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



Mark Hickey <[email protected]> wrote in message news:<[email protected]>...
> [email protected] (Gary Young) wrote:
>
> >Mark Hickey <[email protected]> wrote in message
> >news:<[email protected]>...
> >> [email protected] (Gary Young) wrote:
> >>
> >> <snip>
> >> >But your attitude seems to be, we could lift a finger,
> >> >but we don't want to spend the money. Better that our
> >> >customers should pay the price for our stupidity.
> >> >Isn't that what you're saying? -- we could fix the
> >> >problem, but we won't. The only costs will be born by
> >> >someone else. We don't mind killing off a few
> >> >customers as long as it doesn't hurt our bottom line.
> <snip>
> >> >I'm quite surprised to see you pursue this line. All I
> >> >can say is that if this is your idea of customer
> >> >service, then I'll never buy one of your frames.
> >>
> >> Your (il)logical conclusions and inability to
> >> understand my position are astonishing. You really
> >> "don't get it", do you?
> >
> >Well, I should have been more temporate, for civility's
> >sake. Nonetheless, I think your position is contrary to
> >the law and morally obtuse. I find it troubling that you
> >haven't responded to a question I've posed a couple of
> >times: does the industry have a duty to warn its
> >customers about this problem?
>
> My "position" is that the manufacturers and CPSC probably
> don't think there IS a problem, and I'd like to see that
> remedied by collecting some data that might influence them
> (assuming of course that it shows there IS a problem).
>
> And FWIW, I don't have a "position" on how the rest of the
> industry handles potential liability. I have observations,
> which I shared and you subsequently ascribed to springing
> from my own moral code.
>
> Does the industry have a duty to warn customers NOW? I
> don't know... it all depends on how compelling the data
> they have is. I have no problem at all believing the data
> they have right now doesn't compel them to do an expensive
> recall / or to scare existing customers. I say that
> because (as I've said about a hundred times now...)
> they've all heard about skewers spontaneously unscrewing
> themselves, and a few reports of this happening to
> customers with disc brakes won't stand out as anything
> particularly unusual, barring more data.
>
I have seen this kind of "filtering effect" at work in other
contexts. For instance, years ago I was prescribed a
medication that had a rather disagreeable side effect for
me. I went to my doctor, he consulted his physicians desk
reference, told me, "No one has reported that side effect,"
and suggested, ever so gently, that it was all in my head.
Much later I read an article about the medication that
mentioned that side effect.

I don't think the doctor was at fault, or even the
manufacturer of the medication. I suspect that when the
manufacturer did its initial run of tests, it drew up a list
of side effects that were prevalent to show up in their
trials. Unfortunately, afterwards such a list can function
as a filter excluding other valid reports of side effects.

But even in that case, my doctor did something about the
situation -- switching me to another medication.

Furthermore, I don't think such a filtering effect is at
work here. Let's look at the lawyer from Trek as an example.
I find it hard to believe that a lawyer contacted by the
trade press about this problem would simply write it off as
the usual operator error, particularly after he's informed
that it's confined to disc-brake forks. If he went to one of
the engineers at Trek, he would have been told that this is
a different sort of claim and that it merits further study.
If he's a competent attorney, he would know that it's Trek's
duty to look into it or at the very least, pressure the fork
suppliers to look into it.

I suppose it's possible that industry lawyers are stone cold
stupid, but I'm not sure that matters. The tort system
punishes stupidity as well as venality.

I suspect that the industry is hoping there are no claims
until the problem can be addressed quietly.

Furthermore, given the evidence that's already been brought
to light, I don't think the studies you propose would do any
good. I'm not suggesting such studies would necessarily have
no scientific validity, but I suspect that if an industry
lawyer doesn't think that the opinion of a respected
engineer like Jobst is reason enough to be worried, he's not
going to change his mind because a bunch of guys on usenet
conducted experiments in their garages. Such a study would
have so little credibility (from a lawyer's perspective)
that it would not be a prod to action.
 
Simon Brooke <[email protected]> wrote

> I think one of the things that's going on here is that
> people who ride road bikes a lot are speculating about
> what it's like to ride off-road.

This friend speaks my mind.

