Cyclist wins broken handlebar case

Tony Raven said:

http://www.bailii.org/ew/cases/EWHC/QB/2007/1667.html

Alan Ide fell off his Marin FS mountain bike on the South Downs Way and
suffered serious head injuries despite a h**m*t (Shirley some mistake?:
Ed) The judge found that his handlebar had failed due to a defect and
that liability lay with Marin's importer ATB Sales. The scale of the
damages is still awaited.

Tony

I have the same bike of the same age, glad I replaced the bar now. (for
reasons of fit rather than the quality of it)

Steve

Quoted message said:

http://www.bailii.org/ew/cases/EWHC/QB/2007/1667.html

Alan Ide fell off his Marin FS mountain bike on the South Downs Way and
suffered serious head injuries despite a h**m*t (Shirley some mistake?:
Ed) The judge found that his handlebar had failed due to a defect and
that liability lay with Marin's importer ATB Sales. The scale of the
damages is still awaited.

"Dr Morgan also challenged Dr Chinn's conclusions [...] that the right side
of the handlebar revealed significant levels of bending. (Dr Chinn
subsequently admitted that he had not realised that the handlebars were
designed with a bend in them)."

Ooops!

Mark wrote on 21/07/2007 19:29:

Quoted message said:

Quoted message said:

http://www.bailii.org/ew/cases/EWHC/QB/2007/1667.html

"Dr Morgan also challenged Dr Chinn's conclusions [...] that the right side
of the handlebar revealed significant levels of bending. (Dr Chinn
subsequently admitted that he had not realised that the handlebars were
designed with a bend in them)."

Ooops!

Also, a tangential snigger from me for...

"Mr Higgins set the [DataTaker] logger at 90 Hz per second, which
enabled 90 readings to be taken per second of the force applied to the
handlebars."

Sorry... that's the physicist in me.

Peter

--
http://www.scandrett.net/lx/
http://www.scandrett.net/bike/

Peter Scandrett said:

Also, a tangential snigger from me for...

"Mr Higgins set the [DataTaker] logger at 90 Hz per second, which
enabled 90 readings to be taken per second of the force applied to the
handlebars."

Sorry... that's the physicist in me.

I once had the challenge of working out how to answer a question from a
US judge, in a case in which I was an expert witness, when he asked "So
how many milligrams thick does it need to be?"

Tony

Peter Scandrett said:

Mark wrote on 21/07/2007 19:29:

Quoted message said:

Quoted message said:

http://www.bailii.org/ew/cases/EWHC/QB/2007/1667.html

I've read through that, agree that the bar snapped causing the
accident but don't agree that it was definitely down to a
manufacturing defect rather than wear & tear.

Jon

Quoted message said:

don't agree that it was definitely down to a
manufacturing defect rather than wear & tear.

Nor does the judge! Given the differing evidence by the expert witnesses I
suspect there'll be an appeal.

Mark said:

Nor does the judge! Given the differing evidence by the expert witnesses I
suspect there'll be an appeal.

That's not grounds for an appeal. Appeals do not question the judge's
conclusions from the evidence, only whether the correct procedures were
followed and the law correctly applied. The evidence is only
re-evaluated on appeal if new evidence has come to light that could not
have reasonably been known at the time of the original case.

Tony

Paul Boyd said:

It does seem possible that the bars could have snapped as a
result of the crash because of this crack, rather than the other way
around. The victim had no memory of the accident and there were no
witnesses, so I can't see how anything can be absolutely proven either
way - in fact it looks more like the onus is on the rider rather than
the manufacturer - it's fairly easy to score a bar when fitting and
start off a fatigue crack.

Except the breakage was created by a force in the direction of hands
resting on handlebars from above and behind. If it was from the crash
you would expect the force to be in the opposite direction - either
backwards or upwards given the way it fell.

