On 2019-08-05 21:55, Andre Jute wrote:
On Tuesday, August 6, 2019 at 2:10:34 AM UTC+1, Sir Ridesalot wrote:
On Monday, August 5, 2019 at 8:41:29 PM UTC-4, Andre Jute wrote:
On Monday, August 5, 2019 at 9:29:26 PM UTC+1, Tom Kunich wrote:
On Monday, August 5, 2019 at 1:33:00 AM UTC-7, Andre Jute
wrote:

Somebody on my ride was saying only the other day that
crashes at our age are so much more consequential. Though
they were talking about breaking a hip, I thought of that
when a couple of days later I fell while dismounting from my
bike (I hooked the mixte bar between my foot and its heel)
and landed so heavily that the deep dent in my helmet looks
like the most dangerous accident I've had in 30 years of
cycling -- from a standstill! The helmet saved me from a gash
on the head, painful stitches, and perhaps even a concussion.
That's definitely worth its price.

Andre Jute Not an old crock

Modern safety helmets reduce concussions not by softening the
blow via cushioning with the Styrofoam but by fracturing and
breaking via the "vent" holes in the helmet. I have a Bontrager
Wavecell helmet and it has a lot less vents for two reasons -
1. Unlike Styrofoam air passes rather freely though the open
core material and 2. you have to have the Wavecell material
covering most of your head to have the expected effect.

So my helmet isn't wrecked by the impact-dent?

Separate question. That helmet is actually pretty old, being on
its third bike. Is there a natural raging process (embrittling?)
of helmet materials that requires helmets to be replaced after x
time?

Andre Jute

I think that aging of the foam in a helmet depends on t he foam
material itself plus incidentals such as exposure to sunlight
(UVA/UVB rays)bumps it has suffered and even exposure to sweat. I
have an old hard-shell Vetta helmet here that appears to be in mint
condition. I guess it'd take a microscopic examination of the
underlying foam section to tell if the foam has deteriorated.

Manufacturers like to sell helmets and also protect themselves from
litigation and thus many helmet manufacturers tell customers to
replace the helmet every five years or some other number of years
and also to replace the helmet if it has suffered a hard knock or
fall.

Cheers

Thanks, Ridealot. I'll inspect the outside shell under a strong
light and magnification for cracks. None are visible with the naked
eye.


In the UK that may not be such a big deal but here in sunny California I
had to retire a helmet because the UV content of the sun light started
to embrittle the shell. It was only about three years old.

--
Regards, Joerg

http://www.analogconsultants.com/