- Tony
 
[email protected] wrote:
>
>
> Let's get the caliper in the right place!
>

Right place for what? It might reverse the ejection force
into a holding in force but OTOH the caliper is out front
where it is much more susceptible to damage and to getting
the mounting tabs bent/strained by hitting things. The
mounts would also be under tension under braking, rather
than compression which has an increased chance of failure.
Specialized have already had a recall for mounting tab
failures. Don't simply replace one problem with another and
think through all the failure modes of a proposed solution
before implementing it - Design Control 101.

Tony
 
Tony Raven writes:

>>>> If you consider forks without offset at the dropout
>>>> end, as they are commonly made today, where offset is
>>>> achieved at the fork crown, No change other than
>>>> placing the mounting lugs for the disc brake caliper on
>>>> the front side is required. I think the same caliper
>>>> would be adequate for most brands with the distance
>>>> between caliper and fork leg remaining as it is today.
>>>> This requires a new fork strut anyway.

>>> It might even be possible to simply swap the left and
>>> right fork lowers. Sometimes one sees bikes where the
>>> forks have been installed backwards... usually on eBay.

>>>> How long will it take to get the disc caliper ahead of
>>>> the fork leg?

>>> I wouldn't be surprised to see different wheel
>>> attachment instead. There are already various quick(ish)
>>> release 20mm systems that seem little more trouble than
>>> a QR with retention lips. That can also be sold as an
>>> upgrade rather than merely a bug-fix. And you get to buy
>>> a new shiny hub too!

>> Well that won't do as I already mentioned. The reversing
>> load from braking and bouncing on the road makes anything
>> but a conical "lug nut" ineffective to reliably prevent
>> loosening.

>> Let's get the caliper in the right place!

> Right place for what?

The right place to resolve the hazards that have been under
discussion in this thread for more than 500 replies.

> It might reverse the ejection force into a holding in
> force but OTOH the caliper is out front where it is much
> more susceptible to damage and to getting the mounting
> tabs bent/strained by hitting things.

Yes, and the moon may yet be made of green cheese. This is
grasping at straws to obscure the issue when all else fails.
What sort of damage do you foresee for a metal brake caliper
that is far behind the leading edge of an adjacent wheel?
This sounds like the bicycle is being tossed into a rock
crusher. Ejection forces from a rear mounted caliper are
real and undeniable, bending parts of the fork "from hitting
things" is unreal conjecture as is apparent from aluminum
parts of suspension forks that are not full of scrapes and
gouges on their front side "from hitting things".

> The mounts would also be under tension under braking,
> rather than compression which has an increased chance of
> failure. Specialized have already had a recall for
> mounting tab failures. Don't simply replace one problem
> with another and think through all the failure modes of a
> proposed solution before implementing it - Design Control
> 101.

There is nothing wrong with tension. If it were we couldn't
ride spoked wheels that have plenty of tension. In fact, no
matter how you make it, the bicycle (and n=most machines)
are full of tension and compression stresses. That is what
bending is.

Jobst Brandt [email protected]
 
"Gary Young" <[email protected]> wrote in message
news:[email protected]...
> "Mike Jacoubowsky/Chain Reaction Bicycles"
<[email protected]> wrote in message
news:<[email protected]>...
> > > If a single customer told you that their hub was
> > > slipping
in the
> > > dropouts under braking forces (or worse, the QR works
loose) then would
> > > you tell the manufacturers?
> >
> > I relayed reports of this issue, several months ago
> > (when it
first appeared
> > here), to a major manufacturer. Just because one of my
customers hasn't had
> > the issue doesn't mean it doesn't exist, and it would be
irresponsible not
> > to tell them about this thread. So, of course, you're
wondering what they
> > said, yada yada yada. In a nutshell, if there is an
> > issue,
it hasn't risen
> > about the noise level (meaning that it hasn't called
attention to itself).
> > If you're a manufacturer, you have to prioritize your
> > efforts
and deal with
> > what's in front of you. Theoretical stuff doesn't
> > attract
much attention
> > (and it attracts even less when it's not even a
> > product you
manufacture, but
> > rather one that's used industry-wide). Perhaps I
> > should have
explained it
> > this way before, and you might have better seen the
> > need to
produce data
> > from the sort of test I envisioned.
> >
>
> In other words, they were bullshitting you.
>
> As a general matter, you don't get out of legal
> obligations
simply
> because you prefer not to think about them. (Try it
> on the IRS
some
> time.)
>
> What's the name of this company? If they think
> making a safe
braking
> system is "theoretical stuff" too far over their
> heads, then
I'd like
> to avoid their products in the future.
>
> I'm not an expert on products liability, but I
> believe the law
deals
> more harshly with "design defects" than it does with
manufacturing
> defects. That is, the courts are more likely to assign
responsibility
> for accidents to a manufacturer if the problem was
> designed
into the
> product, as opposed to a flaw that was the unintended
> result of
the
> vagaries of the manufacturing process. I suspect this
> would be classified as a design defect.

