cracked helmet shell dangerous?



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Ned Mantei

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The "microshell" on my helmet has cracked in several places after falling to the ground many times,
but the helmet has never been subject to a hard knock as in an accident. Is integrity of the shell
important for the function of the helmet in an accident? I could imagine that the shell would keep
the inner part of the helmet from falling into pieces after an initial impact, but am not clear as
to whether that matters, assuming that the initial impact would be the only impact. Is there any
data on this, or at least well-founded opinion?

--
Ned Mantei Department of Cell Biology, Swiss Federal Institute of Technology CH-8093 Zurich,
Switzerland
 
I would trash it. And go buy a new one to your liking.

I MTB 2004
 
By your .sig you're uniquely qualified to evaluate the 'helmet' question yourself. As a co-worker of
mine posted on his cubicle, "Ask your own questions. Find your own answers." He escaped being pinned
into the overhead by an expelled center control rod by the 'sniffles'.

"Ned Mantei" <[email protected]> wrote in message news:mantei-FF484C.10203917022004@pfaff2-rz-
fast.ethz.ch...
| The "microshell" on my helmet has cracked in several places after falling to the ground many
| times, but the helmet has never been subject to a hard knock as in an accident. Is integrity of
| the shell important for the function of the helmet in an accident? I could imagine that the shell
| would keep the inner part of the helmet from falling into pieces after an initial impact, but am
| not clear as to whether that matters, assuming that the initial impact would be the only impact.
| Is there any data on this, or at least well-founded opinion?
|
| --
| Ned Mantei Department of Cell Biology, Swiss Federal Institute of Technology CH-8093 Zurich,
| Switzerland
 
This is a multi-part message in MIME format.

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hmmm Huff-man? just curios have you seen Love Liza? "Doug Huffman" <[email protected]> wrote
in message = news:[email protected]... By your .sig you're uniquely qualified to
evaluate the 'helmet' = question yourself. As a co-worker of mine posted on his cubicle, "Ask your
own questions. Find your own answers." He escaped being pinned into the overhead by an expelled
center control rod by the 'sniffles'.

"Ned Mantei" <[email protected]> wrote in message news:mantei-FF484C.10203917022004@pfaff2-rz-
fast.ethz.ch...
| The "microshell" on my helmet has cracked in several places after falling to the ground many
| times, but the helmet has never been =
subject
| to a hard knock as in an accident. Is integrity of the shell =
important
| for the function of the helmet in an accident? I could imagine that =
the
| shell would keep the inner part of the helmet from falling into =
pieces
| after an initial impact, but am not clear as to whether that =
matters,
| assuming that the initial impact would be the only impact. Is there any data on this, or at
| least well-founded opinion?
|
| --=20 Ned Mantei Department of Cell Biology, Swiss Federal Institute of Technology CH-8093
| Zurich, Switzerland

------=_NextPart_000_0017_01C3F52D.03233BC0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-
Encoding: quoted-printable

