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General Category => General Discussion => Topic started by: boatdetective on October 02, 2015, 10:50:01 PM
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So, I'm interested to hear technically why there is an arbitrary recommendation to replace helmets every five years. I don't want to hear "because the manufacturers say so", or "because in that span it most likely rolled off the table once or twice". I want some justification that shows that the expanded foam liner somehow degrades. I just don't buy it.
Personally, I'll probably want a new lid purely out of vanity. However, I don't see where there is a hard engineering reason to toss the old one.
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I view it as a CYA specification, and will replace my helmet when I believe it has degraded enough to increase my risk of injury. I realize this invites opposing view posts, and that's OK. :grin:
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Read somewhere it has to do with degradation of the shell .
Dusty
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It's probably because if you don't wear a headskin to keep your body oils out of the soft foam, that foam will disentigrate. Or the same logic to convince you to never keep a tire longer than 5 years no matter how it's treated. :grin: Whatever you decide to do, you have been warned. That way the manufacturers are not liable.
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From what I remember it's the natural fatigue of the material. Fiberglass as it was explained to me, shrinks over time and looses it's elasticity. I don't know about modern composite or plastic helmets. This is what I remember from 30years ago. I find that after 5or 6 years, my helmets don't fit as well as they once did. Looser and more comfortable but, I do know that a loose helmet does not protect your head as well.
http://www.bing.com/search?q=why%20do%20we%20need%20to%20replace%20motorcycle%20helmets&qs=n&form=QBRE&pq=why%20do%20we%20need%20to%20replace%20motorcycle%20helmets&sc=0-0&sp=-1&sk=&cvid=A9C6CFCAE6D3427A974DBC7B6330F305
I'm working from my stupid tablet so cut and paste doesn't work that well. But, here's some information
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a good excuse to sell more helmets?
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I feel better, now that I'm not alone. :laugh: I would be very surprised if decent glass/epoxy or glass/polyester or molded polycarbonate shell degraded significantly after five years, especially considering the outer layer of pigment that probably blocks most/all UV. Maybe there's something to be said for the sweat attacking foam theory, but I've used bicycle helmets with polystyrene foam for many years with no degradation that I can feel. The expiration date is almost certainly like the one my wife noticed this evening... ... on dental floss!
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i probably wear mine too long. I like to buy helmets when there's a close out sale. Last years model is ok with me.
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I work daily with fiberglass and the resin most certainly does not embrittle with time. Older GP polyester resin technically would "shrink" due to cross linking over time. However, this would not change the properties. The "body oils" attacking foam makes no sense to me either. More and more, I think this is a figure determined by defense attorneys rather than scientists.
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The plastic shell will definitely degrade over time due to exposure to sunlight. Newer helmets ma resist this a little better than older Ones. Grease oil solvents also effect plastic. If manufacturers say 5 years, your not in the saddle all day everyday and keep your helmet in a dark cupboard it would be reasonable to keep a helmet considerably longer.
One curious fact about biodegradation of plastics is that the color effects life so if I get this the right way around, a red helmet should in theory outlast a yellow one.
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I recall that one of the motorcycle magazines (could it have been Motorcycle Consumer News) did an article a few years back where they took some of their old (in some cases VERY old) helmets and subjected them to impact testing, to simulate the tests run on new helmets. Their conclusion was that unless the helmet was subjected to impacts (like falling off the bike or being routinely stored atop a sissy bar) or subjected to chemical attack (probably for the polycarbonate helmets), they really didn't degrade significantly.
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I'd suspect a larger part of the 5 years, which is from use, and 7 years from date of manufacture no matter what, has to due with liability.
I'd wager dollars to donuts that a OEM will walk away from any claim and cite the timeframe as the reason. This would have to be backed up by some kind of "evidence" that the time frame is valid.
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Polycarbonate *is* attacked by hydrocarbons. How much and over what time period needed to degrade a helmet is open to conjecture. Fiberglass and carbon fiber are attacked by heat/sunlight. There is a reason that plastic airplanes are *required* to be white because of this. Friends don't let friends fly plastic airplanes.. especially if they've been tied down outside for any length of time.
:popcorn:
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Isn't the concern about the impact absorbing liner, that it hardens either due to exposure and/or use? If it becomes packed down/more dense it transmits more force in a crash.
