Fabian Cancellara sparks helmet debate on Twitter, says all cyclists should wear one

batch2103 wrote:

The debate on helmet wearing should never go away. It has to be kept very much in the publics consciousness ... otherwise we might not have any conscious to ponder?

Don't be ridiculous. The 'helmet debate' most definitely *should* go away as there is no evidence whatsoever that helmets do anything to reduce injury rates.

We've been running 'studies' of compulsory helmet-wearing in Australia, New Zealand and some parts of Canada for nearly 20 years now. If helmets really did help, then it should have shown up in the statistics by now.

HarryCallahan wrote:

"velocity of any impact would in all likelihood be well above the maximum stipulated under EU standards"

Doesn't mean the helmet isn't effective. Better to have concussion than mashed brains.

Except the impact mitigation for cycle helmet material is not to lessen the impact, but in fact to take it all unto itself

This results in the rule that ANY impact involving your helmet has almost certainly resulted in it splitting

In a real crash, impact directly to the helmet will result in it splitting like a watermelon hit by a hammer - providing NO protection to the rider

mad_scot_rider wrote:

HarryCallahan wrote:

"velocity of any impact would in all likelihood be well above the maximum stipulated under EU standards"

Doesn't mean the helmet isn't effective. Better to have concussion than mashed brains.

Except the impact mitigation for cycle helmet material is not to lessen the impact, but in fact to take it all unto itself

No, that's not a fact - one of the primary functions is to increase the time over which deceleration of the head occurs. That is mitigation not prevention or total protection.

mad_scot_rider wrote:

This results in the rule that ANY impact involving your helmet has almost certainly resulted in it splitting

There is no such rule.

mad_scot_rider wrote:

In a real crash, impact directly to the helmet will result in it splitting like a watermelon hit by a hammer -

Come on, that's clearly dependant on the impact unless you're appealing to your 'rule'.

mad_scot_rider wrote:

providing NO protection to the rider

Nah - just doesn't follow.

If the helmet isn't there where does the energy that cracks the helmet go?

HarryCallahan wrote:

If the helmet isn't there where does the energy that cracks the helmet go?

Often some of the energy is lost to air resistance and some is transferred to the impact of whatever part of the body hits the ground instead of the smaller, lighter head which the body can now protect by tucking in.

I tell you what, strap a large half-pound weight to the outside of your elbow, then try walking around and see how many door frames and walls you hit that you usually avoid. That's not dissimilar to the effect of these crap commuter cycle helmets on a head.

Now if you're taking risks like racing or doing serious mountain biking or BMXing, then I can understand that you'd want a decent helmet, probably stronger than the junk sold to commuters, but that's a different calculation to everyday cycling.

a.jumper wrote:

HarryCallahan wrote:

If the helmet isn't there where does the energy that cracks the helmet go?

Often some of the energy is lost to air resistance and some is transferred to the impact of whatever part of the body hits the ground instead of the smaller, lighter head which the body can now protect by tucking in.

That's great advice.
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For Turtles!

HarryCallahan wrote:

If the helmet isn't there where does the energy that cracks the helmet go?

It gets focussed into a raw concentrated form of idiocy that's then handed out to people like you.

Tell me, how much energy, in J or kCal if you like, is required to create a few square inches of crack in expanded polycarbonate?

nuclear coffee wrote:

HarryCallahan wrote:

If the helmet isn't there where does the energy that cracks the helmet go?

It gets focussed into a raw concentrated form of idiocy that's then handed out to people like you.

Tell me, how much energy, in J or kCal if you like, is required to create a few square inches of crack in expanded polycarbonate?

Do you know there's a difference between cracking and instantaneous disintegration?

The damaged, compressed, helmet structure sat between the head and hard ground (wall, pole, windscreen etc) and took some of the impact.

Go do a simple experiment using a hammer, a helmet and your head. Which hurts more, with or without helmet?

HarryCallahan wrote:

nuclear coffee wrote:

HarryCallahan wrote:

If the helmet isn't there where does the energy that cracks the helmet go?

It gets focussed into a raw concentrated form of idiocy that's then handed out to people like you.

Tell me, how much energy, in J or kCal if you like, is required to create a few square inches of crack in expanded polycarbonate?

Do you know there's a difference between cracking and instantaneous disintegration?

The damaged, compressed, helmet structure sat between the head and hard ground (wall, pole, windscreen etc) and took some of the impact.

Go do a simple experiment using a hammer, a helmet and your head. Which hurts more, with or without helmet?

MSCi in materials science, so yes, I do. The post just above this one is pretty relevant. Unlike your answer, which *completely* ignored my question, suggesting you don't have a clue.

nuclear coffee wrote:

HarryCallahan wrote:

nuclear coffee wrote:

HarryCallahan wrote:

If the helmet isn't there where does the energy that cracks the helmet go?

It gets focussed into a raw concentrated form of idiocy that's then handed out to people like you.

Tell me, how much energy, in J or kCal if you like, is required to create a few square inches of crack in expanded polycarbonate?

Do you know there's a difference between cracking and instantaneous disintegration?

The damaged, compressed, helmet structure sat between the head and hard ground (wall, pole, windscreen etc) and took some of the impact.

