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Helmets - mean time betweef failures - Page 3

post #31 of 118

Re: Helmets - mean time betweef failures

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 crap 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
post #32 of 118

Re: Helmets - mean time betweef failures

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.
post #33 of 118

Re: Helmets - mean time betweef failures

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?
post #34 of 118

Re: Helmets - mean time betweef failures

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
post #35 of 118

Re: Helmets - mean time betweef failures

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.
post #36 of 118

Re: Helmets - mean time betweef failures

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
post #37 of 118

Re: Helmets - mean time betweef failures

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
post #38 of 118

Re: Helmets - mean time betweef failures

On Tue, 03 Jan 2006 08:20:41 GMT, "Andrew Price"
<arathorn@bigpone.net.au.x1> 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
post #39 of 118

Re: Helmets - mean time betweef failures

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 --
post #40 of 118

Re: Helmets - mean time betweef failures

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 | dave@hired-goons.net
"I've found that nurturing one's Zen nature is vital to dealing with
technology. Violence is pretty damn useful too" - Lionel Lauer
post #41 of 118

Re: Helmets - mean time betweef failures

Rayc wrote:

> 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


According to Zebee's post on motorcycle helmets, all the old ones passed the
tests. No, you don't have any assurances except that a number of units
tested passed the test criteria. This may or may not have any relevance to
real life situations. a lot of data collected over the last 20 years say
that helmet wearing has little or no effect on fatality rates of bicyclists.

> 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.


You think helmet manufacturers are the best people to judge expected life? I
think this is more likely a "What the market will bear" judgement.

> 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.


As I said, I'm still wearing my old Bell. OTOH my motorcycle helmet is only
about 6 or 7 years old. :-)

> You can never know when your going to have an accident, so hoping for
> best odds, I would want to have the best protection.


Best to stay in bed then.

Theo
post #42 of 118

Re: Helmets - mean time betweef failures

Bleve wrote:
> Theo Bekkers wrote:


>>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


Geez, I didn't know Unix made computers. Where do I get a Unix processor and
motherboard?

Theo
post #43 of 118

Re: Helmets - mean time betweef failures

TimC wrote:

> And dear ghod, I'm glad weren't not using apple clones now.


It was Apple's insistance on keeping their hardware propriety that allowed
IBM clones and Microsoft to outsell and undersell them and eventually the
Microsoftware caught up to the Apple operating system. How little time ago
was it when we were restricted to 8 character file names on MS systems ?

Theo
post #44 of 118

Re: Helmets - mean time betweef failures

Rayc wrote:
> 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.


The point is that we don"t know. Zebee's post suggests that there is little
if any. A 12 yo helmet still passed the test.

>> 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.


But that foam works much better when the impact is distributed over a much
wider area by a hard shell. .

Theo
post #45 of 118

Re: Helmets - mean time betweef failures

The testing involves a penetration test as previously mentioned. A solid steel helmet would pass this test but would still hurt like hell if your head was in it.

Of course an old fibreglass motocycle helmet would pass this test (only has to do it once). I am not sure if they then measure the depth of indentation to determine the slowing effect of the material and as a result the force absorption.

The thing that amazes me is that given the option to headbut a road/car/tree with or without a helmet 99.9% of people are going to choose a helmet. So why would someone then decide that they wouldn't wear a helmet when undertaking an activity where the chances of this are elevated above activities such as walking? (the it will never happen to me syndrome because I am invincible and dont make mistakes........what a load of crap)

As far as justifying it with statistics, many people who wear a helmet do so in order to minimise injury in the event of an accident and not necessarily to avoid death. I imagine if an event severe enough to cause death whilst cycling (eg. being run over by a car) occured there would be internal injuries that caused most of the problems.

Also as far as people thinking they look like a dork well I guess they have some serious self confidence issues. (20 year old cycling helmet whist being retro is perhaps crossing the line because they were all awful )

What is so wrong with a product having a service life? Everything else on a pushbike does. People are very happy to spend big dollars getting the latest frame/bike/parts but are then willing to skimp on a helmet.

It would suck to have motor function problems that make getting your own dinner a problem (or worse) because you were to cheap/cool to actually protect your head.
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