I wouldn't compare bicycle helmets because possible impact forces should be dramatically lower.
That said, I kept my last, rarely worn FF Arai something like 15 years.
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Millions of big trucks with fiberglass tilt hood/fenders pounding the highway and all the Corvettes haven't vaporized :grin: Older Vettes usually developed a lot of cracks after maybe 10 years...But vehicles are subject to a lot more vibration and shock while in use than a helmet...
As mentioned, how the helmet is stored will affect it's life....
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Consider the amount of use a helmet gets over five years.
Some are worn for several hours everyday in all weathers, others are worn for a couple of hours at the weekend during summer months, so the 5 year thing is completely arbitrary IMO.
AFAIK the biggest deteriorator is UV light so those exposed to the most must surely deteriorate quicker? as such I'm happy to leave mine longer because I fall more into the sunny weekend user than everyday commuter. Other than for damage I generally replace mine when the interior starts wearing out...
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Replace your Corvette every five years. That goes for boat hulls, too.
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Replace your Corvette every five years. That goes for boat hulls, too.
Apples and Oranges..
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Replace your Corvette every five years. That goes for boat hulls, too.
Man, GM and the Marine Industry would give you a big sloppy French kiss if there was any truth behind that.
In practice, the resins used in a laminate are not exposed to UV, as the finish is generally painted or gelcoated. Epoxy resin will get attacked by UV. UV will have an effect on (I believe) thermoformed plastics. However, I'm not so sure about cross linked, thermoset plastics. There are 45-50 year old fiberglass boats out there, and the last thing that is gone is the hull.
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Isn't the concern about the impact absorbing liner, that it hardens either due to exposure and/or use? If it becomes packed down/more dense it transmits more force in a crash.
I wouldn't compare bicycle helmets because possible impact forces should be dramatically lower.
That said, I kept my last, rarely worn FF Arai something like 15 years.
As I thought. You guys keep talking about the shell, but it sounds like it's the liner:
http://www.smf.org/helmetfaq#aWhyReplace
But they also admit it's a loose standard/judgement call:
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.
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For the same reason ballistic vest manufacturers put a 5 years expiration on their product. To sell more. Due to perceived liability they get replaced. I've shot vests that were 20+ years old and it still worked.
Expiration date on life protecting gear = $$$
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Strictly $$$$$$$$$ driven. As long as the liner & padding have not deteriorated, there's no reason to trash a helmet; especially at the prices that are presently being charged for quality helmets.
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I agree that it is not the shell. Even if UV would degrade the basic shell material, it has a protective coating, gelcoat or similar, that would take the brunt of the UV.
I also agree that the issue is the foam liner. Not the comfort foam, but, the beaded foam. That stuff does degrade over time, but, does it degrade enough to affect the performance? I think not, but, it depends on use and storage. How hot does it get in storage. How many oily products you use on your hair, how often it is cleaned and what it is cleaned with, etc, etc.
I can see why the mfgs have chosen a time limit, based on the most horrid of circumstances.
Having said all that I still replace my helmets after 5-7yrs. Mainly cause I want a new one, not becasue I fear for my safety :)
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Apples and Oranges..
NOT apples and oranges. People aresaying fiberglass deteriorates over time. If tha was true, my statement would be correct.
And GM and boat makers would be ecstatic.
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Took this directly from the UK Arai site as my RX-7 Corsair is now 8 years old and I wanted to know when I should start looking for a replacement.
Arai helmets are handmade to the highest possible standard, and although after many years the outside shell can look as good as new, it�s the EPS polystyrene liner that loses its ability to absorb impact over time. Arai recommend replacing your helmet 7 years after date of manufacture and 5 years after date of purchase to maintain the maximum levels of protection.The EPS liner is effectively the shock absorber of your helmet, absorbing the force of an impact onto the shell. This is done by the cells in the poly styrene being expanded (EPS = Expanded Polystyrene) and filled with air to absorb impacts. Over time, even when not in use, these liners lose their air pockets incrementally, after 7 years, dropping the shock absorbing ability of the liner below Arai�s safety standards. This is why we declare the helmet due for replacement so it can properly protect you against impacts.
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NOT apples and oranges. People aresaying fiberglass deteriorates over time. If tha was true, my statement would be correct.