Go do a simple experiment using a hammer, a helmet and your head. Which hurts more, with or without helmet?

MSCi in materials science, so yes, I do. The post just above this one is pretty relevant. Unlike your answer, which *completely* ignored my question, suggesting you don't have a clue.

To be fair, I think Harry might have been saying much of what I was, but in a different way. I might well be wrong about that mind.

fukawitribe wrote:

nuclear coffee wrote:

HarryCallahan wrote:

nuclear coffee wrote:

HarryCallahan wrote:

If the helmet isn't there where does the energy that cracks the helmet go?

It gets focussed into a raw concentrated form of idiocy that's then handed out to people like you.

Tell me, how much energy, in J or kCal if you like, is required to create a few square inches of crack in expanded polycarbonate?

Do you know there's a difference between cracking and instantaneous disintegration?

The damaged, compressed, helmet structure sat between the head and hard ground (wall, pole, windscreen etc) and took some of the impact.

Go do a simple experiment using a hammer, a helmet and your head. Which hurts more, with or without helmet?

MSCi in materials science, so yes, I do. The post just above this one is pretty relevant. Unlike your answer, which *completely* ignored my question, suggesting you don't have a clue.

To be fair, I think Harry might have been saying much of what I was, but in a different way. I might well be wrong about that mind.

Yes, you provided useful information. He asked a rather stupid leading question and looked smart.

nuclear coffee wrote:

HarryCallahan wrote:

nuclear coffee wrote:

HarryCallahan wrote:

If the helmet isn't there where does the energy that cracks the helmet go?

It gets focussed into a raw concentrated form of idiocy that's then handed out to people like you.

Tell me, how much energy, in J or kCal if you like, is required to create a few square inches of crack in expanded polycarbonate?

Do you know there's a difference between cracking and instantaneous disintegration?

The damaged, compressed, helmet structure sat between the head and hard ground (wall, pole, windscreen etc) and took some of the impact.

Go do a simple experiment using a hammer, a helmet and your head. Which hurts more, with or without helmet?

MSCi in materials science, so yes, I do. The post just above this one is pretty relevant. Unlike your answer, which *completely* ignored my question, suggesting you don't have a clue.

Well back to your irrelevant question then.

You could drive a steam roller over helmet foam and not crack it in the sense of large visible separations. Concentrated force on a section can cause separation at the edge, say a high heal creating a sharp indentation. Then again pushing a cricket ball into it won't necessarily cause separation because the impact force reduces smoothly over a distance.

In the end it's just a dumb irrelevant question which doesn't have a precise answer as requested because there are too many unknowns.

And also, as an MSc whatever, surely you know that an impact is measured in terms of FORCE and PRESSURE not energy??

The foam is there to lengthen the deceleration by way of compression, so our concern is compressibility, thickness, not "what 'energy' is required to crack it" .

HarryCallahan wrote:

nuclear coffee wrote:

HarryCallahan wrote:

nuclear coffee wrote:

HarryCallahan wrote:

If the helmet isn't there where does the energy that cracks the helmet go?

It gets focussed into a raw concentrated form of idiocy that's then handed out to people like you.

Tell me, how much energy, in J or kCal if you like, is required to create a few square inches of crack in expanded polycarbonate?

Do you know there's a difference between cracking and instantaneous disintegration?

The damaged, compressed, helmet structure sat between the head and hard ground (wall, pole, windscreen etc) and took some of the impact.

Go do a simple experiment using a hammer, a helmet and your head. Which hurts more, with or without helmet?

MSCi in materials science, so yes, I do. The post just above this one is pretty relevant. Unlike your answer, which *completely* ignored my question, suggesting you don't have a clue.

Well back to your irrelevant question then.

You could drive a steam roller over helmet foam and not crack it in the sense of large visible separations. Concentrated force on a section can cause separation at the edge, say a high heal creating a sharp indentation. Then again pushing a cricket ball into it won't necessarily cause separation because the impact force reduces smoothly over a distance.

In the end it's just a dumb irrelevant question which doesn't have a precise answer as requested because there are too many unknowns.

And also, as an MSc whatever, surely you know that an impact is measured in terms of FORCE and PRESSURE not energy??

The foam is there to lengthen the deceleration by way of compression, so our concern is compressibility, thickness, not "what 'energy' is required to crack it" .

Too much stupid to bother replying to everything.

Look up "impact test" about anywhere really. Energy is absolutely relevant, as is stress. And no, you absolutely cannot drive a steamroller over a helmet and have it survive, idiot.

nuclear coffee wrote:

HarryCallahan wrote:

nuclear coffee wrote:

HarryCallahan wrote:

nuclear coffee wrote:

HarryCallahan wrote:

If the helmet isn't there where does the energy that cracks the helmet go?

Tell me, how much energy, in J or kCal if you like, is required to create a few square inches of crack in expanded polycarbonate?

Too much stupid to bother replying to everything.

Look up "impact test" about anywhere really. Energy is absolutely relevant, as is stress. And no, you absolutely cannot drive a steamroller over a helmet and have it survive, idiot.

Just quickly.

What is the answer to your question?