I know they need to be replaced if you crash… But does a couple years of sweat and sun exposure weaken the helmet and require replacement?
Yes
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Wow. Good to not learn that the hard way. Is there a recommended time? Every year, 2 years, 5 years etc.?
The foam will weaken from atmospheric exposure over time. It embrittles and looses some of it’s ability to absorb energy. I’ve seen some helmet mfgs. recommend that their helmets be replaced every 2yrs (boy, they would love that), but haven’t actually seen any data on the degree of degradation, or after what point a given helmet would fail a CPSC impact test.
There is not a point where a helmet is no longer legal for races. You can still compete in a pre-CSPC, Snell certified, Bell Biker helmet from the '80s.
Personally I replace a helmet every 2 or 3 years depending on the use.
If the foam in the helmet looks dry or crumply, I would replace it.
With that said, I have a helmet that I normally use on my MTB that I’ve had for about 7 years now which is in terrific condition cuz it’s rarely used.
jaretj
For my motorcycle helmets, I would replace them whenever a new Snell standard came out. About every 5 years. For the bike helmet I’ll do the same unless other parts wear or the smell gets too bad.
Have you any data to support this opinion? I’d be interested in seeing some not provided by either a bike shop or a helmet maker.
the DOT certification on a motorcycle helmet is only good for 3 years from date of manufacture (year and month appear on a sticker inside the helmet, under the comfort liner). sweat and UV exposure are supposed to degrade them past DOT spec within that time.
i’d assume cycle helmets are similar, or possibly need to be replaced even more often, as you’d likely sweat a lot more in a cycle helmet than a moto helmet.
cheers!
-mistress k
This isn’t hard data, but at least it’s info that is not from a manufacturer or bike shop:
From: 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. UV 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, maybe the UV inhibitors are 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.” That is highly unlikely, 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. EPS is a long-lived material little affected by normal environmental factors. Unless you mistreat it we would not expect it to “dry out” enough to alter its performance for many years. In sum, we don’t find the case for replacing a helmet that meets the ASTM or Snell standards that compelling if the helmet is still in good shape and fits you well.
I had a nasty crash three weeks ago where my head and right shoulder took the full brunt of the fall at 26mph. I had been intending to replace my helmet since it was from 2003 but didn’t get around to it. The plastic shell kept the helmet in tact but split the Styrofoam into 3 big pieces. Definitely saved my life. No concussion and no problems other than bad road rash on the rest of my body. Just my experience with older helmets
Yep I’ve seen this site before. I agree with it. I don’t trust a helmet manufacturer’s recommendation for replacement because of the conflict of interest, and I’ve never seen any third party evidence that these things need replaced regularly. The exception is if you change kits or bikes and your helmet no longer matches.
The helmet makers claim they should be replaced every 2-3 years. I highly doubt that the foam will degrade within that time, though I have noticed some serious degeneration of helmets that I left out in the sunfor a while, which caused them to warp.
Look at it like this, though. Is it worth the risk to not buy a new helmet? Are you willing to risk your health and vitality over $50 every few years?
I would say, if your helmet looks like it needs replacing (warping, fading, cracking, embrittlement), then it should probably be replaced. If it looks fine, I wouldn’t worry about it.
Luckily for me, my helmets always have a habit of dying before their manufacturer-specified time limit runs out. 
I would go one step further than this and suggest that the condition of the plastic shell has little to do with the structural integrity of the helmet.
A new helmet would have broken up as well. I had a similar experience last year and my helmet was around a year old. It’s normal for the helmet to not survive the crash as long as it protects your head. I have a couple of retired helmets that I keep as loaners. They’re pretty old but still fairly sound and I wouldn’t feel any less safe in one of those over a new one.
If you are leaving your helmet out in the sun all day than yeah, it probably needs replacement. My rule of thumb is if it looks old, crappy, and the liner is falling apart - trash it. Otherwise, keep on wearing it. Manufacturers warnings are probably just to increase the bottom line.
My guideline for replacing a an older helmet is, if the accumulated funk is offending my nose when I put my head down, it’s time to get a new helmet. That comes up ~every 2.5 years for me personally.
Thanks everyone for the advice.
Helmets are like Formula style race cars and NASCAR cars. they are intended to absorb the impact and protect the contents.
My understanding, and personal opnion is a helmet is a one crash toy. If yo hit your head, either pursue the crash replacement policy for that mfg, or make a trip to the bike shop and support the economy.
I replace mine every three years. Everyone may be right that helmets will last for a very long time (more than the 3 year replace recommendation) however if spending an extra $150 every three years better protects me (and my family) then it’s worth it. I’d hate to find out the hard way that my helmet didn’t protect my head. Let’s be honest, almost every triathlete on here has blown money on some useless junk. Just skip buying that new “fad” shoe…
Look at it like this, though. Is it worth the risk to not buy a new helmet? Are you willing to risk your health and vitality over $50 every few years? Arbitrarily making decisions based on a possible safety fear could land a person in the poor house with no enhancement on actual safety.
My guess is a helmet that’s old is still as good as a new one unless it’s been bumped around. Foam is a very long-lasting material.
It is telling that motorcycle helmets are only good for three years, based on a post above, but perhaps there is a different reason for that.My understanding, and personal opnion is a helmet is a one crash toy.This is a given; a helmet that takes a hit absolutely must be replaced.