And GM and boat makers would be ecstatic.
If you helmet was as over designed as a boat hull, it would be too heavy to wear. <shrug>
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This summer I took a sledgehammer to my 18 year old helmet. I would not worry about shell degradation. Frankly I doubt much was wrong with the liner, which eventually came out.
My boat is fiberglass and 41 years old. Not worried.
Bicycle and ski helmets are pretty much all liner. But oddly according to at least one study neither makes a significant difference in the prevention of serious head injury..
So I use the Smell 2015 test. If it smells bad this year I replace it.
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Although I replace my helmet every few years, it's obviously better to wear an old one than none at all.
As in, I don't think any obituaries read "He was wearing a helmet, but it failed due to sunlight degradation of the plastic, and this is the sole reason for his death."
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Here's my take.
Recommendations like these (and there are hundreds of them from helmet replacement to kids car seat replacement, or keeping kids turned rear facing till they are THREE etc., maybe even ballistic vests too) are all probably based on good SCIENCE.
They are probably determined for worst case scenario to MAKE SURE to absolutely minimize risk to life and limb.
Most of us who stretch these recommendations probably have some anecdotal story why we found it conservative, unnecessary etc. But our limited anecdotes obviously don't address the worst case scenarios.
What we can't really quantify is the important question of how much the risk changes. Does the risk of death or injury in any one given scenario change 1% or 10% or 50% if we ignore them?
Hell, they are already safety devices which are designed to be in place JUST in case but are pretty rarely used by any one of us in the first place.
So that's the question you have to ask yourself. How likely am I to need it and how likely am I to suffer from the potential degradation of the materials.
We can't do anything but take a guess and hope we didn't miss something in our risk assessment.
It's the same thing when we discuss oil types and change intervals.
So do what makes you feel warm and fuzzy.
I'd rather have a 15 Arai then no helmet at all. But then again, my new Arai I finally bought last year is clean and comfy. I'm glad I finally broke down and got a new one. Same goes for my new Shark 3/4.
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I wouldn't compare bicycle helmets because possible impact forces should be dramatically lower.
Some reasons that might not be a good generalization:
1. Bicycle helmets have a lot of ventilation spaces, so the pressure (psi) on the materials for a given impact is higher than for motorcycle helmets.
2. While average riding speeds are lower for bicycles, downhill speeds can easily get over 40 mph.
3. With some accidents, the speed that the 2-wheeled vehicle is going may not matter as much as the speed the car that hit it was going.
4. Many motorcycle helmet impacts result from the rider's head hitting the pavement, when it's able to slide, rather than be stopped by something like a curb, so the impact in those cases is mainly a fall from six feet up.
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One reason, and there are several is that the helmet spends a great deal if time in the sun and the UV attacks the outer shell. We have all seen what a lotnof exposure to the sun can do to many materials, even those that are claimed to be UV resistant. Very few man made materials are UV proof so after time they degrade.
Plastics, composites and such all degrade with time. The time limits helmet makers put on their wares is aligned with predicted rates of degradation so that you know when a helmet could be considered less than optimum at protecting your noggen.
Some people will choose to decide for themselves when a helmet isn't really suited to perform as they have better testing procedures, know more and the tin foil liners theybuse are so much better than what the engineers know and use.
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One reason, and there are several is that the helmet spends a great deal if time in the sun and the UV attacks the outer shell. We have all seen what a lotnof exposure to the sun can do to many materials, even those that are claimed to be UV resistant. Very few man made materials are UV proof so after time they degrade.
Plastics, composites and such all degrade with time. The time limits helmet makers put on their wares is aligned with predicted rates of degradation so that you know when a helmet could be considered less than optimum at protecting your noggen.
Some people will choose to decide for themselves when a helmet isn't really suited to perform as they have better testing procedures, know more and the tin foil liners theybuse are so much better than what the engineers know and use.
This is a blanket statement and just isn't based on demonstrable evidence. Once again, I know I come off as a jerk when I say it, but my job is assessing failure of composites on boats. The theory that all fiberglass composites gradually degrade just does not hold water.
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Isn't the concern about the impact absorbing liner, ...
^^^^^ This.
The issue is that the helmet can appear new, but the liner not only hardens but shrinks over time.
