Who wants broken helmets?

Eatmorepies said:

A friend of mine fell off recently and banged his head - no damage to him but the polystyrene
shell of his helmet broke. I have a vague memory that some research organisation wanted damaged
helmets.

If it's less than 3 years old and a decent make then the manufacturer would probably be interested,
and may well offer a discount on a replacement. Giro certainly do this, and I believe a few other
manufacturers do as well.

--
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Thomas Paine

Eatmorepies wrote in message ...

Quoted message said:

A friend of mine fell off recently and banged his head. No damage to him but the polystyrene shell
of his helmet broke.

Well at least this shows the doubters that helmets ARE of benefit, as the cracking of the shell
was created as a result of the energy dissipation of the impact. Rather crack a helmet than
cracking his head!

On Sun, 05 Oct 2003 20:15:14 +0100, Eatmorepies did issue forth:

Quoted message said:

A friend of mine fell off recently and banged his head - no damage to him but the polystyrene
shell of his helmet broke. I have a vague memory that some research organisation wanted damaged
helmets.

Don't know about donating it to anyone, but when I cracked a helmet, it lived on as a rather
fetching fruit bowl.

Huw

Steve said:

Quoted message said:

A friend of mine fell off recently and banged his head. No damage to him but the polystyrene
shell of his helmet broke.

Well at least this shows the doubters that helmets ARE of benefit, as the cracking of the shell
was created as a result of the energy dissipation of the impact.

Errr. No, if the energy had dissipated then there woudn't have a cranked helmet but a flattened one.

Quoted message said:

Rather crack a helmet than cracking his head!

You are making the common mistake of looking at the outcome to the helmet and transferring that
to the head.

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and dealers.

Steve said:

Eatmorepies wrote in message ...

Quoted message said:

A friend of mine fell off recently and banged his head. No damage to him but the polystyrene shell
of his helmet broke.

Well at least this shows the doubters that helmets ARE of benefit, as the cracking of the shell
was created as a result of the energy dissipation of the impact. Rather crack a helmet than
cracking his head!

Only if the friend can go and fall off in exactly the same way without the helmet and show there was
an injury.

If I cycle with an egg on my head and fall off and the egg breaks does that shoe that eggs ARE
of benefit?

You have to look at large population studies to show benefit. I've yet to see one that does.

--
Chris dot Gerhard at btclick dot com.

Chris Gerhard said:

Steve said:

Eatmorepies wrote in message ...

Quoted message said:

A friend of mine fell off recently and banged his head. No damage to him but the polystyrene
shell of his helmet broke.

Well at least this shows the doubters that helmets ARE of benefit, as the cracking of the shell
was created as a result of the energy dissipation of the impact. Rather crack a helmet than
cracking his head!

Only if the friend can go and fall off in exactly the same way without the helmet and show there
was an injury.

If I cycle with an egg on my head and fall off and the egg breaks does that shoe that eggs ARE of
benefit?

What a stupid and facile argument. It is just that sort of argument that damages the sound case
against compuslion.

pk

marc said:

Steve said:

Quoted message said:

A friend of mine fell off recently and banged his head. No damage to him but the polystyrene
shell of his helmet broke.

Well at least this shows the doubters that helmets ARE of benefit, as the cracking of the shell
was created as a result of the energy dissipation of the impact.

Errr. No, if the energy had dissipated then there woudn't have a cranked helmet but a
flattened one.

while there might be reasonable arguments that a bumped helmet would not equate to a bumped head, I
suspect that a broken helmet really has protected the user.

I've done both. Fallen off and bumped my helmet on the ground when in all probability my head would
have missed had I not been wearing a helmet, and I've come off and ended up with a helmet with a
shattered polystyrene shell (and me in hospital) I'm glad I didn't choose to discard my helmet after
the first fall.

pk

Steve said:

Well at least this shows the doubters that helmets ARE of benefit, as the cracking of the shell
was created as a result of the energy dissipation of the impact. Rather crack a helmet than
cracking his head!

