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

wrote in message
...
Richard Brockie writes:

I didn't see a picture of this tricycle but short wheelbase recumbent
bicycles, ones where pedal cranks are ahead of the front wheel, do
endo's more easily than a conventional bicycle. Drawing a visual line
from the rider's belly button (rider CG) to the contact patch of the
front wheel shows that the CG is no better positioned than that of a
conventional bicycle and usually worse.

Not necessarily. I measured both my recumbent and my wedgie and the
recumbent had the angle from the contact patch to the rider CoG set about 15
degrees further back than the tourer. My recumbent is a fairly low one,
with the seat inclined at around 30 degrees, and my tourer is a 24 1/2"
frame; higher-seated SWB recumbents will be different of course as will
smaller-framed wedgies or those with different geometry. And indeed it will
change from rider to rider.

Thus far I have not managed to raise the rear wheel of the 'bent. I have
tried. I have raised the rear wheel of the tourer. The recumbent has
hydraulic discs, the tourer has conventional cantilever rim brakes.

--
Guy
===
May contain traces of irony. Contents liable to settle after posting.
http://www.chapmancentral.co.uk

88% of helmet statistics are made up, 65% of them at Washington University

wrote:
In any
case, I have never seen a recumbent on any of the trails in the Santa
Cruz Mountains nor in the Alps in the many years that I have ridden.

Not, admittedly, the world's best photograph by the time it got here, but
http://legslarry.8bit.co.uk/BikeStull/Alleweders.jpg shows Ymte Sybrandy
(left) and Theo van Andel at the summit of the St Gotthard pass, during the
course of a seventeen day round trip from Lelystad to Magliano Alpi and
back. Full story and further pictures at
http://www.legslarry.beerdrinkers.co.uk/PDF/Issue48.pdf

--

Dave Larrington - http://www.legslarry.beerdrinkers.co.uk/
================================================== =========
Editor - British Human Power Club Newsletter
http://www.bhpc.org.uk/
================================================== =========

In article , Tim McNamara wrote:
bomba writes:

On Fri, 26 Mar 2004 12:06:36 -0800, Carl Fogel wrote:

Do disk brakes on bicycles actually offer more braking force than
rim caliper brakes? If so, is the greater force useful? That is,
would a street bike be able to stop shorter with a disk brake than
with a caliper brake?

Yes, yes and yes.

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.

Ummm, no. If you can brake hard enough to lift the rear wheel, that's
the limiting factor, and any further improvement in grip between the
front tyre and ground doesn't make a significant difference.
Disks, of course, don't change that.

"Alan Braggins" wrote in message
...

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.

Ummm, no. If you can brake hard enough to lift the rear wheel, that's
the limiting factor, and any further improvement in grip between the
front tyre and ground doesn't make a significant difference.
Disks, of course, don't change that.

James rides tandem and I ride a recumbent, so for both of us the former is
more signifcant than the latter.

--
Guy
===
May contain traces of irony. Contents liable to settle after posting.
http://www.chapmancentral.co.uk

88% of helmet statistics are made up, 65% of them at Washington University

wrote:



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!

James

"Chris Malcolm" wrote in message
...
bomba writes:

Since most bike brakes are capable of skidding the front wheel in most
circs, all that better brakes give you is finer control of braking
force and less grip effort.

And less fade. And less rim wear. And less chance of water reducing
braking force, since the braking surface is away from the contact point.
And better braking if your bike is not a standard wedgie (e.g. tandem /
recumbent). And less chance of causing a tyre blowout due to rim heating
(allegedly).

--
Guy
===
May contain traces of irony. Contents liable to settle after posting.
http://www.chapmancentral.co.uk

88% of helmet statistics are made up, 65% of them at Washington University

Russ wrote:


It's very easy for the manufacturers to fix on new forks - just put the
mounting tabs on the front of the fork - nothing else is needed. BUT, and
it's a big but, in doing this the manufactuers would effectively be
admitting that there's a *potential* problem and would open the floodgates
to claims and demand for retrospective fixing of the problem. Whilst there
are no large legal cases (and hence costs) relating to this particular
problem then there's no reason for manufacturers to risk changing it. It's
difficult to see how any safety body can address the problem while the
vibrating loose theory remains just that, a theory (albeit one that's been
accepted in court cases in the US albeit unrelated to disc brakes) - the QR
and the lawyers lips should in the vast majority of cases ensure safety,
it's just that one in a million one where thay don't, this will need to be
forced on he manufacturers by cost implications or possibly by consumer
pressure.


There is a very real reason for manufacturers not to ignore it and that is if
there is now an accident that can be shown in court to be a result of wheel
ejection, the manufacturers would face punitive damages. The intention is to
make sure that ignoring it in the way you suggest is not a viable option for a
company or its management unless they believe they are on very solid ground.

Tony

tcmedara wrote:

My problem here is that
you (and many others) fail to acknowledge that there's lots of unanswered
questions remaining.

The most interesting question (IMO the only meaningful one remaining,
but I would say that) is how often does it happen? Plenty of people say
they have never heard of it, but it seems very likely to me that it is
under-reported, and overlooked when it is mentioned. I offer no proof
(as always:-), merely two anecdotes.

1. Critics from a.m-b deny that the problem happens amongst the "real
mountain bikers" there. In fact, last time this topic generated some
noise, someone started a thread there to ask if anyone had experienced
it. In amongst all the noise, someone said that yes, they had indeed
experienced it, on their disk-braked bike, never with rim brakes.

2. Just a few days ago another poster in a.m-b mentioned their wheel
falling out. The rear wheel this time, but a little googling suggests it
was on a disk-braked bike which quite probably came with skewers that
seem to have developed quite a reputation for unscrewing. I could be
wrong on several counts with this story, but no-one else even seeemed to
consider the possibility that it was related to disk brake forcing. It
was just one more reason to check your bike carefully...**** happens,
man. It seems odd that a skewer coming loose can be "just one of those
things" and yet there is such vehement rejection of a simple explanation
as to how it can happen, but that's a separate issue...

When this story comes up again (and rest assured, it most certainly
will), the same crowd will insist that they have never heard of any
cases of it happening in the real world. They are simply not prepared to
"see" the cases where it has (or at least may have) happened.

Contrast with singletrackworld, where although there are still many
critics, there are plenty who are starting to agree that it really can
happen. So it tends to get noticed more, and when as many as 3 people
find their skewers loose in a single group ride, it is even considered
worth commenting on.

James

Tony Raven wrote:


There is a very real reason for manufacturers not to ignore it and that is if
there is now an accident that can be shown in court to be a result of wheel
ejection, the manufacturers would face punitive damages.

And indeed prison sentences, AIUI. But in practice I suspect they may
get away with claiming that they genuinely had no reason to believe that
the problem occurs in the real world. So long as the reports do not come
in, this excuse might hold up.

The intention is to
make sure that ignoring it in the way you suggest is not a viable option for a
company or its management unless they believe they are on very solid ground.

Perhaps, but the number of companies who _do_ end up with punitive fines
and prison sentences suggests that they frequently miscalculate. We've
already seen Mark Hickey's suggestion as to how the law should be handled...

The "solid ground" argument sits awkwardly with the extreme reluctance
of several people to behave openly and ethically. If there is truly
nothing to fear, why are they doing this? It's the deceit and lies that
has motivated me as much as (perhaps more than) the actual problem itself.

James

Mark Hickey wrote in message . ..
(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?

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


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?