This would be a design defect. Depending on the
jurisdiction, design defect cases are harder to prove than
manufacturing defects. In a design defect case, there is
usually some obligation to prove the existence of a
reasonable alternative design -- or that the risks of the
product outweigh its benefits. With a manufacturing defect,
you just have to show that the product is defective because
it was not manufacturered as designed. For example, a rat
got into the bladder mold and caused a giant inclusion in a
CF frame. It would be more complicated if the frame were
designed to include rats.

> Furthermore, I doubt the "we don't make it" excuse
> will wash.
If
> someone gives a manufacturer reason to believe that one of
> its suppliers is providing an unsafe product, but the
> manufacturer continues to rely on the supplier, then the
> manufacturer will
likely
> share in the liability. That's one of the reasons Ford and
Firestone
> are busy pointing fingers at each other.

Anyone one in the chain of manufacture and distribution is
subject to liability. If the down stream seller pays, it
tries to get its money back from the manufacturer -- Ford
sues Firestone. The manufacturer tries to prove that the
seller did something wrong. It swirls around for a few
years and then big bucks get paid. The big issue is recall
costs, which may or may not be recoverable. Insurance
coverage issues also complicate the picture since the
defective parts usually cause injury in a number of policy
periods. -- Jay Beattie.
 
Tony Raven wrote:

> Specialized have already had a
> recall for mounting tab failures.

When?

If you mean the recent recall of bikes with too large a
rotor installed, there were NO failures and no evidence that
there ever would be any failures. The problem was merely
that the combination had not been properly checked.

Puts the current situation regarding disks and QRs into
context, don't you think?

James
 
"Tony Raven" <[email protected]> wrote in message
news:[email protected]...
> Tim McNamara wrote:
> >
> > "Compelling is in the eye of the beholder" seems to
> > be what
you're
> > suggesting. Fair enough, I think. In the case of the
manufacturers,
> > I suspect that "compelling" is going to be equated with
"massive
> > product liability if we don't immediately fix it"
> > and they
don't see
> > that yet. I think they're burying their heads, but
> > that's
between
> > themselves, their lawyers and their liability insurance
carriers. In
> > the meantime, the users of these products are the ones
assuming the
> > risk.
>
> From the replys and lack of replies I had to the
> question I
asked earlier
> "Compelling" would seem to require at least having
> one person
from the many
> tens of thousand mountain bikers out there using discs
reporting to a
> manufacturer that they have experienced a problem of this
nature with their
> product. So far it looks as if no-one has done that
> in which
case it would
> not be unreasonable for them to assume that whatever the
theory, across a
> large population sample it is not happening in practice.
>
> Have a look at the number of bicycle related CPSC
> actions and
recalls
> (http://www.cpsc.gov/cgi-bin/recalldb/prod.asp, choose
> Bicycles
and
> Accessories and click Find)and ask why on earth would they
ignore this
> particular problem when handlebars, forks, stems, helmets,
whole bicycles,
> disc brake rotors etc are being recalled all the time,
sometimes at quite
> considerable financial cost to the manufacturer.
> Either it is
a massively
> complex and coordinated conspiracy involving multiple
> companies
across the
> globe and the US government or there is a simpler answer.
>

Right on. Maybe there is a problem, but I have not seen the
mass of injuries or lawsuits everybody is talking about.
Manufacturers of problem components commonly launch
voluntary recalls -- especially since much of the economic
burden is shared by the retailers who signed-up to do
warranty/recall work. I feel sorry for those guys. Recalls
are a good reason for a LBS not to be a dealer for anyone.
-- Jay Beattie.
 
