helmet duration of life

[kawashima]

I have Arai tour cross which I bought in 2002, and still using it.
I haven't dropped it yet and it looks clean for its age.
I'm curious how big difference there is between new one regarding safety when I crash.
Is it better to buy a new helmet by some years?

https://i21.photobucket.com/albums/b295/kawashima_/P1050564_zps92a542cf.jpg
https://i21.photobucket.com/albums/b295/kawashima_/P1050565_zpsb606e78a.jpg

A few feeks ago, I brought some cash and visited mega bike parts shop and tested Arai RX-7, Rapide-IR, and ASTRO-IQ, but I felt them very tight, I felt uncomfortable when I try to put on my glasses, I prefer relaxed tour cross.
And I confirmed that if I need a new one, I will buy tour cross again. Came home and looked at my helmet, wondered if I should still use this.
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own:2020 Serow 250
owned: 2012 YB125SP, 2008 TDM900, 2005 W650, 2002 LS125R, 2002 CB400SF, NS50F, C50 / Trip to UK(2009), Hokkaido touring(2013)

[MarJay]

Fibreglass lids have a life of 5 years. You should have replaced it by now really I think.
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[Dalemac]

There should be an expiry stamp on the strap somewhere, which should tell you how long the helmet has left to live.

If you can't find one/it is rubbed off, it is definitely too old to use.

Most helmets have a life of around 5 years after production - that hemlet should have been replaced in 2007, 2012, and you should be half way through another helmet by now

Mine is due for replacement quite soon.

Do as you wish though, it's your head.
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YBR125 -> GPZ500S -> SL1000

[Mumrah]

I heard that even lids that haven't been used but that come in contact with daylight for prolonged periods will also deteriorate.

Probably better to keep your noggin safe and invest in a new one

[P.addy]

I still have a lid from 2009, so 5 years, it is coming to the end of its usable life

I'd probably not risk longer than that.

[pinkyfloyd]

I was taught the shelf lives are as follows.

Plastic around 3 years.
Fibreglass around 5 years
carbon/carbon kevelar around 7 years.
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[shereen]

Defo time for a new lid. Also when you try on a new lid they should be fairly tight, you face will mould into the padding eventually which will make it fit better.
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[Yaka]

dont understand why take the risk, buy a new one.

when i got my helmet i was surprised how damn tight fit it was, but the dealer was insistant it was the right fit. now its worn in its more comfy and and my glasses are easier to put on and off
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Current Bike : 2008 Varadero XL125
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[Joncrete Cungle]

I got my current lid in 2006ish, not dropped it or derped in it so I am happy to carry on wearing it.

[djrikki]

[Dave70]

I'd certainly be after gettin a new lid once it gets to five years old.

You've definitely had more than your moneys worth out of that one, time to replace it, I would think.

Also, as other stated. A new lid should feel a little too tight when new. I wasn't aware of this until I was on my third and current one. It is now a perfect fit and very comfortable. Whereas, my other two soon became too loose, even though they seemed okay when new.

[kawashima]

[Teflon-Mike]

Motorsport authorities have stipulated the 'guideline' three or five year helmet life into the 'stone' of thier regs.
Legally, the Freddie-Spencer Replica 'Ariai-Super Vent' dating back to 1984, sat on a relatives shelf, wearing its original ACU Gold and BSI approval triangle is still legal to wear on the road.
Practically?
Helmet shell, is either polycarbonate, or phenolic 'Glass-fibre' composite. Shells function is mainly to hold the impact absorbing expanded polystyrene foam that cusions your head from impact together for as long as there's impact. Polystyrene, does the job of saving head, absorbing energy through plastic deformation as its crushed.
Life?
Polycarbonate; same stuff as plastic washing up bowls are made off, and envomentalists hate, as its not biodegradeable, and has an inordinately long half life, measured in decades.
DOES however degrade, but depends on enviromental factors.
Stuff hates the presence of Chloride ions and UV light.
Leave a plastic washing up bowl outside full of bleach, and it will go hard and crack in a couple of years.
GRP? If you have ever used a Davids GRP glass-repair kit; you make the stuff by mixing resin with an activator, which makes the long polymer chains 'cross-link' and go hard. Use too little, stuff never sets; use to much and it boils. Get it right and you get a plastic that's pretty tough, if a little brittle, and, theoretically lasts forever.. people still pay silly money for 'Bakalite' collectables from the 1920's & 30's that's essentially the same stuff. Does have a tendancy for embrittlement over time; though. As lattice in composite, though, its only half the story, bedded around a dissimilar material, usually glass, vibration expansion and contraction, will tend to see the composite start to craze or de-laminate, and in old classic cars of the 50's & 60's and in boats, GRP structures are given lifes anything from 10 years to perhaps 30, depending on how stressed they are.
For a crash-hat? provided its not bashed or stuck in salt water, or bleach? Could last 100 years or more.

