Helmets - mean time betweef failures



In aus.bicycle on Wed, 04 Jan 2006 17:06:40 +1100
Random Data <[email protected]> wrote:
> On Wed, 04 Jan 2006 01:30:03 +0000, Zebee Johnstone wrote:
>
>> Just to make life more difficult... The bod in charge of testing
>> motorcycle helmets for Oz compliance recently tested a bunch of old
>> helmets - some worn a lot, some not much, the oldest 12 years old.

>
> Moto helmets are very different from push bike helmets, and I suspect
> exceed the design requirements by a fair bit. Out of interest, was there a
> noticeable difference between new and old, or were the models sufficiently
> different that this wouldn't mean anything?
>


I don't know for sure, but he didn't say so. THe impression I got was
they all passed the tests, and it's not that easy to get a handle on
how much any helmet has left in it once it's passed.

Motorcycle helmets certainly are butcher than pushbike ones :) Also,
I suspect they resist UV better as the polystyrene is not exposed as
it often is on the smaller more open pushbike lids.

But the method of protection is the same - they both work by having
the polystyrene compressed so as to both cushion and spread the load.

That a 12yo helmet could pass the test makes me think this "must
replace in 3/5 years" idea is either marketing or **** covering.

Zebee
 
On 2006-01-04, Peter Keller <[email protected]> wrote:
> What? A bump causing a small bruise on your head caused that amount of
> massive damage to the helmet?
> My!! Aren't they protective!!


The question is: what would the damage to the head have been had the
helmet not been in place?

I'm not saying that they *are* protective -- just that it's something of
a non sequitur to say "bruise to the head + massive damage to the helmet
= helmet isn't protective." To make that call, you need two identical
impacts on two heads that differ only by the presence of the helmet,
followed by a comparison of the damage to the two heads.

Or in other words: I am neither defending nor attacking the use of
helmets. I am merely attacking the logical non-argument used by Peter.

My personal take: I am required by law to wear a helmet. Therefore, I
wear a helmet. Unless and until that law is repealed or changed, I see
no point in arguing the point further.

--
My Usenet From: address now expires after two weeks. If you email me, and
the mail bounces, try changing the bit before the "@" to "usenet".
 
A bike helmet must meet the Australian Standards no matter how old it is. This implies that the latest helmet shall meet the same minimum standard as the Rosebank Stackhat of 20 years ago. So for impact protection they both provide similar protection. (remember here that one is a soft shell and the other a hard shell). The main difference with a modern helmet is that it is a lot lighter and has better airflow. This also goes for the bottom to top of the range.

Looking at the foam padding of them, the polystyrene is pretty much the same in both and that is what does all the work. The shell merely stops the foam from being ground away as your head runs along the ground.

Provided the Polystyrene is in good condition (i have always checked polystyrene by seeing if it is going chalky) there should be no reason why i would stop using it apart from daggy looks. If it has been in an impact of any kind, i'd throw it away and spend my money on a new helmet as this one has done its job and will be compromised in case of a future accident.
 
Peter Keller wrote:
>
> On Wed, 04 Jan 2006 11:18:54 +1000, Tamyka Bell wrote:
>
> >> >
> >> I am not sure if an "inspection" service is useful at all. The propaganda
> >> is that after any knock, however minor, the helmet should be replaced as
> >> damage to it may be invisible but still real, thus lessening greatly
> >> whatever protective properties it had.
> >>
> >> Peter

> >
> > I found a miniature compression spot on a helmet after I'd stacked it...
> > which happened to correspond to a small bruise on my head, so I decided
> > to check it out. When we peeled back the plastic, we found a massive
> > crack that was not at all visible from outside. The bike shop was very
> > responsible and insisted I smash the **** out of the helmet so that no
> > one would take it out of the bin and try to use it. The thought of that
> > scared me - I am always amazed when people sell second hand bikes with a
> > helmet included.
> >
> > Tam

>
> What? A bump causing a small bruise on your head caused that amount of
> massive damage to the helmet?
> My!! Aren't they protective!!


I really hope that was sarcasm.

