Cycle helmet broken in fall

This sub-forum all discussions about this "lively" subject. All topics that are substantially about helmets will be moved here, if not placed here correctly in the first place.
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[XAP]Bob
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Re: Cycle helmet broken in falle way to hospital I could see

Postby [XAP]Bob » 25 Nov 2014, 6:19pm

oneten wrote:Moreover, saying that without a helmet a rider would just suffer some surface some bruising and surface laceration seems as subjective and unscientific a prediction as saying that it saved a cyclist from a more severe head injury.

Not really, the OP described a classic failure mode of a helmet, with no suggestion of anything other than failure. Brittle failure of expanded polystyrene foam absorbs virtually no energy.

To absorb energy (which is how we prevent serious injuries) the EPF needs to compress - this is either plastic (leaving a compressed helmet shell) or it is elastic (returning to the previous thickness) which is very limited, it plays a very small role.

If I said that my seatbelt snapped and therefore saved my life in a minor crash you'd suggest that the seatbelt had failed, rather than doing any good...

I didn't even mention that the extra size and weight of the helmet may have contributed to the impact, nor that the very act of wearing the helmet may have influenced the approach speed and caused the fall in the first place.
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oneten
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Re: Cycle helmet broken in fall

Postby oneten » 25 Nov 2014, 8:23pm

MJR - as to the cause of the crash, it was really down to me. Partly a case of over familiarity with a daily commuting route coupled with failure to take prevailing conditions into account.I was approaching the junction and the onus was on me to give way to the taxi. Usually when I come out of this side road to turn left, the other road is relatively quiet and there is good visibility. I often just slow down a bit nip around the corner, if a car is approaching, it's easy to brake safely to give way. On this occasion I misjudged the greater braking distance on the wet road and the change of surface from tarmac to cobbles. So, really no-one else was to blame.

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jezer
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Re: Cycle helmet broken in fall

Postby jezer » 25 Nov 2014, 8:44pm

TonyR wrote:
jezer wrote:I think it shows the helmet did its job by absorbing the impact. Better a helmet that the head. I've wrecked two over the years in crashes, and on neither occasion did I realalise my head had hit the tarmac until I removed the helmet later. Of course they would be unlikely to help if hit by a motor vehicle, but in the more common crashes I'm convinced of the benefit.


Of course it could be that the only reason your head hit the tarmac was it was made a couple of inches bigger all round by the helmet.

You may be correct, but as an OAP who has been cycling since 1958, and now with slower reactions to you younger folk, I'll continue to wear a helmet. I remember wearing some sort of leather protection when racing in those days, and I don't think they offered anything as good as the helmets we have today.
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oneten
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Re: Cycle helmet broken in fall

Postby oneten » 25 Nov 2014, 9:38pm

Bob - I agree with what you say about the helmet material needing to be springy in order to absorb shock and of course this is limited with dense polystyrene. But the shell of a motorcycle helmet doesn't seem particularly yielding either. Likewise hard hats used in construction and other industry are also a 'hard' shell construction. I suppose the shock absorbsion property is due to the springy plastic sub structure suspended within the helmet shell.I don't think anyone questions the wisdom of crash helmets for motorcyclists or that of wearing hard hats on building sites. So why is there such a lot of skepticism about cycle helmets. Are we to conclude that cycle helmet manufacturers are somehow discredited or guilty of some elaborate scam offering expensive products that are just cosmetic with no real value from a safety point of view?

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Audax67
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Re: Cycle helmet broken in fall

Postby Audax67 » 25 Nov 2014, 9:48pm

Glad you're OK. The rest of this wrangle will be as fruitless as usual.
Have we got time for another cuppa?

kwackers
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Re: Cycle helmet broken in fall

Postby kwackers » 25 Nov 2014, 9:56pm

oneten wrote:I don't think anyone questions the wisdom of crash helmets for motorcyclists or that of wearing hard hats on building sites. So why is there such a lot of skepticism about cycle helmets. Are we to conclude that cycle helmet manufacturers are somehow discredited or guilty of some elaborate scam offering expensive products that are just cosmetic with no real value from a safety point of view?