I dropped my helmet recently, all of 4 feet onto a flat surface, and it cracked. That was a trivial
impact with a barely noticeable force. OTOH a _crushed_ helmet _might_ absorb a significant amount
of energy.

James

Steve said:

Eatmorepies wrote in message ...

Quoted message said:

A friend of mine fell off recently and banged his head. No damage to him but the polystyrene
shell of his helmet broke.

Well at least this shows the doubters that helmets ARE of benefit, as the cracking of the shell
was created as a result of the energy dissipation of the impact. Rather crack a helmet than
cracking his head!

Doesn't show any such thing to me.

How much energy did it dissipate? How do you know it was enough to make the difference between
significant uinjury or not?

Perhaps, if he hadn't been wearing teh helmet, he wouldn't have fallen off.

How do you know that his head wouldn't have missed teh ground entirely if he hadn't had a helmet on?

regards, Ian SMith
--
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PK said:

Quoted message said:

Quoted message said:

Well at least this shows the doubters that helmets ARE of benefit, as the cracking of the shell
was created as a result of the energy dissipation of the impact.

Errr. No, if the energy had dissipated then there woudn't have a cranked helmet but a
flattened one.

while there might be reasonable arguments that a bumped helmet would not equate to a bumped head,
I suspect that a broken helmet really has protected the user.

That wasn't my argument. I was simply pointing out the fallacy that a the helmet was dissipating any
energy by cracking.

"Huw Pritchard" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

On Sun, 05 Oct 2003 20:15:14 +0100, Eatmorepies did issue forth:

Quoted message said:

A friend of mine fell off recently and banged his head - no damage to

him

Quoted message said:

Quoted message said:

but the polystyrene shell of his helmet broke. I have a vague memory

that

Quoted message said:

Quoted message said:

some research organisation wanted damaged helmets.

Don't know about donating it to anyone, but when I cracked a helmet, it lived on as a rather
fetching fruit bowl.

Huw

eerrrrmm...had you done much sweating into it, Huw ? ;-)

Dave.

Quoted post said:

Originally posted by Marc
PK <[email hidden]> wrote:

That wasn't my argument. I was simply pointing out the fallacy that a the helmet was dissipating any
energy by cracking.

Considering helmets do not crack on their own, some amount of energy must have been required to crack the helmet. What is not known here is how much energy was required.

SCEhardt <[email hidden]> wrote in message
news:<[email hidden]>...

Quoted message said:

Considering helmets do not crack on their own, some amount of energy must have been required to
crack the helmet. What is not known here is how much energy was required.

Ah! The inevitable entry of a cyclingforums sock puppet into any helmet thread.

--
Dave...

SCEhardt said:

Considering helmets do not crack on their own, some amount of energy must have been required to
crack the helmet. What is not known here is how much energy was required.

It doesn't take a genius to work it out. I recently broke my helmet by dropping it about 3 feet onto
the ground. Assuming it weighs as much as 500g, I make that 5 joules of energy.

James

(...but that 5J could be the difference between life and death...)

Quoted post said:

Originally posted by Ian Smith

BOn Mon said:

Eatmorepies wrote in message ...

Quoted message said:

A friend of mine fell off recently and banged his head. No damage to him but the polystyrene
shell of his helmet broke.

Well at least this shows the doubters that helmets ARE of benefit, as the cracking of the shell
was created as a result of the energy dissipation of the impact. Rather crack a helmet than
cracking his head!

Doesn't show any such thing to me.

How much energy did it dissipate? How do you know it was enough to make the difference between
significant uinjury or not?

Perhaps, if he hadn't been wearing teh helmet, he wouldn't have fallen off.