Ever seen the demonstration where someone lies on a bed of nails, with a
bessa block on their abdomen, and someone else smashes the brick with a
sledgehammer.

Speaking from experience - if the brick doesn't break, it bloody hurts.

Tam
 
It amazes me that people actually argue about the protection offered by a helmet.


From my experience a helmet does a hell of alot.

1. Had a minor accident (sitting on my bike out the front of my parents house and was knocked over by a friend stopping beside me) while not wearing a helmet. It resulted in my head hitting a gutter on the left hand side resulting in a fractured skull and a week in hospital for my troubles.
2. Broke a rear hub axel while out of the saddle leaving a friends driveway which resulted in the chain slipping and me going over the bars head first into the ground. Resulted in a dented and cracked helmet and a snapped collarbone. But I was able to get up and walk home.
3. Crashed face first in a DH race into rocks which resulted in a broken finger, dislocated knee and alot of skin loss. Cracked the fibreglass in the mouthpiece of my full face helmet. Was able to get back on my bike and roll to the finish line.
4. Crashed in a fast section of a DH race which resulted in a dent and cracking on the side of a full face helmet and a broken collar bone. Was able to walk to the bottom of the track.
5. Front wheel tapped a 6m double in a quad compressor mtb race at 40+ kph which resulted in me landing on my head from a long way up. Helmet was broken in 7 places and I also had a broken hand. Was able to walk up to the first aid tent for treatment. (Lotte drove me home).
6. I always wore a helmet in skateparks on my bike as a teenager which my mates loved to give me a hard time about. Had numerous crashes where my head hit the concrete and I was ok. My friends all ended up getting helmets after another friend crashed and split his head open and ended up in hospital for 2 weeks because he wasn't wearing a helmet.

These experiences have showed me that across all types of riding when a crash happens and a head hits the ground it is always better off in a helmet. Admittedly I have put myself into situations where the likelyhood of a crash is higher (that is why I wore a full face helmet in DH) but two of my worst crashes that inflicted the most damage both occured below 10kph in a road setting.

The incident that caused the fractured skull would have been quite funny to my friends if I hadn't have been unconcious and vomiting (so I am told) on the side of the road.
 
smartie wrote:
> A bike helmet must meet the Australian Standards no matter how old it
> is. This implies that the latest helmet shall meet the same minimum
> standard as the Rosebank Stackhat of 20 years ago.


I agree, except for the point that -that helmet used during that period
of twenty years, would surely have suffered some degredation, UV
exposure, falling on the ground when a bike falls over, body oil
contamination etc. So how or by what method can we test or be given
assurances that the 20yr old helmet can still absorb the same impact

>So for impact
> protection they both provide similar protection. (remember here that
> one is a soft shell and the other a hard shell). The main difference
> with a modern helmet is that it is a lot lighter and has better
> airflow. This also goes for the bottom to top of the range.
>
> Looking at the foam padding of them, the polystyrene is pretty much the
> same in both and that is what does all the work. The shell merely stops
> the foam from being ground away as your head runs along the ground.
>
> Provided the Polystyrene is in good condition (i have always checked
> polystyrene by seeing if it is going chalky) there should be no reason
> why i would stop using it apart from daggy looks.


That is my point, helmet manufacturers have given us a expected life of
the helmets ( up to 5yrs) they have supplied reasons (UV exposure,
contamination etc) and I believe that these are acceptable constraint
for a helmet's working life.
I would not want to keep using a helmet beyond these limits without
some method of accurately testing a helmet (other than destruction).

So my train of thought goes........
a helmet can only last so long....... max of 5yrs - less with uv
Exposure, contamination,etc................. I want maximum shock
absorbtion... so replace helmet every 2-3 years.
You can never know when your going to have an accident, so hoping for
best odds, I would want to have the best protection.
r
 
TimC wrote:
> On 2006-01-04, Theo Bekkers (aka Bruce)
> was almost, but not quite, entirely unlike tea:
>> Rayc wrote:
>>> If your Betamax recorder still works then who am I to argue.

>>
>> I was never stupid enough to buy one.