This creates a situation where your head (whether you value it or not) will encounter 2 impacts in an accident.
Just like for a helmet that's too large, the first is when the shell hits the object, the second is when your head hits a liner. And in this case, the liner is harder and less absorbent than it was when the helmet was new.
Has nothing to do with UV or how you've used or not used the helmet. Simply out-gassing of volatiles that keep the materials flexible.
That's why, in particular, clubs with track days won't let you use a helmet that's over 5 years old. Can you continue to use it on your own....of course. That the deceptive part is, the helmet probably feels more comfortable than it did when you bought it.
Your choice.
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That's why, in particular, clubs with track days won't let you use a helmet that's over 5 years old.
Of course it could also be the legal liability thing again.
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Of course it could also be the legal liability thing again.
Absolutely, it is the legal liability if they knowingly let you use helmets for their track days that can increase your chance of injury. And of course, it's NOT the guys who don't have an accident. It's the family of the deceased or the paraplegic that are looking for compensation.
I belong to the local Porsche Club. We haggled over this quite a while. On one hand, we didn't want to force people to go out to get a new helmet when their Snell approved helmet may only have been used a few times over the past years.
On the other hand, we had an obligation to our members to create safe track days and keep our insurance premiums for those events affordable.
The evidence was pretty clear.
But....note that suddenly at 5 years, the helmet will not become dangerous.
What they're saying is that a helmet can be expected to perform like new for at least 5 years. After that time, protection starts to deteriorate. But, clearly it's a gradual thing--faster for some brands and construction materials than others, faster for some usage than others, etc.
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Fiberglass is forever. Polycarbonate may not be. But the weak link is the EPS liner. When I moved last year, cleaning out the garage uncovered three ancient helmets -- my Bell 500 and Star and an old Shoei -- all 20 to 30 years old. As soon as I lifted, them, the liners turned to a chunky black powder that ran out onto the floor.
That's not going to happen in five years, of course, but the process begins sometime around the decade mark.
Helmets aren't the only time-limited safety equipment. The ski industry has a five-year limit on ski bindings -- beyond that, manufacturers won't indemnify retailers targeted by personal injury suits. Insurers don't want the long liability tail. So no shop will test or service bindings that aren't on the five-year indemnification list.
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Your head shrinks 1% a year. After 5 years your helmet is too loose. At age 100 all you have is ears and a nose.
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"I wouldn't compare bicycle helmets because possible impact forces should be dramatically lower."
Drop testing helmets simulates the vertical impact forces from a fall. I'm sure a 20 pound head form does not relate well to an entire 200 pound pile driver. Those tests do not measure hitting the wall at 100 whatever.
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Something to factor in , most of us old guys are so hard headed that a THIRTY year old helmet would probably suffice :shocked:
Dusty
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Fiberglass is forever. Polycarbonate may not be. But the weak link is the EPS liner. When I moved last year, cleaning out the garage uncovered three ancient helmets -- my Bell 500 and Star and an old Shoei -- all 20 to 30 years old. As soon as I lifted, them, the liners turned to a chunky black powder that ran out onto the floor.
That's not going to happen in five years, of course, but the process begins sometime around the decade mark.
Helmets aren't the only time-limited safety equipment. The ski industry has a five-year limit on ski bindings -- beyond that, manufacturers won't indemnify retailers targeted by personal injury suits. Insurers don't want the long liability tail. So no shop will test or service bindings that aren't on the five-year indemnification list.
Makes sense to me. My first Shoei, new in ...1985 ? was just fine through circa 2005, then the lining magically shredded itself, and came out in little fragments.
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If you helmet was as over designed as a boat hull, it would be too heavy to wear. <shrug>
But it's still fiberglass and it aint the fiberglass that deteriorates.
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As I see it the 5 year life span on helmets is due to two reasons, to sell more helmets and because by then the old one stinks.
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As I see it the 5 year life span on helmets is due to two reasons, to sell more helmets and because by then the old one stinks.
True--after 5 yrs my helmets are pretty funky. And I bathe regularly, often wear a do-rag or something between it and my head, esp on longer rides, etc.
Rich
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This is a blanket statement and just isn't based on demonstrable evidence. Once again, I know I come off as a jerk when I say it, but my job is assessing failure of composites on boats. The theory that all fiberglass composites gradually degrade just does not hold water.