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=3DContent-
Type content=3D"text/html; = charset=3Diso-8859-1"> <META content=3D"MSHTML 6.00.2800.1400"
name=3DGENERATOR> <STYLE></STYLE> </HEAD> <BODY bgColor=3D#ffffff>
<DIV><FONT face=3DArial size=3D2>hmmm Huff-man? just curios have you = seen Love=20
Liza?</FONT></DIV> <BLOCKQUOTE=20 style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT:
5px; = BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<>"Doug Huffman" <<A=20
=
href=3D"mailto:[email protected]">[email protected]</A>>= wrote=20 in message <A=20
=
href=3D"news:[email protected]">news:ReednfKxF7ZHk6_dRVn= -
[email protected]</A>...</DIV>By=20 your .sig you're uniquely qualified to evaluate the
'helmet'=20 question<BR>yourself. As a co-worker of mine posted on his = cubicle,
"Ask=20 your own<BR>questions. Find your own answers." He escaped = being=20
pinned into the<BR>overhead by an expelled center control rod by the=20
'sniffles'.<BR><BR><BR>"Ned Mantei" <<A=20
=
href=3D"mailto:[email protected]">[email protected]</A>>= wrote=20 in
message<BR><A=20
=
href=3D"news:[email protected]">news:ma= ntei-FF484C.10203917022004@pfaff2-rz-
fast.ethz.ch</A>...<BR>|=20 The "microshell" on my helmet has cracked in several places after<BR>| =
falling=20 to the ground many times, but the helmet has never been subject<BR>| = to a hard=20 knock
as in an accident. Is integrity of the shell important<BR>| for = the=20 function of the helmet in
an accident? I could imagine that the<BR>| = shell=20 would keep the inner part of the helmet from
falling into pieces<BR>| = after an=20 initial impact, but am not clear as to whether that
matters,<BR>| = assuming=20 that the initial impact would be the only impact.<BR>| Is there any =
data on=20 this, or at least well-founded opinion?<BR>|<BR>| -- <BR>| Ned = Mantei<BR>|=20
Department of Cell Biology, Swiss Federal Institute of Technology<BR>| = CH-8093=20 Zurich,
Switzerland<BR><BR></BLOCKQUOTE></BODY></HTML>

------=_NextPart_000_0017_01C3F52D.03233BC0--
 
Ned Mantei <[email protected]> wrote in message news:<[email protected]>...
> The "microshell" on my helmet has cracked in several places after falling to the ground many
> times, but the helmet has never been subject to a hard knock as in an accident. Is integrity of
> the shell important for the function of the helmet in an accident? I could imagine that the shell
> would keep the inner part of the helmet from falling into pieces after an initial impact, but am
> not clear as to whether that matters, assuming that the initial impact would be the only impact.
> Is there any data on this, or at least well-founded opinion?

Hi, why take a chance. There are lots of very nice helmets in all price ranges. In fact Giro has
dropped the price of the Eclipse fromm $99.95 to $79,95. But there are often deals on last years
models. Or check out Ebay. I suggest that you buy the best helmet that you can comfortably afford.
The better ones are more comfortable, fit better, and are lighter in weight. Hopefully the anti-
helmet brigade won't feel the need to start the debate*. You obviously have made the decision to
wear a helmet, so the only issue should be the integrity of the helmet in question. Replace it!

*A helmet is no substitute for safe riding habits. In my opinion, it does no harm and is helpful.
Whether or not it will make a real difference in a major crash, I believe that it will help prevent
minor injuries, such as bumps and scrapes. Both of which I would rather avoid.

Life is Good! Jeff
 
Never use a helmet that has cracks in them! Already after one fall it is completely useless.

Erik
 
In article <[email protected]>,
[email protected] (Jeff Starr) wrote:

>*A helmet is no substitute for safe riding habits. In my opinion, it does no harm and is helpful.
>Whether or not it will make a real difference in a major crash, I believe that it will help prevent
>minor injuries, such as bumps and scrapes. Both of which I would rather avoid.

A helmet can do much more! I once fell while crossing wet streetcar tracks (admittedly that would be
an unlikely sort of accident in the U.S.A.). I fell hard to the side, breaking my collarbone. To
this day, 15 years later, I can remember how the helmet took up the shock as my head came whipping
around and the side of my head crashed into the ground. I am convinced that without the helmet I
would either have been dead or survived with significant brain damage. Good old V-1 Pro.

P.S. To clarify my original post: The shell on my newer helmet cracked after falling to the ground
because I repeatedly dropped it, not because I kept falling from my bike. The helmet thus
hasn't really seen much in the way of shock or impact.

--
Ned Mantei Department of Cell Biology, Swiss Federal Institute of Technology CH-8093 Zurich,
Switzerland
 
Ned Mantei wrote:

> The "microshell" on my helmet has cracked in several places after falling to the ground many
> times, but the helmet has never been subject to a hard knock as in an accident. Is integrity of
> the shell important for the function of the helmet in an accident? I could imagine that the shell
> would keep the inner part of the helmet from falling into pieces after an initial impact, but am
> not clear as to whether that matters, assuming that the initial impact would be the only impact.
> Is there any data on this, or at least well-founded opinion?
>

You will probably get many responses based on the concept of a helmet as a magic talisman. Those who
view helmets that way, feel that any desecration of the sacred object will reduce its ability to
thwart the dark forces of the universe.