>
> Stupid? What was stupid about betamax?
 
TimC wrote:
> Theo Bekkers wrote
>> Rayc wrote:


>>> If your Betamax recorder still works then who am I to argue.


>> I was never stupid enough to buy one.


> Stupid? What was stupid about betamax?


Nothing stupid about the system. It actually is far superior to VHS. It was
Sony's attempt to keep the technology to themselves and make a huge profit
that was the problem. Much like Apple really. If Apple had licenced their
computer technology we'd all be using Apple clones now instead of IBM
clones.

Theo
 
Rayc wrote:

> Not an arguement, just an observation.


> if your happy to keep using something that is widely accepted as
> outdated and sub standard, then by all means.


Umm, it has the same standards sticker on it as this years helmet crop, so
how is it sub-standard?

> The idea that a 19yr old helmet, is still good to wear and will protect
> you is not something that I want to test on me or my loved ones.


Mine is a hard shell (as they all were then). I would think the current
"less shell" models would not give me better or equal protection.

> Newer helmets generally fit alot better. Thats where the money
> generally goes for the better helmets - R&D.


Mine fitted very well when I bought it (It was a very expensive helmet at
the time) and my head has not changed shape since.

Theo
Please try to include at least a little of who and what you're replying to
so that I, and others, can follow the conversation.
 
Random Data wrote:

> So did you? I dropped bricks on the last few helmets I had to get rid
> of - they were showing cracks and/or depressions after a few largish
> hits, so I thought it was time to get rid of them. A house brick,
> edge on, leaves a fair mark in a helmet from about 3m up.


That equates to hitting something solid at about 26 km/h. Hmmmm.

Theo
 
Random Data wrote:

> Moto helmets are very different from push bike helmets, and I suspect
> exceed the design requirements by a fair bit. Out of interest, was
> there a noticeable difference between new and old, or were the models
> sufficiently different that this wouldn't mean anything?


Motorcycle helmets have to pass a penetration test by having an object (your
brick?) dropped on it at 23 km/h. Hmmm again.

Theo
 
Theo Bekkers wrote:
> TimC wrote:
> > Theo Bekkers wrote
> >> Rayc wrote:

>
> >>> If your Betamax recorder still works then who am I to argue.

>
> >> I was never stupid enough to buy one.

>
> > Stupid? What was stupid about betamax?

>
> Nothing stupid about the system. It actually is far superior to VHS. It was
> Sony's attempt to keep the technology to themselves and make a huge profit
> that was the problem. Much like Apple really. If Apple had licenced their
> computer technology we'd all be using Apple clones now instead of IBM
> clones.


a lot of us *are* using UNIX :)
 
On 2006-01-05, Theo Bekkers (aka Bruce)
was almost, but not quite, entirely unlike tea:
> TimC wrote:
>> Theo Bekkers wrote
>>> Rayc wrote:

>
>>>> If your Betamax recorder still works then who am I to argue.

>
>>> I was never stupid enough to buy one.

>
>> Stupid? What was stupid about betamax?

>
> Nothing stupid about the system. It actually is far superior to VHS. It was
> Sony's attempt to keep the technology to themselves and make a huge profit


I wasn't aware of the history, only the bit about it being better than
VHS. Makes all the more sense now. Consumers aren't necessarily
stupid, afterall.

> that was the problem. Much like Apple really. If Apple had licenced their
> computer technology we'd all be using Apple clones now instead of IBM
> clones.


And dear ghod, I'm glad weren't not using apple clones now. Although,
I suspect, if I stay in astronomy, I'm going to end up having to help
all the mac newbies out on their mac systems because it is only half
arsed unix and keeps breaking in subtle ways. Dunno why macs are so
popular, when we have a perfectly good unix system. Probably the same
reason tcsh is still popular around here.

