was two
years ago and Blue Mountain. We had stopped off on the way back from
somewhere else and I happen to have the XC rig in the car. Everyone else was
riding FS freeride or DH bikes. I did the main ski run about 15 times that
afternoon...most of them "After" the QR came undone.

So the question is this: in each case where the problem occured, what were
the conditions? was it human error, or part failure?

"S o r n i" wrote:

Richard Bates wrote:
On Fri, 19 Mar 2004 11:37:22 -0500, in
, Sheldon Brown
wrote:

Sheldon "Insert Nickname Here" Brown

Is this a competition?

Umm, if it is you lose.

Don't pick "party doll"...

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $695 ti frame

"Peter B" writes:

"Tim McNamara" wrote in message
...

See, that's the point. The brake should be designed so that it
*can't* force the wheel out of the dropouts, even if the QR is left
completely loose. It's a design flaw, an epic design flaw that
will cost some manufacturer a *lot* of money in court some day. No
other current brake design that I'm aware of puts an ejection force
into the wheel in normal operation, but front disk brakes do.

I'd have thought angling the drop-out so it faces forward would
prevent the axle rotating out if the pads are the pivot point. I'm
still trying to think of any negative implications from doing this
as it seems too easy.

Changing the dropout angle or created enclosed dropouts like
motorcycles use would be one solution.

Being cynical a non-mechanical implication would be manufacturers
seen to be fixing a problem they deny exists therefore admitting the
potential problem after the fact and leaving the industry wide open
to litigation.

Their lawyers may have told them exactly that. A much better
strategy- from the lawyers' perspective of course- is to sit back and
wait for the injury lawsuits to happen. Since this design flaw has
been publicly discussed and acknowledged by well-known engineers and
by trade industry magazines, there is already grounds for litigation
to be considered.

Jose Rizal writes:

Tim McNamara:

BenS writes:

Putting the caliper on the front of the fork would probably lead
to it ripping off it's mounting.

How do you figure? The forces on the mounting bosses on the fork
leg would be the same as they are with the current design.

BenS is probably referring to the post type mounts (Manitou), where
the axes of the mounting bolts are parallel to the plane of the
rotor. If a caliper with this type of mount is placed in front of
the fork, the bolts are going to take the caliper braking load in
tension (not a good idea in general), whereas if the caliper is
behind the fork, it is the mounting posts that take up the load (and
in compression), the bolts serving merely to fix the caliper in
place.

Hmm. Thanks for clarifying this.

Of course all these don't matter to IS mounts, where the mounting
bolts lie perpendicular to the rotor plane.

Which make sense.