Tony

This case seems to prove what a silly idea it is to CNC tiny stress-
raising grooves in a handlebar. Even smooth aluminium alloy handlebars
have been known to suffer fatigue failures, but at least in a smooth
bar the user has some small chance of spotting the crack before it has
catastrophicaly weakened the handlebar.

On Mon, 23 Jul 2007 10:28:44 +0100

Tony Raven said:

Except the breakage was created

I think the point was evidence of damage that was old at the time
of the crash.

--
not me guv

Tony Raven said the following on 23/07/2007 10:28:

Quoted message said:

Except the breakage was created by a force in the direction of hands
resting on handlebars from above and behind. If it was from the crash
you would expect the force to be in the opposite direction - either
backwards or upwards given the way it fell.

Ah - I didn't notice that bit. I still say that the rider /could/ (not
necessarily "should"😉 have noticed that crack forming as it appeared to
have been forming for some time. I wonder if he'd been idly wondering
what that creaking sound [1] was beforehand - I've been there and then
been shocked when I discovered what it was and how far it had gone (in
my case a crank arm to the "stop riding now" extent). Like I said
though, how many of us do check these things as often as we should, if
at all. Is the very act of removing then refitting a bar going to
increase the risk of a fatigue failure? I'm not a metallurgist!

[1] hypothetically - it sounds like the rider wouldn't have remembered
if there was a creaking or not.

--
Paul Boyd
http://www.paul-boyd.co.uk/

Paul Boyd usenet.dont.work@plusnet said:

Tony Raven said the following on 23/07/2007 10:28:

[snip] ... I still say that the rider /could/ (not
necessarily "should"😉 have noticed that crack forming as it appeared to
have been forming for some time. I wonder if he'd been idly wondering
what that creaking sound [1] was beforehand - I've been there and then
been shocked when I discovered what it was and how far it had gone (in
my case a crank arm to the "stop riding now" extent). Like I said
though, how many of us do check these things as often as we should, if
at all. Is the very act of removing then refitting a bar going to
increase the risk of a fatigue failure? I'm not a metallurgist!

The machined grooves will have masked the crack. The mode of failure
of the right side of the handlebar when tested after the accident (it
tore off rather than bending and with less force than that which bent
the comparison products) indicate that this side also had fatigue
cracks, that were too fine and/or masked by the machining to be seen
by any of the metallurgists present. If you read the report you'll see
that one of them acknowledges this could be the case. So it's
unreasonable to expect the user to see such a crack against such a
surface finish. A good decision by the judge IMHO.

The surface of handlebars can indeed be damaged by a stem. A common
cause of similar failures to this one involves a fatigue crack
initiating at a groove formed in the handlebar when it slips in the
stem, due to inadequate tightening or poor fit. If the bar is a tight
fit it may be necessary to twist it to and fro in order to get it out
the stem, and in that case such marring of the surface is almost
inevitable. In that case the handlebar really ought to be discarded.
Another reason, if one be needed, to favour front-opening stems!

In article <[email hidden]>, CJ
[email hidden] says...

Quoted message said:

If the bar is a tight
fit it may be necessary to twist it to and fro in order to get it out
the stem, and in that case such marring of the surface is almost
inevitable. In that case the handlebar really ought to be discarded.

It's usually not difficult to spring the stem a bit wider with some sort
of wedge or lever.

Rob Morley said:

It's usually not difficult to spring the stem a bit wider with some sort
of wedge or lever.

Put the stem bolt in from the other direction (the threaded side) and
put a penny or bit of metal into the gap. Simply screw the bolt in and
lever the stem open.

Tony

"Tony Raven" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Peter Scandrett said:

Also, a tangential snigger from me for...

"Mr Higgins set the [DataTaker] logger at 90 Hz per second, which enabled
90 readings to be taken per second of the force applied to the
handlebars."

Sorry... that's the physicist in me.

I once had the challenge of working out how to answer a question from a US
judge, in a case in which I was an expert witness, when he asked "So how
many milligrams thick does it need to be?"

four ounces

Quoted message said:

Tony