--
TimC
Modus Ponens in action:
- Nothing is better than world peace.
- A turkey sandwich is better than nothing.
==> Ergo, a turkey sandwich is better than world peace. --unknown
 
On Tue, 03 Jan 2006 08:20:41 GMT, "Andrew Price"
<[email protected]> wrote in aus.bicycle:

>Big chunk of styrofoam fell out of the Limar helmet on the way home from
>work tonight, right where the strap attaches at the back.
>
>5 years constant use, a few minor scrapes (there was that low tree branch
>once as I recall) so I guess I can't complain - but I really think it was
>the rash threat to wash it because it was getting a bit pongy in the heat
>that caused it to give up the ghost.


Umm. I have had three helmets in something like 20 years (yes I wore
one before it was required by law) and the only failure has been on
an early model where the foam strip stuck to the inside of the
polysyrene started to crumble into a powder. This was long after I
stopped using it. As far as I can see my current one, aTwister ($25),
is showing no deteriation and I think it is about 7 years old perhaps
a bit more.

Anyway when you think about it even if you did have to replace it
every five years $5 a year is less than what you spend on tyres in
that time.


Regards
Prickles

This message only uses recycled electrons
 
Bleve wrote:
> Theo Bekkers wrote:
>
>>TimC wrote:
>>
>>> Theo Bekkers wrote
>>>
>>>>Rayc wrote:

>>
>>>>>If your Betamax recorder still works then who am I to argue.

>>
>>>>I was never stupid enough to buy one.

>>
>>>Stupid? What was stupid about betamax?

>>
>>Nothing stupid about the system. It actually is far superior to VHS. It was
>>Sony's attempt to keep the technology to themselves and make a huge profit
>>that was the problem. Much like Apple really. If Apple had licenced their
>>computer technology we'd all be using Apple clones now instead of IBM
>>clones.

>
>
> a lot of us *are* using UNIX :)
>

Indeed
 
On Wed, 04 Jan 2006 07:48:36 +0000, Stuart Lamble wrote:


>
> I'm not saying that they *are* protective -- just that it's something of
> a non sequitur to say "bruise to the head + massive damage to the helmet
> = helmet isn't protective." To make that call, you need two identical
> impacts on two heads that differ only by the presence of the helmet,
> followed by a comparison of the damage to the two heads.
>
> Or in other words: I am neither defending nor attacking the use of
> helmets. I am merely attacking the logical non-argument used by Peter.
>
> My personal take: I am required by law to wear a helmet. Therefore, I
> wear a helmet. Unless and until that law is repealed or changed, I see
> no point in arguing the point further.


There are other alternatives, including emigrating to a country where one
is not required to wear a helmet. (at last count 193 of them).
However, uncontrolled personal experience is everything -- *sigh*
Many helmet "wars" may be at least partially defused if we realised that
those against mandatory helmet laws are not necessarily against the
wearing of helmets.

Peter


--
No Microsoft involved. Certified virus free --
 
On Thu, 05 Jan 2006 12:39:11 +0800, Theo Bekkers wrote:

> That equates to hitting something solid at about 26 km/h. Hmmmm.


Edge on - I wouldn't want to catch the corner of a stopped truck at
26km/h. The helmet was still recognisable, but there was a *big* crack in
it. Remember this helmet had already had a few big hits, and there was
noticeable denting of the foam.

Then again I've got a lovely bruise on my hip from a virtually stopped
front wheel slide (off the side of a rock, which I then landed on) to say
that speed isn't everything.

--
Dave Hughes | [email protected]
"I've found that nurturing one's Zen nature is vital to dealing with
technology. Violence is pretty damn useful too" - Lionel Lauer
 
Theo Bekkers wrote:

> Umm, it has the same standards sticker on it as this years helmet crop, so
> how is it sub-standard?
>

I'm sure that the helmet was standards compliant when manufactured, but
what about now?
The general wear and tear of general use and the exposure to UV and
contaminates surely affect the shock absorbation ability of that
helmet.

Thats the point of this thread, asking the acceptable working life of a
helmet. Having a helmet that can absorb as much impact as possible, is
what I would like to have , and am quite happy to ensure that I have
this on my bonce.


> > The idea that a 19yr old helmet, is still good to wear and will protect
> > you is not something that I want to test on me or my loved ones.

>
> Mine is a hard shell (as they all were then). I would think the current
> "less shell" models would not give me better or equal protection.