All materials degrade over time. That banket statement is beyond question.
You're just relaying your experience and knowledge which is fine. The length of time it takes materials tondegrade varies but they all do without exception. Some may take a long time to degrade but motorcycle helmets are made of a variety of materials, nylon web straps, soft touch plastics and so on. They all degrade.
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For the last 25+ years, I have always worn a cotton or silk cover that covers all of my hair and the portion of my forehead that touches the helmet padding. Then, I wash those covers after every 3-4 rides so they can't get funky. My present helmet (Aria) has been used for around four years and looks brand new on the inside/has no smell, etc. due to always wearing the head cover. Good helmets are not cheap and doing this will extend the life of the padding from sweat and hair oil, etc.
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For the last 25+ years, I have always worn a cotton or silk cover...
These seem well made and stand up to regular washing. Not the cheapest.
http://www.gibson-barnes.com/dept-293830/Skull-Caps.html (http://www.gibson-barnes.com/dept-293830/Skull-Caps.html)
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Makes sense to me. My first Shoei, new in ...1985 ? was just fine through circa 2005, then the lining magically shredded itself, and came out in little fragments.
Proof the 5 year advisement doesn't sell more helmets.
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Older helmets tend to rattle more, for some reason ....
(http://i1299.photobucket.com/albums/ag77/Penderic/Penderic047/brain-shrink-674x450_zps8xvhhatf.jpg)
:grin:
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Pitch them after you have an accident.
Maybe the assumption is that on average, a motorcyclist has a crash every 5 years?
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Pitch them after you have an accident.
Maybe the assumption is that on average, a motorcyclist has a crash every 5 years?
I keep them for the memories........... ... :boozing:
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1) fiberglass (as well as many other things) never stops curing. It only slows down.
2) in 5 years, or less, I usually find that the lining and styrofoam now longer allow a good fit on my head.
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I keep them for the memories........... ... :boozing:
Funny... I still have a '70s Electro helmet with scrapes on the top of it from when I did a front flip with my H2 and slid in the gravel on my head.
There have been several posts about fiberglass that refer to it as if it's impervious, or it doesn't stop curing, or it does or doesn't degrade in sunlight. In reality fiberglass is... glass. It can be made into a laminate with epoxy, polyester, or many other binding agents. Its longevity is very dependent on that agent, since glass itself isn't likely to degrade in our lifetimes. Unless you specify the finished laminate, like G10 or FR4, for example, the term "fiberglass" in itself is relatively meaningless.
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Took this directly from the UK Arai site as my RX-7 Corsair is now 8 years old and I wanted to know when I should start looking for a replacement.
Arai helmets are handmade to the highest possible standard, and although after many years the outside shell can look as good as new, it�s the EPS polystyrene liner that loses its ability to absorb impact over time. Arai recommend replacing your helmet 7 years after date of manufacture and 5 years after date of purchase to maintain the maximum levels of protection.The EPS liner is effectively the shock absorber of your helmet, absorbing the force of an impact onto the shell. This is done by the cells in the poly styrene being expanded (EPS = Expanded Polystyrene) and filled with air to absorb impacts. Over time, even when not in use, these liners lose their air pockets incrementally, after 7 years, dropping the shock absorbing ability of the liner below Arai�s safety standards. This is why we declare the helmet due for replacement so it can properly protect you against impacts.
This is what I suspected was the part that is the issue.
So, why can't I buy a $20 replacement liner for my helmet and keep the shell?
If Schuberth would do that I'd go buy one in a heartbeat, or any other very expensive helmet out there.
Seems a shame to throw away a perfectly good helmet just because some cheap 'packing foam' degrades over time.
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The above statement is correct. styrofoam drys out over time and loses it shock absorbent properties. Left long enough it will crumble. I have seen this firsthand with an old helmet from my twenties that I kept around for sentimental reasons.
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For some reason a helmet always fits looser after a visit to a psychiatrist.
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This is what I suspected was the part that is the issue.
So, why can't I buy a $20 replacement liner for my helmet and keep the shell?
If Schuberth would do that I'd go buy one in a heartbeat, or any other very expensive helmet out there.
Seems a shame to throw away a perfectly good helmet just because some cheap 'packing foam' degrades over time.