Cycle helmets aren't motorcycle helmets - not by a long way.

Cycle helmets are tested for a ball impact at 12mph - your skull would protect you against that anyway.
Then there's the issue of brain damage, most (non penetrating) brain damage is due to diffuse axonal injuries which is caused by rapid rotation of the head - i.e. you bang your head and it 'grips' and is spun. Helmets potentially make this worse, the motorcycle helmet makers recognise this and test their products for it. Cycle helmet manufacturers don't - which is just as well because their construction makes it much worse.

In simple terms cycle helmets sell on the basis of 'common sense' rather than science. When was the last time you fell off your bike and had a lightweight round 'ball' hit your helmet square on at 12mph whilst your head was rigidly fixed in place?
Me neither.

beardy
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Re: Cycle helmet broken in fall

Postby beardy » 25 Nov 2014, 10:05pm

Are we to conclude that cycle helmet manufacturers are somehow discredited or guilty of some elaborate scam offering expensive products that are just cosmetic with no real value from a safety point of view?


Well, that isnt far enough from the truth to argue against.

and they arent the only ones at it!

http://www.fatallyflawed.org.uk/

irc
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Re: Cycle helmet broken in fall

Postby irc » 25 Nov 2014, 10:08pm

oneten wrote:.I don't think anyone questions the wisdom of crash helmets for motorcyclists or that of wearing hard hats on building sites. So why is there such a lot of skepticism about cycle helmets.


Motorbike helmets weigh about 1.5-2kg. Cycle helmets weigh 200 -300g. Which do you think will provide more protection?

Hard hats on building site are intended to protect the head from penetration injuries from small fast falling objects. Smaller forces than those involved when a person is in a crash.

As for cyclist V motorcyclists - my average touring speed in around 12-14mpg on the flat. A motorcyclist going 5x faster will generate 25x the impact forces in a crash. So unlike cyclists who are mostly going at not much more than running speeds the human skull evolved to cope with motorcyclists need all the help they can get.

Huge numbers on motorcyclists kill themselves in one vehicle accidents despite their helmets and leathers etc. Cyclists almost always survive accidents unless a motor vehicle is involved.

Not that I'm saying cycle helmets won't prevent some injuries and save the odd live but their benefits are hugely over stated by some lobby groups. If cycling was that dangerous why not walking helmets for pedestrians who have a similar fatality rate per mile?

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Re: Cycle helmet broken in fall

Postby mjr » 25 Nov 2014, 10:16pm

kwackers wrote:Cycle helmets are tested for a ball impact at 12mph - your skull would protect you against that anyway.

Not any more, most aren't. IIRC the ball impact is only in the Snell test, while the more common EuroNorm contains only a short-drop flat impact and a short-drop kerb-edge impact.

The rest of kwackers's points still hold though. Find how many cycle helmet manufacturers actually market on the protection they offer: most market on aerodynamics, comfort and looks... which I find just bizarre because they all look awful - and I thought that even when I wore one. Example: http://www.bellhelmets.com/en_eu/cyclin ... ional/muni

Another thing I've looked for a few times and not found is crash test dummy tests. Lots of disembodied heads and a couple of oddly-launched torsos. I wonder why...
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irc
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Re: Cycle helmet broken in fall

Postby irc » 25 Nov 2014, 10:16pm

oneten wrote:Are we to conclude that cycle helmet manufacturers are somehow discredited or guilty of some elaborate scam offering expensive products that are just cosmetic with no real value from a safety point of view?