Tony Raven wrote:

>
> From the replys and lack of replies I had to the question
> I asked earlier "Compelling" would seem to require at
> least having one person from the many tens of thousand
> mountain bikers out there using discs reporting to a
> manufacturer that they have experienced a problem of this
> nature with their product. So far it looks as if no-one
> has done that in which case it would not be unreasonable
> for them to assume that whatever the theory, across a
> large population sample it is not happening in practice.

But surely you have to agree that it _does_ happen in
practice (where "it" means at a minimum a failure of
indeterminate cause with the front wheel attachment, even if
you dispute the design fault). You only have to follow the
links on my web page to see that (and don't pretend you do
not read STW yourself). Further, it is also clear to anyone
who had not closed their eyes that the number of failures
whatevver the cause is much much higher with disk brakes (3
times in a group ride, and no fewer than 6 times for a
journalist testing a bike!)

It's true that mountainbikers have in the main not helped
themselves by their unwillingness to mention failures to the
manufacturers. There are a number of reasons which may
explain this. There is also clear evidence that the
manufacturers are ignoring any failures that they are
informed of (see the subject line).

I have also heard privately of other complaints that were
conveyed to the mnufacturers. There is more to this than you
are aware of, however much you try to put a reasonable spin
on their behaviour.

James
 
Gary Young wrote:

> I suspect that the industry is hoping there are no claims
> until the problem can be addressed quietly.

This is not so much a suspicion as an openly stated fact
within the industry.

James
 
carlfogel wrote:

> Dear Tom,
>
> Without inquiring into why your tricycle would be prone to
> pursuing sewage down those gratings, its address is
> actually:
>
> http://www.ihpva.org/incoming/2002/Dragonflyer/df1a.jpg
>
> http://www.ihpva.org/incoming/2002/Dragonflyer/index.html
>
> Ya gotta include the "Dragonflyer" part, or your blue
> beast stubbornly stays hidden down in the bowels of the
> internet.
>
> Carl "Never Fails to Proofread" gel

Dear Carl,

What happened here is that the IHPVA webmaster reorganized
the "incoming" directory, making my former correct URL's no
longer valid.

--
Tom Sherman - Quad Cities (Illinois Side)
 
[email protected] wrote:

> http://www.ihpva.org/incoming/2002/sunset/Sunset001.jpg
>
> That is certainly a compendium of mechanical oddities,
> unistrut fork, front spoke guard, primary and secondary
> chains with cross-over and dual tensioners. The tiller
> style steering is also unusual for using arm force while
> pedaling. How do you keep pant legs out of the chain?

Isn't "unistrut fork" an oxymoron?

The spoke guard is for running the front chain off the idler
for slightly reduced drivetrain friction.

The two chain system has several advantages to compensate
for the additional mechanical complexity. The step-up
provides a virtual 30" (76
cm) diameter drivewheel for gearing purposes, so wide range
gearing is available with conventional sized chainrings
and a regular front derailleur. There are no cross-
gears, and having a single sprocket for each chain at
the step-up makes for an excellent chainline.

Pulling on the handlebars of a recumbent does little except
make the handling wobbly.

> In the line with this thread, I cannot see riding this on
> steep trails or trails at all for that matter.

As for riding on off-road downhill trails, the concept here
is thread drift. As for riding the Sunset at all, even
though I have poor gross (and fine for that matter) motor
coordination and am below average in learning physical
skills, I ride it with no problem and have much more fun
doing so than I ever did on an upright bicycle.

--
Tom Sherman - Quad Cities (Illinois Side)
 
carlfogel wrote:

> Dear Jobst,
>
> Here's a double-size picture of the rocket recumbent with
> dreadfully artistic lines and angles calculated off x-y
> pixel positions.
>
> If anything, it looks as if it would brake even better
> than I originally thought--about a 50 degree angle from
> COG to contact patch versus 61 degrees for the upright
> with an almost identical wheelbase in "Bicycling Science."
>
> http://home.comcast.net/~carlfogel/download/rocketdia-
> gram.jpg
>
> or
>
> http://tinyurl.com/yrtgo
>
> Possibly the recumbent that you remember wasn't quite
> identical to this one?