Some brand helmets will sell you a new inside foam replacement, but I don't know for how long.
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So, out of curiosity, I looked up the degradation of expanded polystyrene (styrofoam). The sources stated that polystyrene is chemically inert and so resistant to acids and bases ( so much for the body oil argument. It also went on to mention the environmental problem with its resistant to natural breakdown. That seems to have the ring of truth also. If polystyrene just fades away, then there wouldn't be such a hue and cry about our overloaded landfills.
So far, science is lining up with the "this is BS " side of the fence.
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Your reasoning sounds good boatdetective. Polystyrene will degrade with exposure to UV, but it's really not many hours, percentage-wise, that the completely covered styrofoam layer of a helmet sees UV.
If, in my judgement, my helmet feels about like it did when it was new, and pieces of foam aren't getting in my eyes, for example, I'll keep using it. Others should do whatever they feel is appropriate for their own safety.
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I'm still using my white 1976 Shoie full face helmet. The liner is still in good shape, as is the styrofoam, with no sign of decomposition or degradation. The outer shell is intact, with no chips, cracks, or visible signs of degradation. When not being worn, the helmet is kept out of the light and heat. It seems to fit me well. I get a lot of razzing from people, but I'm okay with that, and the perception of higher risk. It also bothers them that I still wear jeans and not full armoured drawers. I am also a real daredevil and sometimes ride with no gloves! (gasp)
I recently had to find a new visor for my Shoei and that was a bit of a hunt.
JD
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Some reasons that might not be a good generalization:
1. Bicycle helmets have a lot of ventilation spaces, so the pressure (psi) on the materials for a given impact is higher than for motorcycle helmets.
2. While average riding speeds are lower for bicycles, downhill speeds can easily get over 40 mph.
3. With some accidents, the speed that the 2-wheeled vehicle is going may not matter as much as the speed the car that hit it was going.
4. Many motorcycle helmet impacts result from the rider's head hitting the pavement, when it's able to slide, rather than be stopped by something like a curb, so the impact in those cases is mainly a fall from six feet up.
I just made myself dizzy trying to read and understand the differences between DOT and Snell bicycle helmet and motorcycle helmet testing standards. I won't pretend I really got a full picture, but I'll say that there are whole sets of different standards, as we all know the final products are visibly dramatically different.
I stand by the gist of my comment that they probably shouldn't be compared when judging things like life span because they so different.
And though you make some good points that there is potential crossover in the possible range of forces they may encounter, I think you can easily agree there is much more potential for much higher forces in average motorcycle helmet use than bicycle.
Which is probably why there are such different designs, as well as standards for testing.
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So, out of curiosity, I looked up the degradation of expanded polystyrene (styrofoam). The sources stated that polystyrene is chemically inert and so resistant to acids and bases ( so much for the body oil argument. It also went on to mention the environmental problem with its resistant to natural breakdown. That seems to have the ring of truth also. If polystyrene just fades away, then there wouldn't be such a hue and cry about our overloaded landfills.
So far, science is lining up with the "this is BS " side of the fence.
I don't think what I'm reading from Snell or the helmet manufacturers suggest the lining disintegrates, I'm reading that it HARDENS.
The impact protection is provided by the give in the material. The gradual deformation under load to absorb the impact. If it hardens either through natural aging/atmospheric exposure it would still occupy landfills as well as your old helmet, but in the latter case it might not deform as well, transmitting higher forces to the wearer's head.
And I'm thinking I once read that part of the hardening occurs just from using it. That is, that the very act of wearing it (and it breaking into your head shape a bit) starts to compress the impact absorbing liner.
This also would account for why a helmet tends to loosen up over time.
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My guess is that the thin layer of soft foam rubber of the liner is the majority of what compresses over time and makes the helmet feel looser. It's definitely what disintegrated in my 30 year old Electro helmet, causing rubber powder to get in the wearer's eyes.
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My guess is that the thin layer of soft foam rubber of the liner is the majority of what compresses over time and makes the helmet feel looser. It's definitely what disintegrated in my 30 year old Electro helmet, causing rubber powder to get in the wearer's eyes.
