Esmail Bonakdarian wrote:
>
> Frank Krygowski wrote:
> >
> > Esmail Bonakdarian wrote:
> > >
> > >
> > > However, after all these years the styrofoam (?) material is supposed to deteriorate and lose
> > > some (or all?) of it's properties that make it an absorbent material.
> >
> > Why do you think that?
>
> Hi Frank,
>
> My statement is based on what I have been told repeatedly by other cyclists. And friends working
> in bikestores. Not all of them were trying to sell me some helmets
>
> Seems to me I've read this also in the product literature, but I couldn't quote any sources.
>
> Why, does this not agree with what you know? I thought this was a pretty common knowlegde? Not an
> urban myth, is it? It does feel like the styrofoam has gotten more brittle/harder over the years.
Except for unusual circumstances, it's almost certainly an urban myth.
Some helmet manufacturers (Bell, for one) said that you should replace your helmet every three years
because of possible degradation of the foam. Obviously, they had an economic interest in promoting
the myth. The myth was picked up by some of the helmet proselytizers, passed around with great
sincerity, and has now been repeated so often that it's hard to convince people it's false. (This is
_exactly_ like the myth that helmets prevent 85% of head injuries, BTW.)
I've found only one mention of an actual test of an ancient helmet. The impact test detected no
degradation on a helmet that was well over ten years old. And if you think about it, this is
logical. Assuming you don't store your helmet in the closet with your opened bottles of acetone,
your helmet actually lives a soft life. Right now it's probably in your basement or closet,
protected from sunlight.
Sunlight or other UV will eventually affect styrofoam, but the main mass of the styrofoam is
shielded from sunlight by the thin plastic shell. Besides, few cyclists ride more than 2500 miles
per year. Even if you do that and your average speed is only 10 mph, that's just 250 hours per year
of outdoor exposure (probably much less). It's nothing like the situation for a thin styrofoam
coffee cup you see sitting in the gutter
- and those survive for years.
In any case, the supposed degradation has not been demonstrated by any test. And Bell no longer says
their helmets will degrade in three years
- probably on the advice of their lawyers! Instead, they now (last I checked) suggest you replace it
every three years to take advantage of advances in styling and new design features.
Yeah, right! As someone once posted here, a company manufacturing
cast iron door stops might say the same thing!
> Safetly is really my primary concern, so if I wear a brain bucket, I'd like it to be as effective
> as possible.
First, if you want it to be "as effective as possible," get the cheapest, heaviest, least-ventilated
helmet you can find. More expensive helmets actually cut closer to the lower limit of the impact
standards, in an effort to reduce weight and increase ventilation.
Second, you'd do well to remember that the protection afforded by the impact standards is very
slight indeed. Helmets are certified by a test that simulates a disembodied head falling about six
feet onto a hard surface. The impact speed is about 14 mph, and again, there's no body mass behind
the headform in the test. In a real crash, the limited protection of a helmet is very easily
exceeded. And helmets can't be made significantly more effective with present technology, because
they'd be too uncomfortable to cycle in.
(It's probably because of this that helmets have made no apparent difference in head injury deaths
and serious injuries of cyclists in the general population. But that's almost never publicized.)
Third, please keep in mind that, despite all the hype to the contrary, cycling is NOT especially
risky regarding serious head injuries. The only comparative data I've been able to find (in years of
reading & research) said that the risk of serious head injury, per hour, on a bike is almost exactly
the same as it is inside a car. That's despite seat belts and air bags.
50% of head injury fatalities happen inside cars. 40% happen in falls around the home. Less than 1%
happen on bikes. It's not as bad as they'd have you believe.
Finally, if you do wear a helmet, you'd do well to pretend it's not there. Many researchers believe
helmets lead people to take risks they wouldn't otherwise take because they feel protected; when a
crash occurs, they find the protection isn't so significant! Keep telling yourself: "It's only a 14
mph helmet." It'll make you more careful.
--
Frank Krygowski
[email protected]