Dear Carl,

The seat height will be about an inch lower than the top of
the seat cushion for an average rider (and lower for one
who consumes an excessive amount of sucrose sweetened
torroidal foods).
>
> As for Tom's elusive blue Dragonflyer, there are a dozen
> lurid views here:
>
> http://www.ihpva.org/incoming/2002/Dragonflyer
>
> Yes, double-checked that one. (Sorry about my incorrect
> corrections of addresses.) This picture gives an almost
> side-view:
>
> http://www.ihpva.org/incoming/2002/Dragonflyer/df2.jpg
>
> Weird-lookin' thing!

But you must appreciate the OEM custom Phil Wood hubs (each
worth at least 4 Roadmaster Mt. Fury's).

--
Tom Sherman - Quad Cities (Illinois Side)
 
Originally posted by Tom Sherman
carlfogel wrote:

> Dear Jobst,
>
> Here's a double-size picture of the rocket recumbent with
> dreadfully artistic lines and angles calculated off x-y
> pixel positions.
>
> If anything, it looks as if it would brake even better
> than I originally thought--about a 50 degree angle from
> COG to contact patch versus 61 degrees for the upright
> with an almost identical wheelbase in "Bicycling Science."
>
> http://home.comcast.net/~carlfogel/download/rocketdia-
> gram.jpg
>
> or
>
> http://tinyurl.com/yrtgo
>
> Possibly the recumbent that you remember wasn't quite
> identical to this one?

Dear Carl,

The seat height will be about an inch lower than the top of
the seat cushion for an average rider (and lower for one
who consumes an excessive amount of sucrose sweetened
torroidal foods).
>
> As for Tom's elusive blue Dragonflyer, there are a dozen
> lurid views here:
>
> http://www.ihpva.org/incoming/2002/Dragonflyer
>
> Yes, double-checked that one. (Sorry about my incorrect
> corrections of addresses.) This picture gives an almost
> side-view:
>
> http://www.ihpva.org/incoming/2002/Dragonflyer/df2.jpg
>
> Weird-lookin' thing!

But you must appreciate the OEM custom Phil Wood hubs (each
worth at least 4 Roadmaster Mt. Fury's).

--
Tom Sherman - Quad Cities (Illinois Side)

Dear Tom,

The Fury Roadmaster, however, is still in production.

Carl Fogel
 
James Annan wrote:
> Tony Raven wrote:
>
>
>> Specialized have already had a
>> recall for mounting tab failures.
>
> When?
>
> If you mean the recent recall of bikes with too large a
> rotor installed, there were NO failures and no evidence
> that there ever would be any failures. The problem was
> merely that the combination had not been properly checked.
>
> Puts the current situation regarding disks and QRs into
> context, don't you think?
>
> James

I should choose my words more carefully. I should have said
that "Specialized have already had a recall for _potential_
mounting tab failures"

The CPSC release said:

Hazard: During heavy braking, the brake tabs on the front
forks could break off, possibly causing a loss of control
and fall from the bicycle.

Tony
 
in message <[email protected]>, Chris Malcolm
('[email protected]') wrote:

> Simon Brooke <[email protected]> writes:
>
>>in message <[email protected]>, Tim
>>McNamara ('[email protected]') wrote:
>
>>> Ummm, no. The limit of braking power is not the force
>>> with which the brake can clamp onto the rim, but the
>>> coefficient of friction between the tire and the riding
>>> surface. Clean dry pavement offers a higher coefficient
>>> of friction than dirt with the same tires, although
>>> perhaps pumice or slickrock might equal or exceed cement
>>> pavement.
>
>>Speaking as someone who regularly rides both types of
>>bikes, I don't agree with you. Mind you, I could be wrong
>>- the caliper brakes on my road bike are single pivot and
>>not especially clever. I don't know the extreme limits of
>>braking on either system, since I'm now to old and have
>>too much respect for the fragility of my skull to just
>>slam on the anchors and see what happens. But I do know
>>that I can stop shorter - a lot shorter - on my hill bike
>>than on my road bike, on the same road and braking from
>>the same speed.
>
> I presume that on both bikes you can brake hard enough to
> skid the front wheel.

