helmet ventilation?

"(PeteCresswell)" wrote in message
...
Per Ron Hardin:
t's a 1975 Bell mushroom helmet, a pleasant sun-reflecting white with
rigid
white styrofoam insulation, so it takes off all the radiative solar heat.
That's
a huge benefit. Riding without it is much hotter, very noticeable.

Now you've got me thinking it's the color. Mine's a dark-ish grey.
Maybe a little strategically-applied spray paint...


Better yet, get some aluminum foil. It's easy to mold and with a bit of 3M
spray tack, you can stick it to the helmet.

An added plus: aliens won't be able to read your thoughts anymore.

Chris - firmly tongue in cheek

Just zis Guy, you know? wrote:
It's a good question, actually - I don't know to what extent the body
is able to compensate for the reduced cooling. As far as I understand
it the scalp plays the major part in cooling the head, and there is
evidence in respect of cricketers that helmet-induced heating impairs
reactions. I think there are probably as many unknown unknowns as
known unknowns here.

There is a lot of data on the opposite side. That is by keeping the
head warm (via a hat)there is a large positive effect on staying warm.
In most cold weather ative sports competitors seem to worry most about
losing heat from the head, hands, and feet. And as a result if those
areas are covered it seems that they can use relativley light clothing
(sans a big wind chill effect) everywhere else as long as activity
level stays high.

So, I would think that this can be extrapolated to guessing that in
hot weather that if the head isn't allowed to cool that overall body
temp may rise as a result.

Per Ron Hardin:
The cooling effect change isn't noticeable. The huge cooling is from sun
shielding, and that's compared even to wearing no helmet.

As long as the vents are plugged, wear a baseball cap under the helmet to
get a nice visor, very handy in cold wind or rain, as well as sun.

Where/what time of year are you riding?

I'm in Southeastern Pennsylvania (USA) and in July/August I wind up taking the
thing off for 15-20 minutes at a time just because it feels soooooooo good to
have the cool wind in my hair instead of sweat running down my glasses and
feeling like my brains are gonna poach like an egg.

Giro Zen.

Somewhere on the web, there's an anti-helmet site whose argument is based in
part on injury reduction vs reduced health benefits from fewer people riding
after some sort of manditory helmet law was passed in Australia.

I'm mostly a helmet zealot, but I can also see his side of the argument.


--
PeteCresswell

Someone at RMIT published research on this in Bicycling Australia a couple
of years back. Can't remember the exact details, but I think they stuck
temperature sensors in/on a headform, heated it, then blew air across and
measured the rate of cooling with various helmets (and also with no helmet
as a comparison). There was no correlation between price and and how well
the helmet allowed cooling to take place. Some of the cheap helmets with
what appeared to be poor ventilation were near the top of the list and some
of the expensive ones which were mostly slots were near the bottom. And the
best of the helmets allowed cooling as rapidly as a bare head.

Nick

"C.J.Patten" wrote in message
...
I won't get in to a helmet debate. I wear one, reasons irrelevant for this
thread.

My question has to do with vents.

My current helmet is a Giro Indicator. This wasn't an expensive helmet but
it fits well.

When you spend 5 times as much to get something like a Giro Atmos (i
gather they use it on the tour?) is the ventilation that much better?
Would you notice your head staying that much cooler?

Well heck, that's a tease! I gotta find that study!
Thanks for that though... good to know.


"Nick Payne" wrote in message
...
Someone at RMIT published research on this in Bicycling Australia a couple
of years back. Can't remember the exact details, but I think they stuck
temperature sensors in/on a headform, heated it, then blew air across and
measured the rate of cooling with various helmets (and also with no helmet
as a comparison). There was no correlation between price and and how well
the helmet allowed cooling to take place. Some of the cheap helmets with
what appeared to be poor ventilation were near the top of the list and
some of the expensive ones which were mostly slots were near the bottom.
And the best of the helmets allowed cooling as rapidly as a bare head.

Nick

"C.J.Patten" wrote in message
...
I won't get in to a helmet debate. I wear one, reasons irrelevant for this
thread.

My question has to do with vents.

My current helmet is a Giro Indicator. This wasn't an expensive helmet
but it fits well.

When you spend 5 times as much to get something like a Giro Atmos (i
gather they use it on the tour?) is the ventilation that much better?
Would you notice your head staying that much cooler?

On Wed, 13 Jul 2005 08:58:53 -0400, "C.J.Patten"
wrote:

My question has to do with vents.

My current helmet is a Giro Indicator. This wasn't an expensive helmet but
it fits well.

When you spend 5 times as much to get something like a Giro Atmos (i gather
they use it on the tour?) is the ventilation that much better? Would you
notice your head staying that much cooler?

The only benchmark that I consider important in this regard is "Do I
have enough venilation with the helmet I have now?" If the answer is
"yes", then in my opinion, no further expenditure is worthwhile.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

Per Ron Hardin:
t's a 1975 Bell mushroom helmet, a pleasant sun-reflecting white with rigid
white styrofoam insulation, so it takes off all the radiative solar heat. That's
a huge benefit. Riding without it is much hotter, very noticeable.

Now you've got me thinking it's the color. Mine's a dark-ish grey.
Maybe a little strategically-applied spray paint...
--
PeteCresswell

On Wed, 13 Jul 2005 17:42:19 -0400, "C.J.Patten"
wrote:


"(PeteCresswell)" wrote in message
.. .
Per Ron Hardin:
t's a 1975 Bell mushroom helmet, a pleasant sun-reflecting white with
rigid
white styrofoam insulation, so it takes off all the radiative solar heat.
That's
a huge benefit. Riding without it is much hotter, very noticeable.

Now you've got me thinking it's the color. Mine's a dark-ish grey.
Maybe a little strategically-applied spray paint...


Better yet, get some aluminum foil. It's easy to mold and with a bit of 3M
spray tack, you can stick it to the helmet.

An added plus: aliens won't be able to read your thoughts anymore.

Chris - firmly tongue in cheek

Dear Chris,

Actually, the thin metal domes amplify the weak signal
sufficiently to be received by our instruments at a muc
greater distance and allow us in turn to reach and control a
much wider audience.

Kang & Kodos

Per C.J.Patten:
that's a tease!

Amen.
--
PeteCresswell

Booker C. Bense wrote:

IMHO, the big difference between cheap and $$$ is ventilation
and weight.

Don't forget protection.

If you pay $130 for a helmet, it's guaranteed to keep a decapitated
head under 300 gees in a 14.01 mph impact.

Whereas if you pay $15 for a helmet, that decapitated head may not hit
300 gees until, oh, 15 or 16 mph.

OK, it's not a big difference. And nobody will ever tell you the exact
numbers. But the difference is there. The more you pay, the less
protection you get.

- Frank Krygowski