Crash and helmet

[mattheus]

Look at a breakdown of doom/distance ratios by road type

That's a great phrase!

[tim-b]

(Let's gloss over the absolute twaddle you've written about evolution and cycling skills ...)

Oh dear...

[dmrcycle]

I see a LOT of pictures of cracked helmets - so remember this is barely absorbing any energy at all. Think of car CRUMPLE zones - they are not made out of brittle materials, deliberately!

Not true, crumple zones are to decelerate gradually and plus its hard to make a steel car shatter. A cracked helmet is absorbing energy (and a significant amount to cause fracture in plastic and polystyrene). Its the basic physics of energy.

... which you don't seem to understand. Quite common in these discussions, please don't feel bad.

I'll try to put this simply; if you crack a protective helmet, it has not reduced* the decelerations involved. It is not crumpling. A thick cushion would be better protection. In fact thick cushions would be good protection for your head against blunt trauma, even though I haven't seen any tests for me to quote at you

*Or perhaps only negligibly!

Sorry you don't understand physics and energy. Don't feel bad. Its about energy absorption and converting kinetic energy into another form. I have studied this and did a dissertation on energy impact in my physics degree. It was high velocity impacts of asteroids but the physics is the same. A cushion would help as it converts kinetic energy into heat but as its so soft it would soon not be compressible. I just find it amazing that there are qualified scientists and engineers working with simulations and various materials at the helmet companies and regulatory bodies yet you suggest a cushion is a better solution. Leave it to the experts buddy. They know more.

[mattheus]

You can flash your credentials all you like: I do know how energy conversion works (you're not the only cyclist that went to school my friend), and I know that a cracked helmet isn't doing a lot for you.

(and remember, brain damage is about movement of the brain relative to your skull and other tissues - so velocities (linear and rotational), accelerations and the like* are important; energy isn't the most important thing here.)

Have you read what the helmet makers say about their effectiveness against concussions? I presume you trust their data more than mine still?

*EDIT: I forgot one, sorry! I forget momentum, I hope (s)he forgives me. As you will know from your collision studies, momentum is conserved even when energy is being chucked around into noise and heat etc.)

[DevonDamo]

I never wear a helmet when riding on the road, and I'm violently opposed to mandating helmet wearing, and that's the reason I'm really thankful that this sub-forum has such a small audience. If I were campaigning to make helmet use mandatory, my first action would be to direct as many influential policy-makers as possible to this forum so they could read some of the assertions being made, e.g. that if your head is about to be hit hard by a blunt or sharp object, then having a helmet on your head won't offer any protection and may even make matters worse. This sort of daftness is simply people getting confused by the more plausible assertion that if you fall off your bike, a helmeted (wider) head is more likely to hit the ground, and in doing so may result in turning moment etc. If you want to convince people that your position is wrong, then making assertions that sound ludicrous is a great starting point.

You don't need to make these sort of assertions to argue against helmet use. There's strong statistical data to show that mandatory helmet laws lead to significant reduction in the numbers of people cycling, which results in a net increase in the number of people in hospitals and cemeteries - through strokes and heart attacks etc. I've read some of the 'helmets make head injuries worse' evidence, and what I've seen is that it's entirely dependent on the specific nature of the impact. To try and repackage this as 'you'd be better off without a plant-pot on your head when someone drops a bowling ball on it' may score points inside your echo chamber, but will have Joe Public thinking you're barking mad.

[Jdsk]

I never wear a helmet when riding on the road, and I'm violently opposed to mandating helmet wearing, and that's the reason I'm really thankful that this sub-forum has such a small audience. If I were campaigning to make helmet use mandatory, my first action would be to direct as many influential policy-makers as possible to this forum so they could read some of the assertions being made, e.g. that if your head is about to be hit hard by a blunt or sharp object, then having a helmet on your head won't offer any protection and may even make matters worse. This sort of daftness is simply people getting confused by the more plausible assertion that if you fall off your bike, a helmeted (wider) head is more likely to hit the ground, and in doing so may result in turning moment etc. If you want to convince people that your position is wrong, then making assertions that sound ludicrous is a great starting point.

