Ken <
[email protected]> wrote in message news:<
[email protected]>...
> Fraggle <
[email protected]> wrote in
news:Xns93DC11C9146F5Fragglerock1 @195.129.110.200:
> > The protectiveness of helmets degrades quite fast, you should replace your helmet every couple
> > of years as a matter of course
>
> Do you work for a helmet company?
Check my last post
So here is my explanation, which I cannot back up as google is not providing the goods, so if you
don't believe me fine.
Bike helmets work by crushing air filled polystyrene the hard shell does no cushioning and if the
styrene cracks it has much less power to absorb your heads momentum (I guess because the fragments
of helmet are light and just move out the way)
over a period of years the nature of the material degrade such that cracking is more likely than
crushing, thus the helm is less efficient. Dropping your helm from even a short height is somewhat
likely to start cracks in the styrene, which again will make cracking of the shell more likely
than crushing.
The hard heavy shell has no real protective benefit, which is why they have been removed in more
modern helms.
Helms are cheap and easy to replace, you brain is less so.
As I say believe me or don't. I won't reply again, as there are enough helmet threads on Usenet
as it is
Fragg