Life of a Helmet

[Trumpettom001]

This is in the same vein as honey - They've found honey still in moderately o.k. conditions 1000's of yearsafter it was used to mummify pharoes and what-not... but yet honey from tesco has a shelf life of 2 years!!!

 

[HJ]

There are suggestions that newer designs are far from "better" and older helmet designs are safer!

During the last couple of years, the technical staff at HPRL has encountered an interesting-and possibly dangerous-problem with the aerodynamic-shaped or streamlined bicycle helmets. These popular helmets have a teardrop design which tapers to a wedge at the rear of the helmet, supposedly reducing aerodynamic drag along with increased ventilation through the many openings in the shell.

The adverse effect of this aerodynamic shape is that the wedge at the back of the helmet tends to deflect and rotate the helmet on the head when impact occurs there. Any impact at the front or sides of the streamlined helmet is no different from other helmet shapes, but any impact on the rear wedge tends to rotate the helmet on the head, probably deflecting the helmet to expose the bare head to impact, and at worst ejecting the helmet completely from the head. Actually, everybody who has tested these streamlined helmets over the past years has encountered the problem of these helmets being displaced during impact testing at the rear wedge. Usually additional tape was required to maintain the helmet in place during rear impact tests; usually the basic retention system alone could not keep the helmet in place during impact testing on the rear of the helmet.

Unfortunately, the implication of helmet displacement and possible ejection in an actual accident impact did not register as a real hazard in previous years of testing, but now there are accident cases appearing that show this to be a genuine hazard for bicycle riders wearing these streamlined helmets. Accident impacts at the rear of these streamlined helmets can cause the helmet to rotate away and expose the head to injury, or eject the helmet completely. The forces generated from the wedge effect can stretch the chinstraps very easily, and even break the [occipital--Prof. Hurt used a trademarked name] retention devices.

We request that F08.53 committee study this problem and develop advisory information for both manufacturers of these streamlined helmets and consumer bicyclists who now own and wear such helmets. There is a definite hazard for displacement or ejection from impact on the rear wedge of these helmets, and bicyclists should be warned of this danger by an authority such as ASTM.

s/Hugh H. Hurt, Jr
Professor Emeritus-USC
President, Head Protection Research Laboratory

s/Christopher B. Swanson
Laboratory Manager, Head Protection Research Laboratory

One example (Evidence to the ASTM helmet standards committee)

Oh come on Cunobelin, you ken that helmets are about fashion and not safety

 

[ufkacbln]

Oh come on Cunobelin, you ken that helmets are about fashion and not safety

So are socks and sandals!

 

[Steve Austin]

This is in the same vein as honey - They've found honey still in moderately o.k. conditions 1000's of yearsafter it was used to mummify pharoes and what-not... but yet honey from tesco has a shelf life of 2 years!!!

Brilliant!

 

[Zoiders]

UV degredation of the plastic shell would be my worry along with cold damage to plastic clips and hardware, it goes brittle.

As long as it's not too bashed about and stored out of sunlight then I can see getting more than 5 years out of a lid.

 

[lukesdad]

My XC helmet (giro) is 10 years old loads of bashes scratches etc. Nothing wrong with it.

 

[ufkacbln]

My XC helmet (giro) is 10 years old loads of bashes scratches etc. Nothing wrong with it.

Which probably renders it totally useless..... but then again its a magic hat with omnipotent protection capabilities.

 

[Iainj837]

I thought it was 5 years before replacing,

 

[lukesdad]

Which probably renders it totally useless..... but then again its a magic hat with omnipotent protection capabilities.

Well the last bash was a few months ago pretty big one to over the bars, broke my nose but the helmet survived ok... So...What do you know!

 

[Blue]

Cycling Plus did a review of helmets a while back wherein they quoted one of the main manufacturers advising an 8 year life for an undamaged helmet.

 

[ufkacbln]

Well the last bash was a few months ago pretty big one to over the bars, broke my nose but the helmet survived ok... So...What do you know!

I "know" that you are using something that by all the written evidence and manafacturer's literature is likely to fail when you need it...... one would certainly question whether this is a wise decision, its a bit like chicken and recooking. All the advice is against it, but not everyone will get food poisoning.... but lots of people will

However if you do wish to ignore the evidence and wear a helmet that you know may be compromised then of course that is your choice entirely.


Incidentally your anecdotal evidence clearly shows why the British Dental Association and the Head Injury charity Headway now advocate full face helmets!

 

[lukesdad]

Can t argue with the full face helmet off road, I d have a few issues with one on the road though.

 

[HJ]

UV degredation of the plastic shell would be my worry along with cold damage to plastic clips and hardware, it goes brittle.

As long as it's not too bashed about and stored out of sunlight then I can see getting more than 5 years out of a lid.

You also have to make sure that you don't wear it while riding in sunlight either...

 

[ufkacbln]

You also have to make sure that you don't wear it while riding in sunlight either...

Do undead cyclists come under Special Interests?

 

[Zoiders]

You also have to make sure that you don't wear it while riding in sunlight either...

The time spent wearing it is not going to be anywhere near the time it sits about doing nowt is it?

You know, that 10 hours or so a day when you have to work, the other hours when you are sleeping, having a shoot, shaving, eating etc etc.

Unless of course you wear your helmet all the time like all the other boys and girls on the window lickers bus.