Now arguement there, the hard shell helmet would offer more abrasion
resistance, but its the foam inside that absorbs the impact shock. This
abillty of the said 19yr old foam still absorbing the shock to the same
extent and ability is the arguement.
>
> > Newer helmets generally fit alot better. Thats where the money
> > generally goes for the better helmets - R&D.

>
> Mine fitted very well when I bought it (It was a very expensive helmet at
> the time) and my head has not changed shape since.
>
> Theo
> Please try to include at least a little of who and what you're replying to
> so that I, and others, can follow the conversation.

Sorry i thought I waas (mostly)
 
Rayc wrote -

> Thats the point of this thread, asking the acceptable working life of a
> helmet. Having a helmet that can absorb as much impact as possible, is
> what I would like to have , and am quite happy to ensure that I have
> this on my bonce.
>

As the OP of this thread I report having gone and bought a new Limar because
their shape still fits my head really well (ymm vary) and the lbs guy and I
did a bit of an autopsy on the dead one (slow day in t' shop). Things
observed -

1. Strap attachment to helmet is better - attachment no longer relies on
adhesion of a pad to soft polystyrene, which is where the original failed.
2. Suspension of head from helmet is better - yes there are more and larger
ventilation holes but there is also a slight gap where the soft mesh liner
keeps the polystyrene seperated from your head - improves ventilation and
comfort more than just the old stick in pads the old one had.
3. When we pulled the old one apart the polystyrene really had deteriorated
badly, especially where the straps were attached to it - crumbled with not
much applied force in the weakest bits - was clearly past its use by date.
Probably worth giving the helmet a bit of an inspection every so often,
rather than assuming continued integrity as a given.
4. New ones do seem to offer a bit more protection behind the ear and come
down lower in that region.
5. Liked the quick adjustment wheel at the back - I tend to wear a head band
to warm the ears in winter and its going to be easier to adjust the helmet
for that.
6. Looks dorkier than the old one, but then again you aren't going to see
cool models on the catwalk featuring helmets anytime soon, unless the OH&S
people really get out of control.
7. Limar offer a 3 year replacement for half original price if you do have a
gravity assisted rapid dismount and use the item for its intended purpose (I
think other manufactrurers may do something similar) - seemed a fair deal.
8. Less expensive Giro lookalikes (called Tec I think) are starting to
appear for about 1/3 the price if the top of the line jobs and seemed to
weigh much the same - no info on longevity of the knock offs yet available -
had the relevant AS approved sticker attached to them for what that's worth.

Have no wish to ever enter the never ending h*lm*t effectiveness debate -
its just if you have to by law have one, its good to know they seem to be
trying to improve them.

But I suspect the effective lifespan of the current ones, with constant use,
is relatively short.

best, Andrew
 
Andrew Price wrote:

> As the OP of this thread I report having gone and bought a new Limar ......

and the lbs guy and I did a bit of an autopsy on the dead one ....
>
> 3. When we pulled the old one apart the polystyrene really had deteriorated
> badly, especially where the straps were attached to it - crumbled with not
> much applied force in the weakest bits - was clearly past its use by date.
> Probably worth giving the helmet a bit of an inspection every so often,
> rather than assuming continued integrity as a given.


Good to see you had a good look over the old one and was more than
happy with your decision to get a new one based upon close inspection
(albeit with destruction of said helmet)

> 7. Limar offer a 3 year replacement for half original price if you do have a
> gravity assisted rapid dismount and use the item for its intended purpose (I
> think other manufactrurers may do something similar) - seemed a fair deal.


they're not all that bad really, there's a cost involved but not the
full whack ($ rrp)

> 8. Less expensive Giro lookalikes (called Tec I think) are starting to
> appear for about 1/3 the price if the top of the line jobs and seemed to
> weigh much the same - no info on longevity of the knock offs yet available -
> had the relevant AS approved sticker attached to them for what that's worth.


Trickle down !
>


>
> But I suspect the effective lifespan of the current ones, with constant use,
> is relatively short.


best of luck with keeping this one for a while!