D
David Kerber
Guest
In article <[email protected]>, "frkrygow" <"frkrygow"@omitcc.ysu.edu> says...
> David Kerber wrote:
>
> > For hard shell, I was also thinking of the ones BMX riders wear. I don't remember ever seeing a
> > bare polystyrene helmet. The slick outer covering on current helmet designs seems unlikely to
> > "catch" on pavement unless some kind of object (sewer grate, curb edge, car mirror?) grabs one
> > of the ventilation holes.
>
> I'm not convinced.
I'm not either, but that's my gut feeling. IMO it certainly merits some research.
> First, I have seen bare polystyrene helmets. They were popular in the mid '80s, as I recall. Some
> were sold with gossamer-thin fabric coverings, claimed to hold the helmet pieces together if it
> shattered. Worries of neck injuries took them off the market, and at least some helmet promoters
> began saying you should buy a new one if that's what you had.
Makes sense to me.
> Today's helmets are mostly "microshell" - a thin (0.003") vacuum-formed plastic covering taking
> the place of the gossamer fabric or the hard shell. Less weight & less expense than a hard shell.
>
> But will 0.003" of relatively soft plastic keep the helmet from "catching" on the hard, rough-
> textured asphalt? Perhaps it might help a tiny bit, but I doubt it helps much.
Obviously depends on the characteristics of the plastic. If it's tear-resistant enough, it should do
the job, since it is certainly slick enough to slide if it stays intact.
....
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Dave Kerber Fight spam: remove the ns_ from the return address before replying!
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> David Kerber wrote:
>
> > For hard shell, I was also thinking of the ones BMX riders wear. I don't remember ever seeing a
> > bare polystyrene helmet. The slick outer covering on current helmet designs seems unlikely to
> > "catch" on pavement unless some kind of object (sewer grate, curb edge, car mirror?) grabs one
> > of the ventilation holes.
>
> I'm not convinced.
I'm not either, but that's my gut feeling. IMO it certainly merits some research.
> First, I have seen bare polystyrene helmets. They were popular in the mid '80s, as I recall. Some
> were sold with gossamer-thin fabric coverings, claimed to hold the helmet pieces together if it
> shattered. Worries of neck injuries took them off the market, and at least some helmet promoters
> began saying you should buy a new one if that's what you had.
Makes sense to me.
> Today's helmets are mostly "microshell" - a thin (0.003") vacuum-formed plastic covering taking
> the place of the gossamer fabric or the hard shell. Less weight & less expense than a hard shell.
>
> But will 0.003" of relatively soft plastic keep the helmet from "catching" on the hard, rough-
> textured asphalt? Perhaps it might help a tiny bit, but I doubt it helps much.
Obviously depends on the characteristics of the plastic. If it's tear-resistant enough, it should do
the job, since it is certainly slick enough to slide if it stays intact.
....
--
Dave Kerber Fight spam: remove the ns_ from the return address before replying!
REAL programmers write self-modifying code.