more helmet lies

[David Martin]

BARRY wrote:
> All a cycle helmet can give you is additional protection to your
> head.....

Not true. A cycle helmet can also give you additional risk of serious
head injury through two clear mechanisms and additional risk of neck injury.

Head injury mechanism 1: helmets increase the effective size of the
head, turning near misses into glancing blows at the peripherary of the
skull.
HI mech 2: blows tangentical to the head (rather than in line with the
centre of motion) will cause rotational acceleration. You need 50 times
less rotational acceleration to get a permanent brain injury than from a
direct linear blow. Helmets can increase the rotational component of an
impact, increasing the likelyhood of HI, and are only designed to cope
with linear blows.

Neck injury: The increased size and weight of the head with a helmet on
increases the risk of neck injury (whiplash type).

So helmets do protect against minor linear blows and against scratches
and bruises, but the payoff is that they may kill you as well. You
really don't know which is more likely without looking at full
population studies. I'd suggest you do so.

...d

 

[Al C-F]

On Wed, 29 Dec 2004 16:13:29 +0000, Tony B
<[email protected]> wrote:

>So, am I wrong to think my m/c helmet is useful, whereas my bicycle
>helmet is not?

Interesting question. I'm sure I remember reading that the m/c helmet
law saw a rise in the number of injured but surviving motorcyclists -
so rather than being killed, they get to live their lives in
wheelchairs.

Has anyone got any evidence one way or the other?

 

[Zog The Undeniable]

Al C-F wrote:

> On Wed, 29 Dec 2004 16:13:29 +0000, Tony B
> <[email protected]> wrote:
>
>
>>So, am I wrong to think my m/c helmet is useful, whereas my bicycle
>>helmet is not?
>
>
> Interesting question. I'm sure I remember reading that the m/c helmet
> law saw a rise in the number of injured but surviving motorcyclists -
> so rather than being killed, they get to live their lives in
> wheelchairs.
>
> Has anyone got any evidence one way or the other?

I believe the impact speed a m/c helmet is designed for isn't very
different to the speed for a bicycle helmet. This means that either
bicycle helmets are exceptionally good considering their weight and
ventilation, or motorcycle helmets are very poorly designed!

 

[Peter Keller]

On Wed, 29 Dec 2004 17:18:25 +0000, Zog The Undeniable wrote:


>
> I believe the impact speed a m/c helmet is designed for isn't very
> different to the speed for a bicycle helmet. This means that either
> bicycle helmets are exceptionally good considering their weight and
> ventilation, or motorcycle helmets are very poorly designed!

The energy available to mangle you in a crash is proportional to the
square of the impact velocity (approx.)
Therefore, if a bicycle helmet provides some protection at up to 20kph,
for a motorcycle helmet to provide equivalent protection at up to 40kph it
would need to have FOUR times the energy-absorbent value of a bicycle
helmet.
To say nothing of the effects of these vastly increased forces on the neck!

Peter

--
If you are careful enough in life, nothing bad -- or
good -- will ever happen to you.