And you've already gotten some responses saying "Why think about it? It's only $80." (And we wonder
why so much of the population lives in debt!)

As to tests, physics, etc.: You're unlikely to find any data on crash tests of a helmet old enough
to have little cracks. Testing costs money, and no helmet company will pay to tell you that you
_don't_ need a new helmet. (In that way, a lack of data indicates you're fine.)

But you may recall that in the early '80s, helmets were certified and sold with no shell at all. The
likelihood of helmet failure by explosion on impact must have been judged fairly low. Our ever-more-
cautious* society now worries about it, of course, but there are lots of similar worries that seem
silly to me.

My view? The likelihood of even a brand new bike helmet doing anything significant to protect you is
very low, as shown by data that's been discussed here endlessly. So how likely is it that your
helmet will a) do something significant to protect you, then b) shatter because of some small cracks
in a 0.003" plastic cover, then c) separate to uncover your head, then d) allow your head to strike
a second time with enough force to cause serious damage?

I think the odds are down around the level of having a cigarette lighter stop a bullet aimed at your
heart. IOW, if you always carry a Zippo lighter for protection, then replace your helmet
immediately. Otherwise, go ride your bike.

*ever-more-cautious except, of course, when actively promoting "extreme" sports, for which "you must
ALWAYS wear your helmet!!!!"

--
Frank Krygowski [To reply, omit what's between "at" and "cc"]
 
On Tue, 17 Feb 2004 10:20:39 +0100, Ned Mantei
<[email protected]> wrote:

>The "microshell" on my helmet has cracked in several places after falling to the ground many times,
>but the helmet has never been subject to a hard knock as in an accident. Is integrity of the shell
>important for the function of the helmet in an accident? I could imagine that the shell would keep
>the inner part of the helmet from falling into pieces after an initial impact, but am not clear as
>to whether that matters, assuming that the initial impact would be the only impact. Is there any
>data on this, or at least well-founded opinion?

My understanding was that the plastic shell is to help hold the foam together in the case of impact.
Considering that yours is cracking on drops which I assume do not exceed the force of a crash impact
(if for no other reason than that there is not the weight of the head in the helmet), I wonder what
this plastic shell really does, though. Maybe just to keep the foam from getting dinged and gouged
and compressed by the user- no real role in an crash?

A helmet manufacturer will tell you to replace it, of course. Have you asked the manufacturer? Can
they provide data to support the need for an uncracked shell?
 
Dan Daniel <[email protected]> writes:
> My understanding was that the plastic shell is to help hold the foam together in the case
> of impact.

The other benefit of the shell is that it doesn't stick to pavement as easily. If you fall and
slide, the foam might grab onto the pavement and give you whiplash. Slippery plastic is less likely
to do this. (No, I have no data to back this up, just intuition. Sorry.)

Chris
--
Chris Colohan Email: [email protected] PGP: finger [email protected] Web: www.colohan.com Phone:
(412)268-4751
 
Frank Krygowski wrote: (snip)
> And you've already gotten some responses saying "Why think about it? It's only $80." (And we
> wonder why so much of the population lives in debt!)

Oh yes, the population is in debt because we spend too much money on helmets.

By the way, how much money did the PC you're posting from cost? I assume that it is your first one,
and that it's probably an IBM PS/2 mod 70, about 9 years old? Need to amortize the cost of it over
as many years as you can,right?

(snip)
> But you may recall that in the early '80s, helmets were certified and sold with no shell at all.

You mean like the Cinelli leather "hairnets"? Tell us you're basing your profound advice on
that, PLEASE!

.
>
> My view?
Yes, we're waiting for it after all of that really smart warmup you've given us.