That's the part that your body oils, sweat degrade and if you wear something between that and your actual hair/skin like I and others do it will last a lot longer. :boozing:
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OK, just to add to the confusion (but in the interest of full disclosure). Here is source (bicycle in origin) that is citing 2 studies (one supposedly Snell testing old motorcycle helmets, and another bicycle helmet test) that tested aged (on the shelf) helmets and saw NO DEGREDATION OF THE ENERGY ABSORING LINERS.
So this seems to be in direct contradiction to what I've been posting from other sources (ironically including SNELL). But it seems to support what Boatdetective has been saying from a materials standpoint.
:undecided: :huh: :undecided:
http://www.bhsi.org/replace.htm
Occasionally somebody spreads rumors that sweat and ultraviolet (UV) exposure will cause your helmet to degrade. Sweat will not do that. The standards do not permit manufacturers to make a helmet that degrades from sweat, and the EPS, EPP or EPU foam is remarkably unaffected by salt water. Your helmet will get a terminal case of grunge before it dies of sweat. Sunlight can affect the strength of the shell material, though. Since helmets spend a lot of time in the sun, manufacturers usually put UV inhibitors in the plastic for their shells that control UV degradation. If your helmet is fading or showing small cracks around the vents, the UV inhibitors may be failing, so you probably should replace it. Chances are it has seen an awful lot of sun to have that happen. Otherwise, try another brand next time and let us know what brand faded on you.
At least one shop told a customer that the EPS in his three year old helmet was now "dried out." Other sales people refer to "outgassing" and say that the foam loses gas and impact performance is affected. Still others claim that helmets lose a percentage of their effectiveness each year, with the percentage growing with age. All of that is nothing but marketing hype to sell a replacement helmet before you need it. There is some loss of aromatics in the first hours and days after molding, and helmet designers take account of that for standards testing. But after that the foam stabilizes and does not change for many years, unless the EPS is placed in an oven for some period of time and baked. The interior of your car, for example, will not do that, based on helmets we have seen and at least one lab crash test of a helmet always kept in a car in Virginia over many summers. Helmet shells can be affected by car heat, but not the foam. The Snell Memorial Foundation has tested motorcycle helmets held in storage for more than 20 years and found that they still meet the original standard.
Test Lab proof that performance holds up
In 2015 MEA Forensic reported on their extensive testing of used (but not crashed) bicycle helmets shows that the foam liners retain their performance over many years. Some of the helmets were as old as 26 years. They crash tested 675 helmets in their lab. Their analysis showed that there was no significant impact performance change with age. Their data including all 675 helmets tested produced only a 0.7g per year increase in impact readings at the higher drop height. After crash testing the helmets on a standard test rig, MEA took core samples from an uncrashed area of 63 helmets and tested them. This generated data based solely on the foam performance. Again, the findings indicate that helmet liner foam does not deteriorate with age. We have more on this landmark study in this Update newsletter.
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Thanks Kev. It's always nice to read that testing confirms my gut feelings. :grin:
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Thanks Kev. It's always nice to read that testing confirms my gut feelings. :grin:
:laugh:
Hey, just trying to find the facts, whether they agree with what I previously thought or not. lol. :thumb:
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Almost as good as an oil thread!
Having had my share of testing helmet structures over many years of mx racing, including splitting one from impact, my opinion is that a properly fitted new helmet is a wonderful thing compared to a sweated out, liner compressed old faithful. Plus, helmet technology is evolving, and i can say that shots i took later in my career and walked away from i do not think i would have back in the day. I want the best noggin cushion i can afford, having compressed the hell out of more than my fair share and lived to say "glad i had a good helmet on", without traumatic brain injury.
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without traumatic brain injury
Whenever I say something similar, my daughter asks "Dad, are you sure?"
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<<I'm still using my white 1976 Shoie full face helmet. >>
Notwithstanding the question of materials degradation, Got to figure there have been some improvements in helmet design in 39 years....
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Maybe and maybe not as far as safety goes.
Shell is still fiberglass (unless you have a plastic helmet).
Safety foam is still EPS.
Chin strap, yes.
Visors have improved a little bit as well as the size of the viewport.
I would bet if I still had my old Bell Star it would probably still pass the snell test that it was originally certified with.
But....I love the modular designs, internal sun visors, better venting and better comfort cushions which is why I have a newer helmet.
