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 Post subject: Re:
PostPosted: Tue Jun 25, 2013 3:16 pm 
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Chopper1192 wrote:
And it's not just the energy absorbing/dissipating properties of the foam that are intended to reduce injury. There's one other prime method by which bonce potties reduce injury. So simple it's often overlooked, so effective process that even correctly shaped lid made from steel with no lining has the potential to produce the same effect, so obvious that even the most rabid anti lid campaigner forgets about it


Well, I didn't like to say this, but a helmet is great if you have an incipient bald spot.

Other than that: my guess is that you might mention slides and grazing. The problem with this is that it isn't part of the helmet spec, so abrasion resistance is usually very poor - the only way most cycling helmets will survive abrasion is if you have almost pressureless contact - which is actually very common, because the body is designed to protect the head in falls, but helmets extend it.

B95 cert helmets are a reasonable semi-exception to this because their testing includes the use of an anvil rather than a flat smooth surface.. but people like you never wear B95 cert helmets, because you rely on "common sense" (ie whatever you immediately think of - which is why I used quotes, 'cos it ain't the same) rather finding out facts.

If you want to see what a helmet that stands a chance of surving abrasion is like, then you have to look at motorcycling helmet. There is a reason they weigh about 4 times what a cycling helmet does!


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PostPosted: Tue Jun 25, 2013 4:14 pm 
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PurpleFrog wrote:
If your helmet cracked, it didn't work.

Oft cited, but alas incorrect.

The other main method by which a helmet works is distributing the load more widely across the skull. A (for sake of argument) 50kg impact over, say, 5 CM squares on the outside will, if the helmet fits well, be distributed over up to 600cm3 on the surface of the skull (depending on head size and point of impact) so instead of 10kg per cm3 at the exterior of the helmet, you might receive less than a 50rh of that per
Cm3 on the surface of your head. So, provided the parts of the helmet remain in situ the helmet will still function in distributing the impact force over a wider area after cracking, even fthough much of its energy absorbing function might be compromised.

This is one function of bonce potties that our 'helmet engineer' seems to have overlooked, and was initially illustrated during the 1950s when the US Governmet authorised the use of human cadavers in car crash experiments, including tests of safety systems and equipment. Absorbing energy is lovely, but dissipating it over a wider area than just the point of impact is also pretty effective.


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PostPosted: Tue Jun 25, 2013 4:34 pm 
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Sure, a helmet CAN prevent injuries or make them less severe. However it may make things worse.

There are plenty of people who suffered permanent brain damage because they fell off without a helmet.
However there also are several people who are in a wheelchair or in vegetative state because the helmet absorbed some of the impact and kept them alive.
If I get into such a serious crash (and spending most of my time in city traffic the chance of such a crash is much bigger), I'd rather not wear a helmet and get the full lethal blow.

It's all about taking chances. There's a chance the helmet saves you, there's a chance it makes things worse. You can't predict what kind of accident you'll have, so feel free to decide what kind of measures you'll want to take.
Just don't go telling people how they should protect themselves the way you do, because there simply isn't a right way for every possible scenario.


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PostPosted: Tue Jun 25, 2013 4:48 pm 
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I think lightweight cycle helmets are capable of protecting you from cuts, grazes and nasty bruises, but not much more. I think the worrying thing about them is the research that suggests vehicle drivers give less room to cyclists wearing helmets, perhaps because they sub-consciously perceive them as being less vulnerable. So helmeted cyclist might be more likely than an un-helmeted cyclists to be involved in a collision.

This is a bit like providing soldiers hi-vis bullet proof vests, offering them more protection from bullets, but making them more likely to be shot in the first place. :?

Other research shows that while helmet use has increased significantly, serious head injuries per capita have not, which suggest that if an impact is hard enough to cause a serious head injury, a cycle helmet has little or no effect.

In addition, we all know exactly how big our head is, we don't often get it wrong and instinctively duck under things, or move our head out of the way. Wearing a helmet makes your head bigger and messes up this instinct. Anecdotally: I was talking to a friend, who is a builder who said that when working in tight spaces he's always bumping his head while wearing a hard hat, whereas he hardly ever does when not wearing one.

Personally I think there's a need for a lot more research and I really don't want to see them become compulsory, because I think their efficacy is so debatable at present. Whereas, in places where they are compulsory, research suggests that the number of people using a bicycle drops by as much as 40% and that those that do continue to cycle are more at risk, because cyclists tend to be safer where other road users are more used to encountering them.

I'm also concerned by examples of reduced compensation payments to non helmet wearers and reduced penalties to those that injure them while there is such poor and inconsistent research into how effective they are. In addition, before reducing compensation, or penalties, you would have to decide on each individual case whether a helmet would have altered the outcome at all, after all if someone gets a broken leg, but no head injury, whether or not they are wearing a helmet is surely not significant.


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PostPosted: Tue Jun 25, 2013 4:52 pm 
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i see it never changes round here. Mention wearing helmets or not and it 'kicks' off Wear one if you want. Just don't tell me to.


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PostPosted: Tue Jun 25, 2013 5:35 pm 
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Helmets are gay.

I don't know what the rest of you are doing but any time I come off a bike it's my hands that take most of the impact. Actually it was my hip the last time as I lost grip in a damp concrete skatepark but the point is the same. Should I be wearing full body armour for pootling around town? Should pedestrians wear helmets in case of being struck by cars? Should some people get off their high horse about the supposed merits of polystyrene hats?

Plus they look absolutely ridiculous.


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PostPosted: Tue Jun 25, 2013 5:42 pm 
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The completely pro-helmet Nazis might point out that dribbling all the time because of a brain injury looks pretty stupid too.

Guys, lets live and let live. I wear a lid but I'm not insane enough to think it renders my noggin invulnerable to misfortune, so I still exercise common sense and caution. If you don't want to wear one then that's fine by me completely - why should I stick my nose into your own habits and peccadilloes?

I can't understand why people get so polarised and rabid over it. Why does the humble Giro turn otherwise normal, decent folk into slavering axe wielding loons?


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 Post subject: Re: Re:
PostPosted: Tue Jun 25, 2013 6:08 pm 
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PurpleFrog wrote:
...There is a reason they weigh about 4 times what a cycling helmet does!


because the likely impact speed is likely to be [at least] 4 times faster?

or because you'll slide [at least] 4 times as far?


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PostPosted: Tue Jun 25, 2013 6:15 pm 
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technodup wrote:
Helmets are gay.

I don't know what the rest of you are doing but any time I come off a bike it's my hands that take most of the impact. Actually it was my hip the last time as I lost grip in a damp concrete skatepark but the point is the same. Should I be wearing full body armour for pootling around town? Should pedestrians wear helmets in case of being struck by cars? Should some people get off their high horse about the supposed merits of polystyrene hats?

Plus they look absolutely ridiculous.



agree


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 Post subject: Re:
PostPosted: Tue Jun 25, 2013 6:33 pm 
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Chopper1192 wrote:
- romantic dinner with The History Man for the first person to guess.



Just had one of those. :wink:

Didn't have a helmet on my purple chopper.


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