>The likelihood of even a brand new bike helmet doing anything significant to protect you is very
>low, as shown by data that's been discussed here endlessly.
You're right. It's actually the water content of the skin that saves you when you hit pavement.
Since water is uncompressible no shock can get through to your skull. It's scientifically proven!

>So how likely is it that your helmet will a) do something significant to protect you, then b)
>shatter because of some small cracks in a 0.003" plastic cover, then c) separate to uncover your
>head, then d) allow your head to strike a second time with enough force to cause serious damage?
>
> I think the odds are down around the level of having a cigarette lighter stop a bullet aimed at
> your heart. IOW, if you always carry a Zippo lighter for protection, then replace your helmet
> immediately.
Of course if you've got that cigarette lighter and it's stopped bullets several times, don't you
think you might start to catch a glimpse of the fact that the lighter did in fact save you, more
than once, even when geniuses like you suggest that it's a waste of money and the cause of our
international trade deficit.

> Otherwise, go ride your bike.

I assume that your's is your first bike, and you've not spent money on more than one! If helmets are
a waste of money, surely a second bike is too.

You're a genius, you really are.

BB

>
>
>
> *ever-more-cautious except, of course, when actively promoting "extreme" sports, for which "you
> must ALWAYS wear your helmet!!!!"
 
On Tue, 17 Feb 2004 10:20:39 +0100, Ned Mantei
<[email protected]> may have said:

>The "microshell" on my helmet has cracked in several places after falling to the ground many times,
>but the helmet has never been subject to a hard knock as in an accident. Is integrity of the shell
>important for the function of the helmet in an accident? I could imagine that the shell would keep
>the inner part of the helmet from falling into pieces after an initial impact, but am not clear as
>to whether that matters, assuming that the initial impact would be the only impact. Is there any
>data on this, or at least well-founded opinion?

I am not an expert, but...

In my opinion, the shell's function is minimal in an impact. I would not worry about cracks. Your
experience may vary.

I am not aware of a specific location to obtain hard data which directly answers your question.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.
 
On 17 Feb 2004 06:41:56 -0800, [email protected] (Jeff Starr) may
have said:

>Hi, why take a chance. There are lots of very nice helmets in all price ranges. In fact Giro has
>dropped the price of the Eclipse fromm $99.95 to $79,95. But there are often deals on last years
>models. Or check out Ebay.

For those with large heads, life may sometimes be oddly better. None of the helmets at the local
bike shops and cycling boutiques were large enough for me, but the cheap large Bell from Academy fit
perfectly...and a few days later, a spare popped up for $5 at Goodwill, looking pristine and unused,
of the same brand and size, and nearly the same model, in a more acceptable color than the garish
ones at Academy.

I have problems believing that a $90 Giro will do any more than a $30 Bell when it's needed.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.
 
On Tue, 17 Feb 2004 11:42:23 -0500, Frank Krygowski
<[email protected]> may have said:

>But you may recall that in the early '80s, helmets were certified and sold with no shell at all.
>The likelihood of helmet failure by explosion on impact must have been judged fairly low. Our ever-more-
>cautious* society now worries about it, of course, but there are lots of similar worries that seem
>silly to me.

I've never had that put forth as the reason for the shell. It's really too thin and too dainty to
perform that function anyway, from what I can see. "Skids without grabbing" has been mentioned, but
my personal opinion is that the primary purpose of the shiny shell is to look pretty and get the
user to buy and wear the helmet. Naked foam is ugly.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.
 
Troll seed:
On Tue, 17 Feb 2004 10:20:39 +0100, Ned Mantei
<[email protected]> wrote:
>The "microshell" on my helmet has cracked in several places after falling to the ground many times,
>but the helmet has never been subject to a hard knock as in an accident. Is integrity of the shell
>important for the function of the helmet in an accident? I could imagine that the shell would keep
>the inner part of the helmet from falling into pieces after an initial impact, but am not clear as
>to whether that matters, assuming that the initial impact would be the only impact. Is there any
>data on this, or at least well-founded opinion?