Well I looked at Giro's website for their Synthe helmet. The blurb mentions "cooling power", light weight, streamlining, sunglass dock, etc. Seems mostly cosmetics to me. Nothing about the protection offered. No claims made there at all.

http://www.giro.com/eu_en/synthe/

DaveGos
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Re: Cycle helmet broken in fall

Postby DaveGos » 25 Nov 2014, 10:23pm

DId you go private . I had 2 falls on my head in a few weeks in the spring the first was a crank that was cross threaded by Halfords, and failed on a new bike in the first 24 hours , [rude word removed] still wont pay up , never buy a bike from Halfords , but that's another story . Was rushed 30 miles to A and E after being unconscious for 15 mins . Full A and E team awaiting me , but I seemed OK , No scan and they did not keep me in for observation despite living on my lonesome ( they are supposed to) . Second time trust my luck a crank on an older bike failed and I went down and just had bad concussion that time , got a taxi to the hospital that time. Waited in the queue and when called fell over dizzy . They gave me a leaflet explaining concussion this time . Did not keep me in - said I was young (56 lol) Not sure how you managed to get scans and on the same day, your A and E must have loads of money

Helmet cracked both times but still got concussion . I have not come to any conclusions. If I was wearing a boiled egg on my head it would also of cracked

To be fair I believe this is the type of accident that a helmet is designed for rather than say a vehicle impact

kwackers
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Re: Cycle helmet broken in fall

Postby kwackers » 25 Nov 2014, 10:31pm

DaveGos wrote:Helmet cracked both times but still got concussion . I have not come to any conclusions. If I was wearing a boiled egg on my head it would also of cracked

To be fair I believe this is the type of accident that a helmet is designed for rather than say a vehicle impact

Actually concussion is atypical of rotation. Forget all the nonsense about brains rattling around inside skulls - that was discredited decades ago. It's rapid rotation of the head aka 'whiplash'.
So basically if you were travelling forward and fell off, when your helmet/head hit the ground it 'cogged' on the floor and spun due to the forward movement. You probably saved yourself the loss of some skin but at the potential expense of concussion.

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Re: Cycle helmet broken in fall

Postby Bicycler » 25 Nov 2014, 10:49pm

Are we to conclude that cycle helmet manufacturers are somehow discredited or guilty of some elaborate scam offering expensive products that are just cosmetic with no real value from a safety point of view?

They are not necessarily expensive. You can pick one up in a supermarket for less than a tenner and that will be as likely to meet the relevant safety standards as a £120 Team Sky copy. So the latter is only 90odd% cosmetic :wink:

irc makes a very important point. The suspicious lack of safety claims from helmet manufacturers is enough to raise concerns. It is certainly not how manufacturers of important safety equipment normally behave. You may frequently hear that helmets "may save your life" but you never hear it from a helmet manufacturer

Also alarming is the way in which such a supposedly vital safety item is specced down to a price. If they are so vital, surely the R&D departments should be engaged in a development war to produce the highest standards of protection, not seeing how light and ventilated they can make something whilst still meeting the low industry standard they set themselves. The current European standard drawn up largely by manufacturers has been compared unfavourably to the independent 24 year old Snell B90 standard it replaced. Snell's updated B95 standard is widely regarded as the most rigorous for normal (ie. non-full face) cycle helmets. Few manufacturers have ever bothered to design or test their helmets to this standard and none are widely available in the UK. If you believe your product saves lives, why not insist upon meeting the highest standards? This wilful neglect rather suggests that protecting people's heads is someway down the list of priorities when it comes to making helmets.

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Re: Cycle helmet broken in fall

Postby TonyR » 25 Nov 2014, 11:16pm

oneten wrote: So why is there such a lot of skepticism about cycle helmets. Are we to conclude that cycle helmet manufacturers are somehow discredited or guilty of some elaborate scam offering expensive products that are just cosmetic with no real value from a safety point of view?


The scepticism is because first, cycling is no more dangerous than many other things we do without head protection - walking, taking a shower, descending stairs etc. So why single it out for helmet wearing?

Second, as one of our leading experts on risk said, the benefit, if there is one, is too modest to capture.

Third, everyone seems to wear one to protect them from traffic whereas its designed for no more than toppling off a stationary bike.

So given something that seems to confer no benefit for an activity that is no more dangerous than walking why wear one?

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Re: Cycle helmet broken in fall

Postby Vorpal » 25 Nov 2014, 11:22pm

oneten wrote:I don't think anyone questions the wisdom of crash helmets for motorcyclists


No? http://www.motorcycleforums.net/forum/p ... death.html
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