No idea. I don't do so; perhaps I could, but like I say I
have no interest in the 'ejector seat' technique of
coming to rest.

> If you're higher off the ground on your road bike it won't
> be able to stop as fast.

Don't think so. The saddles on all my bikes are the same
height, modulo normal suspension compression; likewise the
handlebars. However the angles on the hill bikes are a lot
slacker, and I do habitually slip off hte back of the saddle
to brake hard on the hill bikes. So perhaps the difference
is just that I get my CoG further back.

--
[email protected] (Simon Brooke)
http://www.jasmine.org.uk/~simon/ There's nae Gods, an
there's precious few heroes but there's plenty on the dole
in th Land o th Leal; And it's time now, tae sweep the
future clear o th lies o a past that we know wis never real.
 
Originally posted by Simon Brooke
in message <[email protected]>, Chris Malcolm
('[email protected]') wrote:

> Simon Brooke <[email protected]> writes:
>
>>in message <[email protected]>, Tim
>>McNamara ('[email protected]') wrote:
>
>>> Ummm, no. The limit of braking power is not the force
>>> with which the brake can clamp onto the rim, but the
>>> coefficient of friction between the tire and the riding
>>> surface. Clean dry pavement offers a higher coefficient
>>> of friction than dirt with the same tires, although
>>> perhaps pumice or slickrock might equal or exceed cement
>>> pavement.
>
>>Speaking as someone who regularly rides both types of
>>bikes, I don't agree with you. Mind you, I could be wrong
>>- the caliper brakes on my road bike are single pivot and
>>not especially clever. I don't know the extreme limits of
>>braking on either system, since I'm now to old and have
>>too much respect for the fragility of my skull to just
>>slam on the anchors and see what happens. But I do know
>>that I can stop shorter - a lot shorter - on my hill bike
>>than on my road bike, on the same road and braking from
>>the same speed.
>
> I presume that on both bikes you can brake hard enough to
> skid the front wheel.

No idea. I don't do so; perhaps I could, but like I say I
have no interest in the 'ejector seat' technique of
coming to rest.

> If you're higher off the ground on your road bike it won't
> be able to stop as fast.

Don't think so. The saddles on all my bikes are the same
height, modulo normal suspension compression; likewise the
handlebars. However the angles on the hill bikes are a lot
slacker, and I do habitually slip off hte back of the saddle
to brake hard on the hill bikes. So perhaps the difference
is just that I get my CoG further back.

--
[email protected] (Simon Brooke)
http://www.jasmine.org.uk/~simon/ There's nae Gods, an
there's precious few heroes but there's plenty on the dole
in th Land o th Leal; And it's time now, tae sweep the
future clear o th lies o a past that we know wis never real.

Dear Tim and Simon,

A couple of side-view pictures of bicycles
and either riders or suggestions about
COG would be worth thousands of words.

A typical paint program will let you draw
admirably straight lines, and programs
like MB-Ruler 0.93 on this freeware page
provide a transparent onscreen protractor
and ruler:

http://www.ramlende.com/graphics.html

Haven't had so much fun since they took
the scissors away from me in grade school.

I'd be happy to host any pictures for comparison
and even do the work of drawing and measuring
angles.

The chief area of debate would likely be the
center of mass.

Don't eat the paste.

Carl Fogel
 
Hello everybody,

> A typical paint program will let you draw admirably
> straight lines, and programs like MB-Ruler 0.93 on this
> freeware page provide a transparent onscreen protractor
> and ruler:
>
> http://www.ramlende.com/graphics.html
>
> Haven't had so much fun since they took the scissors away
> from me in grade school.
>
> I'd be happy to host any pictures for comparison and even
> do the work of drawing and measuring angles.
>
> The chief area of debate would likely be the center
> of mass.

On the MB-Ruler hompage

http://www.Markus-Bader.de/MB-Ruler/index.htm

the update to MB-Ruler 1.3 (with screen loupe, RGB picker
and multi monitor support) is already available.

Bye

Markus
 

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