Troll fertilizer: On Tue, 17 Feb 2004 06:11:36 -0500 (EST), [email protected] wrote:
> I would trash it. And go buy a new one to your liking.
>
>I MTB 2004

Troll water: On 17 Feb 2004 06:21:00 -0800, [email protected] (Aziraphale) wrote:
>Never use a helmet that has cracks in them! Already after one fall it is completely useless.
>
>Erik

...and the plant that's guaranteed to spring up as a result: On Tue, 17 Feb 2004 11:42:23 -0500,
Frank Krygowski <[email protected]> wrote:
>And you've already gotten some responses saying "Why think about it? It's only $80." (And we wonder
>why so much of the population lives in debt!)

And now me, stupidly joining the fun:

I doubt that most people, let alone the quote "much of the population", spend $80 on a helmet. More
commonly people with money to waste. Furthering your debt $80 for a helmet that can be equivalently
had for $30 is probably a sign that it's too late to bother protecting your brain.
--
Rick Onanian
 
RE/
>"Skids without grabbing" has been mentioned, but my personal opinion is that the primary purpose of
>the shiny shell is to look pretty and get the user to buy and wear the helmet. Naked foam is ugly.

Seems like for awhile, at least, somebody was selling naked foam and some people were buying lycra
pullovers for them.

--
PeteCresswell
 
Frank Krygowski <[email protected]> wrote:

> But you may recall that in the early '80s, helmets were certified and sold with no shell at all.
> The likelihood of helmet failure by explosion on impact must have been judged fairly low. Our ever-more-
> cautious* society now worries about it, of course, but there are lots of similar worries that seem
> silly to me.

Frank, that is probably a fallacious argument, although the amount of improvement in safety with the
shell is not known. Leaving aside the question of whether wearing a helmet is worthwhile, if helmets
A and B pass the certification test, and A has no shell while B does, that does not mean that B can
pass the test without a shell. There may be differences in the construction of A and B.

My recollection of shell-less helmets is that they had thicker foam than today's helmets. Today's
helmets also have many more vents, so may be more prone to break up on impact. That's just
speculation on my part. I recall that for the lightweight Giro helmets with a Lycra cover (no longer
made, but still relatively common) the cover was supposed to help keep the foam together on impact.

I think if you're going to bother wearing a helmet, it might as well be in good condition. I'd be
too cheap to throw a helmet away on appearance of the first 1/8" long crack in a microshell, but
many cracks would worry me.
 
Rick Onanian wrote:

> Troll seed:...
>
> Troll fertilizer:...
>
> Troll water:...
>
> ...and the plant that's guaranteed to spring up as a result:
...
>
>>And you've already gotten some responses saying "Why think about it? It's only $80." (And we
>>wonder why so much of the population lives in debt!)
>
>
> And now me, stupidly joining the fun:

Ever notice that as soon as your garden begins growing, weeds pop up? ;-)

> I doubt that most people, let alone the quote "much of the population", spend $80 on a helmet.

Guys, I didn't really mean that the entire national debt was due to spending money on
helmets. Please.

What I meant is that there are too many people whose solution to _any_ problem is "buy a new one."
Kind of like the apocryphal Texan who bought a new Cadillac whenever the ashtray got full.

I guess I violated a rule by alluding to larger issues in a helmet thread, eh?

--
Frank Krygowski [To reply, omit what's between "at" and "cc"]
 
Werehatrack wrote:

>
> I have problems believing that a $90 Giro will do any more than a $30 Bell when it's needed.

According to Consumer Reports tests, the more expensive helmet will probably do less! Their test
ratings consistently show less impact absorption for "better" helmets.

Which is perfectly logical, of course. More expensive helmets feature less weight and more
ventilation holes. The extra cost comes from trying to shave weight as much as possible while still
BARELY passing the certification tests.

Cheap helmets leave more material in place, so less design & testing is necessary. As a result, they
typically pass with a higher margin.

--
Frank Krygowski [To reply, omit what's between "at" and "cc"]
 
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