How do you know that his head wouldn't have missed teh ground entirely if he hadn't had a helmet on?

regards, Ian SMith
--
|\ /| no .sig
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HAHAHAHA

Missed the ground... um ok I guess the evidence here doesn't CONCLUSIVELY PROVE that in this particular case the helmet prevented an injury.... But to suggest that one of the following happened:

1. The fall was such that the force of impact was just enough to damage the helmet, but not quite enough to cause any damage to an unprotected head...

2. The cosmic repercussions of putting on a helmet increased the chance of an accident....

3. The fall was such that his (hypothetically unprotected) head would have come to within 2cm of the ground without impact...

is downright stubborn lol!

I'll give you that a cracked helmet isn't _proof_ of protection, but it's pretty damn strong evidence.

btw for the rest of you, the question is not so much the amount of energy dissipated, but the time taken for the head to be brought to a stop (or rebound) from 15mph. During impact, the helmet acts to spread the momentum change out over a longer time period, thereby decreasing the magnitude of the force exerted on the head.

pineapple said:

Ian Smith said:

Steve said:

Well at least this shows the doubters that helmets ARE of benefit, as the cracking of the
shell was created as a result of the energy dissipation of the impact. Rather crack a
helmet than cracking his head!

Doesn't show any such thing to me. How much energy did it dissipate? How do you know it was
enough to make the difference between significant uinjury or not? Perhaps, if he hadn't been
wearing teh helmet, he wouldn't have fallen off. How do you know that his head wouldn't have
missed teh ground entirely if he hadn't had a helmet on?

HAHAHAHA
3. The fall was such that his (hypothetically unprotected) head would have come to within 2cm of
the ground without impact...

is downright stubborn lol!

No it's not, it's quite realistic. Most people have years of reflexes trained to keep their head
from hitting things. Increasing the size of your head only slightly quite likley significantly
increases the number of collsions.

Quoted message said:

btw for the rest of you, the question is not so much the amount of energy dissipated, but the
time taken for the head to be brought to a stop (or rebound) from 15mph. During impact, the
helmet acts to spread the momentum change out over a longer time period, thereby decreasing the
magnitude of the force exerted on the head.

Not if it cracks rather than crushes it won't. The two things are (effectively) synonymous. You can
talk about energy or you can talk about acceleration profiles, but in either case a helmet cracking
where it should crush is demonstration that it didn't work as it should, and if it didn't work as it
should, drawing conclusions about it's efficacy is clearly tenuous.

regards, Ian SMith
--
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pineapple said:

I'll give you that a cracked helmet isn't proof of protection, but it's pretty damn strong
evidence.

Evidence that the helmet dissipated some energy, yes. So it may have turned a nasty headache or even
concussion into a mild headache. A worthy aim, as long as the crash wasn't caused by carelessness
brought on by the Cloak of Invincibility effect.

Doesn't change the fact that there is no statistical correlation between helmet wearing rates and
head injury rates, though, unfortunately.

--
Guy chapmancentral.demon.co.ukchapmancentral.demon.co.ukOpen ↗ "Sic hoc adfixum in obice legere potes, et liberaliter
educatus et nimis propinquus ades"

Just zis Guy said:

A worthy aim, as long as the crash wasn't caused by carelessness brought on by the Cloak of
Invincibility effect.

Just out of interest. Do lights contribute to this effect?

Simonb

Simonb said:

Just zis Guy said:

A worthy aim, as long as the crash wasn't caused by carelessness brought on by the Cloak of
Invincibility effect.

Just out of interest. Do lights contribute to this effect?

Simonb

I reckon they do. I get a feeling of terrible exposure if one of my two rear lights is out. And I am
much more cautious.

The other day I left my front lamp on all day and only had a blueish LED backup. I crept home and
even considered using the shared use path.

The important difference is that a blaze of lights *really* does reduce accidents whereas a
helmet does not.

ie more lights may mean more accidents due to the cyclist being a little more gung-ho but this
increase is far outweighted by the reduction of accidents caused by car users failing to see
said cyclist.