It isn't really a question of if I want a new helmet, it is, MUST I get a new helmet to be safe? I think the answer is no.
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Charlie, honest question as I don't know the answers, but I'd THINK even if the basic materials of the shell and liner are the same, don't you think they may have improved the fabrication techniques?
I'm under the impression helmets have gotten lighter and quieter. I guess I've assumed they've also gotten safer?
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I think sometimes we get a little precious about helmets.
I will replace a helmet if I feel I need to because the old one is either a/ damaged, or b/ gotten all lose and sloppy.
I do not believe that an empty helmet falling off a table or a bike will harm it in any significant way. It is after all designed to protect you from concussion level impacts. (with you in it)
All helmets offer some protection regardless of condition or type. None of them offer anything like the level of protection we would like to think they would. (they also increase the likelihood of walloping your head on the ground in the first place)
A 'use by date' there for is an artifice and is irrelevant. You are going to want to replace your helmet in any case long before it's effectiveness, such as it is, is seriously compromised.
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<<I'm still using my white 1976 Shoie full face helmet. >>
Notwithstanding the question of materials degradation, Got to figure there have been some improvements in helmet design in 39 years....
Yeah, I suppose. But I also have a first generation Schuberth modular that I paid way too much money for, and it is the noisiest piece of crap I have ever had the misfortune to put on my head. My old Shoei is down right peaceful compared to it. I wear ear plugs whenever I am on a bike.
JD
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For some reason a helmet always fits looser after a visit to a psychiatrist.
Ahhh, but how many motorcycles have you see parked outside a psychiatrist's office? Not many, I'm sure. Motorcycling is the therapy.
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Two materials and both receive the same impact. One cracks and deforms somewhat, the other shows no sign of damage.
Which transmitted more energy to whatever was on the other side?
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<<Yeah, I suppose. But I also have a first generation Schuberth modular that I paid way too much money for, and it is the noisiest piece of crap I have ever had the misfortune to put on my head. My old Shoei is down right peaceful compared to it. I wear ear plugs whenever I am on a bike.
JD>>
I also had the early gray market Schuberth helmet, and I entirely agree with your assessment. Worst helmet I've ever had. I also wear earplugs on any long or high-speed rides. And no, you don't need to replace your helmet if it whacks the ground without your head in it, at least not according to the Director of the Snell Foundation, who said that was an Urban Legend.
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Charlie, honest question as I don't know the answers, but I'd THINK even if the basic materials of the shell and liner are the same, don't you think they may have improved the fabrication techniques?
I'm under the impression helmets have gotten lighter and quieter. I guess I've assumed they've also gotten safer?
And I assume they are just made to meet the standards, Snell, ECE and/or DOT. If the materials improved then I would expect them to use less of the material to make the helmets lighter (which has happened in some cases).
Fabrication techniques. Heck, Arai advertises that they have 15 guys sitting there hand laying the helmet fiberglass. Can't get more old school than that. Same way my 1970's helmet was made.
And EPS forming is still done the same way.
So, yeah there are reasons to buy a new helmet, but, I don't think safety is one of them. Of course, if you are like me and drop your helmet often, then after a while you probably do need to buy a new one :)
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Interesting link on coating a helmet shell with plasti-dip:
https://www.youtube.com/watch?v=o_aingfOl8k
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Of course, if you are like me and drop your helmet often, then after a while you probably do need to buy a new one :)
Just do it the way I do... when I drop mine, it always bangs the shield and not the shell. The shell is spared any damage, but I can hardly see to ride.
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And I assume they are just made to meet the standards, Snell, ECE and/or DOT. If the materials improved then I would expect them to use less of the material to make the helmets lighter (which has happened in some cases).
Fabrication techniques. Heck, Arai advertises that they have 15 guys sitting there hand laying the helmet fiberglass. Can't get more old school than that. Same way my 1970's helmet was made.
And EPS forming is still done the same way.
So, yeah there are reasons to buy a new helmet, but, I don't think safety is one of them. Of course, if you are like me and drop your helmet often, then after a while you probably do need to buy a new one :)
Though standards have changed since the 70's, no?
And there is meeting standards, but don't SOME exceed standards?
:undecided:
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I still have my mid 70's era Arai which i don't wear and the foam is much thinner then what you find in a modern helmet.