So, shells ought to last pretty well, certainly an awful lot more than the 3 or 5 year guideline suggested by manufacturers and interested bodies. Maybe ten, twenty years, or so and still retain enough integrity that 'safety' is not significantly impared.

Remember; shells job is just to hold the polystyrene round your head. Hit it hard enough, its gonna break; small difference in how much force is needed to reach that threshold between brand new material, and ten year old material, pretty small.

So, stuff that saves your bonce... maybe... the polystyrene.

Polystyrene, not much different to the poly-carb of the shell. Doesn't much like UV light, nor chloride ions, or organic solvents... well.. actually it DOES like solvents... thats how they make it.

Expanded polystyrene is made by taking hard polystyrene beads, soaking them in solvent, and letting the solvent 'swell' the plastic, making the polymer strands expand, and go wooly.... then evaporating off the solvent, to leave the soft foamy beads you get in kids bean bags. To make a bit of packing for a sterio or the lining of a crash-helmet, those beads are then shot into a mould, whilst still slightly solvent damp, to get them to stick together, then the remaining solvent evaporatied by reduced pressure, to give you block of styrafoam.

Now, this is going to degrade naturally a lot faster than the shell. Almost impossible to 100% remove the solvent used to expand the polystyrene in the first instant, and actually you probably don't want to. The small amount of remaining solvent, helps keep the plastic soft; polystyrene, in raw state is rather brittle, stuff they make airfix models out of, and you know how that will 'crack'.

So, the performance of the impact cusion, depends on the polystyrene staying reasonably soft so it will deform in an impact.

And this will tend to be the life Governing bit of the 'system'.

In use, the foam will be compressed and de-compressed by putting the helmet on and off, as well as movement and vibration whilst in use.

New helmets 'bed in' as the foam slowly relaxes and comforms to your head shape, loosing some of its crushability, but only tiny amount.

Over time, that process, though will continue; but again, significance ought to be pretty minimal to how much less impact energy the stuff might absorb.

More significant will be age hardening of the polystyrene as those plastisising solvents dry out, and the foam starts to go powdery.

Without other influences, that will tend to take about ten to twenty years; but, even then, cusion can still retain an awful lot of its original impact absorbing capacity, just through being there and still being crusheable.

Process will tend to be accelerated, however, by enviromental stress, and inside the hat, in close proximity to your scalp through pourouse lining material; often chloride rich har-cair products left in your hair, natural sweat etc can help accelerate degradation.

How MUCH really is a bit of string question, and ultimately pretty accademic, its performance will reduce, but in the scheme of things, the significance of that natural degredation in terms of safety is unlikely to be so big that the hat is ever 'unsafe'.. just a question of how less safe, and at that point we are arguing Sharpe Ratings... and talking abot cheap hats that fit verses expensive hats that dont, and better hats that have harder life.

So, cutting through loads of techno-babble debunking sales-hype and safety-fear...

I go by 'wear and tear'. When lining is a bit raggy, good indication that the rest of the hat has seen enough use to be past its best and time to get a new one.

On a cheap hat, hard used, every day, that could be inside a year.
On expensive hat, used seldom... could be a decade.

Authorities 'suggest' 3-5 years....

Apply your own common bludy sense.

Safety comes from using your head, not sticking it in a plastic bucket and thinking you got it covered.... less from expecting the plastic to keep you safe... worse worrying how safe the plastic might or might not be!

Use the grey matter inside.. THAT is only damn thing that can keep you safe, and better things to apply that grey stuff to than how long polymers may or may not last... like dodging that ruddy SMIDSY!
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[kawashima]

Today I bought Shoei GT-Air. I'm very happy thanks!
https://i21.photobucket.com/albums/b295/kawashima_/P1050569_zpsb66737a2.jpg
____________________
own:2020 Serow 250
owned: 2012 YB125SP, 2008 TDM900, 2005 W650, 2002 LS125R, 2002 CB400SF, NS50F, C50 / Trip to UK(2009), Hokkaido touring(2013)

[Kickstart]