mn-msta.com
General Category => General Banter => Topic started by: VFJayR on April 03, 2013, 09:45:26 PM
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So, Monday I was going through my helmet cleaning ritual - liners, shields, condition etc. - and figured that I should really investigate replacing the removable liners in my favorite helmet. Once I got them out they looked a little.... Worn. Anyway while all the padding was out I cot a peek at the manufacture date - 08/06....
So that got me thinking. The 5 year thing was the rule back when helmets were made out of plastic, correct? With cheaper non removable foam liners, also correct?
So with a helmet that is made from a laminate with removable liners, does the rule apply? Is it more of a milage and exposure rule now?
Regular rules of helmet care are apply - not dropped, not resting on gas tank, etc.
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The comfort padding -- the part that you can remove and wash -- doesn't do much to protect your brain in a crash.
The polystyrene impact-absorbing liner -- the part of the helmet that provides most of the impact protection for your brain -- is what degrades and makes the helmet less protective over time.
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Shoei Helmets have a lifespan of 5 years from purchase date and 7 years from manufacture date. Snell suggests you replace your helmet every 5 years.
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I remember reading an article in one of the moto magazines about five years ago either written by, or referencing, James Ouellet who was one of the authors of the original Hurt report and is now the president of Motorcycle Accident Analysis Inc. He said that the five year life of a helmet is not necessarily true. He said that if the shell is intact (hasn't been dropped and has no visible cracks) and the chin strap is still properly attached and not weakened, the helmet still has plenty of life left in it. He ran some DOT impact certification tests on some 10+ year old helmets and they passed tests to the standards they were built to with no problem.
Sorry but I can't produce the actual article.
I still replace my helmets about every five years anyhow as the chin strap is usually pretty frayed and even if I haven't dropped the helmet it's still been banged around enough that I figure that I need to get a new one.
Dale B
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He ran some DOT impact certification tests on some 10+ year old helmets and they passed tests to the standards they were built to with no problem.
Interesting. It seems obvious that a helmet isn't going to go from being 100% in Year 5 to 0% in Year 6, The degradation is likely to be gradual and progressive. I'd also expect a helmet that's been worn 50 hours might protect better than one that's been worn 10,000 hours.
Dale, do you remember whether these were helmets that had been in use for 10+ years, or helmets that had spent their lives inside a box in a climate-controlled environment?
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The liner may also crush a bit from wearing and making for a looser fit which isn't good protection wise. GJ ???
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The polystyrene may shrink a bit but I've never seen old Styrofoam significantly degrade unless left in the direct sun day in and day out. I understand Brent's POV, just not sold that it degrades significantly in 10 years if care is taken to not expose the helmet to persistent heat or sunlight.
I think helmet fitment is a better rationale to change it out. Or when the fashion starts looking dorky.
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The polystyrene may shrink a bit but I've never seen old Styrofoam significantly degrade unless left in the direct sun day in and day out. I understand Brent's POV, just not sold that it degrades significantly in 10 years if care is taken to not expose the helmet to persistent heat or sunlight.
I've never measured the degradation of polystyrene in any objective way, so I can only guess, but if it shrinks, then it has become more dense and therefore less protective. (Unless some of its mass has evaporated or something. I really don't know why it would shrink other than from being pressed between the shell and the rider's head.)
I think helmet fitment is a better rationale to change it out. Or when the fashion starts looking dorky.
Or when the Snell standard changes. M2010 was a significant change from M2005. Otherwise, I think Dale's rationale of a frayed chin strap is as as good as any.
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When you wear the helmet it is in the sun and heat....perspiring in there too....so sure a rider who rarely rides/wears one vs a rider who rides/wears it everyday, well there is bound to be a significant difference.
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I remember reading an article in one of the moto magazines about five years ago either written by, or referencing, James Ouellet who was one of the authors of the original Hurt report and is now the president of Motorcycle Accident Analysis Inc. He said that the five year life of a helmet is not necessarily true. He said that if the shell is intact (hasn't been dropped and has no visible cracks) and the chin strap is still properly attached and not weakened, the helmet still has plenty of life left in it. He ran some DOT impact certification tests on some 10+ year old helmets and they passed tests to the standards they were built to with no problem.
Sorry but I can't produce the actual article.
I still replace my helmets about every five years anyhow as the chin strap is usually pretty frayed and even if I haven't dropped the helmet it's still been banged around enough that I figure that I need to get a new one.
Dale B
The polystyrene may shrink a bit but I've never seen old Styrofoam significantly degrade unless left in the direct sun day in and day out. I understand Brent's POV, just not sold that it degrades significantly in 10 years if care is taken to not expose the helmet to persistent heat or sunlight.
I've never measured the degradation of polystyrene in any objective way, so I can only guess, but if it shrinks, then it has become more dense and therefore less protective. (Unless some of its mass has evaporated or something. I really don't know why it would shrink other than from being pressed between the shell and the rider's head.)
I think helmet fitment is a better rationale to change it out. Or when the fashion starts looking dorky.
Or when the Snell standard changes. M2010 was a significant change from M2005. Otherwise, I think Dale's rationale of a frayed chin strap is as as good as any.
Right - This is the line of thought that I was vaguely remembering: That the important bits of the helmet - Shell - EPS liner - Strap - are the ones that "age" a helmet. and as long as they check out then the helmet is safe. EX: Arai's 5 year guarantee/Warranty starts from the date of sale.
So in that vein,
-- modern helmets with removable liners provide a cleanable barrier between the head/sweat and the EPS foam attached to the shell.
-- Gasoline fumes significantly degrade (shrink) the EPS liner.
-- Impacts and UV rays degrade the shell
-- (which leads to a question: Does modern Laminate construction fare better for UV exposure than plastic?)
These would indicate that modern helmets, under normal conditions, should keep their protective properties for longer than 5 years.
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From the Snell company:
"The five-year replacement recommendation is based on a consensus by both helmet manufacturers and the Snell Foundation. Glues, resins and other materials used in helmet production can affect liner materials. Hair oils, body fluids and cosmetics, as well as normal "wear and tear" all contribute to helmet degradation. Petroleum based products present in cleaners, paints, fuels and other commonly encountered materials may also degrade materials used in many helmets possibly degrading performance. Additionally, experience indicates there will be a noticeable improvement in the protective characteristic of helmets over a five-year period due to advances in materials, designs, production methods and the standards. Thus, the recommendation for five-year helmet replacement is a judgment call stemming from a prudent safety philosophy."
Obviously the more you ride the more you are subjecting your helmet to wear and tear so if you're only out occasionally your helmet might still be safe to use after 5 years but if you've dropped it on the ground a few times then maybe not so much. I have read articles where every 3 years was suggested but considered to be "too soon" by other readers who state the helmet manufacturers suggest you replace them sooner just to make more money. IMO I think 5 years is a good starting place and then take into consideration your personal use. Another thing to consider is new technology. Do you want the latest and greatest? Here's another article I read about some new helemt technology called 6D ODS, and btw they suggest replacement every 3 years.
http://www.motocross.com/features/6d-helmets-suspension-for-your-head/ (http://www.motocross.com/features/6d-helmets-suspension-for-your-head/)
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I bought an ebay unit to replace the liners in my 9 year old helmet now. It's more comfortable and a bit quieter now with the plush newer stuff.
I think the 5 year limit is lawyer talk based on the percentage of helmets/users that have been probably been abused or dropped and should be replaced. Car seats are labeled the same way. If they're stored inside I have a tough time you have to replace it just because it's 5 years old, it's a solid piece of plastic. If it's wore out or brittle replace it.