You don't need to make these sort of assertions to argue against helmet use. There's strong statistical data to show that mandatory helmet laws lead to significant reduction in the numbers of people cycling, which results in a net increase in the number of people in hospitals and cemeteries - through strokes and heart attacks etc. I've read some of the 'helmets make head injuries worse' evidence, and what I've seen is that it's entirely dependent on the specific nature of the impact. To try and repackage this as 'you'd be better off without a plant-pot on your head when someone drops a bowling ball on it' may score points inside your echo chamber, but will have Joe Public thinking you're barking mad.

It isn't only Joe Public. I've described the nature of some of the arguments on this site to many other people who ride bikes and a fair number who set health policy. Ludicrous and barking mad are fair descriptions of common responses.

But it's possible to have a rational informed discussion on the subject. The ground rules might be something like this:
* Separate the many different questions and discuss them in a way that clearly identifies which question it is
* Use evidence-based methods: say what's known and what isn't known and quote your sources.

I'd like to add:
* Find areas of agreement as well as areas of disagreement
but I no longer expect that to happen here.

Jonathan

[mattheus]

some of the assertions being made, e.g. that if your head is about to be hit hard by a blunt or sharp object, then having a helmet on your head won't offer any protection and may even make matters worse. This sort of daftness is simply people getting confused by the more plausible assertion that if you fall off your bike, a helmeted (wider) head is more likely to hit the ground, and in doing so may result in turning moment etc. If you want to convince people that your position is wrong, then making assertions that sound ludicrous is a great starting point.

I've frequently posited your bolded statement. Helmet Enforcers generally rubbish it on threads like these.

Do you have a citation - on THIS thread - for your first claim?

"... some of the assertions being made, e.g. that if your head is about to be hit hard by a blunt or sharp object, then having a helmet on your head won't offer any protection"
Who said this?

[tim-b]

Helmet Enforcers generally rubbish it on threads like these

Who are the "Helmet Enforcers"?
I don't think that we have these in the UK

[tim-b]

Have you read what the helmet makers say about their effectiveness against concussions?

What have the helmet makers said about the effectiveness of cycle helmets against concussions?

[mattheus]

Helmet Enforcers generally rubbish it on threads like these

Who are the "Helmet Enforcers"?
I don't think that we have these in the UK

You're reading this thread, right? We have highly vocal helmet compulsion fans right here (some of whom try to justify their stance by throwing dubious reasoning around.)

Same as almost every other internet helmet thread.

Then there are the people actually enacting these rules in their clubs/associations. Quite a few of those - power gone to their heads, mainly.

[Jdsk]

...
You're reading this thread, right? We have highly vocal helmet compulsion fans right here...
...

Please could you give an example of that in this thread.

Thanks

Jonathan

[mattheus]

...
You're reading this thread, right? We have highly vocal helmet compulsion fans right here...
...

Please could you give an example of that in this thread.

Thanks

Jonathan

search.php?author_id=58309&sr=posts

(go to his 6th post on the forum)

[Jdsk]

...
You're reading this thread, right? We have highly vocal helmet compulsion fans right here...
...

Please could you give an example of that in this thread.

search.php?author_id=58309&sr=posts

(go to his 6th post on the forum)

I think that's a reference to dmrcycle, whose sixth post is:
viewtopic.php?p=1724495#p1724495
which is about spray cans.

Did you mean the sixth post in this thread?
viewtopic.php?p=1715874#p1715874

Probably easiest if you could give a link to the individual post...

Thanks

Jonathan

[mattheus]

You're counting in the wrong direction - the forum lists most recent posts first!
It's this one:
viewtopic.php?p=1724500#p1724500

[Jdsk]

...
You're reading this thread, right? We have highly vocal helmet compulsion fans right here...
...

Please could you give an example of that in this thread.

...
It's this one:
viewtopic.php?p=1724500#p1724500

Thanks.

That isn't in this thread.

Jonathan