A friend of mine, who works as a sales manager in a good bike shop advised me to never buy a helmet that is older than couple of years, and the best thing to do is to buy the current model line, when they arrive to LBS (like fresh bread). Neither he earns from my purchases at his shop, nor he insisted to buy there, and even recommended me a few models that they don't have, so there is no marketing bias in this advise. So the question is, whether a helmet really looses its quality even if it's stored in a bike shop?

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    Sounds like something for Mythbusters!
    – l0b0
    Commented Jun 10, 2013 at 15:37
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    It would be a poor quality helmet that needs to be discarded after even 5 years of storage. Kept wrapped (not exposed to sun or solvents or fumes, and not subjected to "shop wear"), a "new" helmet should be good for 10 years at least. (I frankly have no problem with using a non-lightweight helmet for 10 years, so long as it's taken care of and not subjected to impact. The 5-year replacement recommendation assumes that the helmet is subjected to mildly rough use.) Commented Jun 16, 2013 at 2:16
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    I do not have the answer, but suggest this needs to be decided on science and not anecdotal evidence. I will say that in the world of rock climbing, it has been tested and proven that nylon kernmantle ropes dangerously degrade after 2-5 years even when protected from light, heat and air. Obviously, the more light, heat and air - UV rays - oxidation of the plastics - the faster the rope degrades. In bike helmets, we are talking basically styrofoam with a hard shell. Since when is styrofoam long-lived?! I admit to using a helmet probably far too long. But I suspect helmets are shorter lived that
    – user7246
    Commented Jun 18, 2013 at 16:48
  • @LCTexas Except that places like Snell know who butters their bread. Commented Jun 18, 2013 at 17:11

4 Answers 4


A lot will depend on the construction of the helmet. For example the basic material in the helmet will be some sort of sponge or foam which relies on its texture to absorb sudden impacts; does this degrade over time? For example, a loaf of bread gets its texture from the tiny air bubbles formed while rising and proving, but if left to prove too long, the structure collapses, or, once baked, the bread will harden and not be as flexible.

So it might be with helmet foam; at least, that's the concern, in particular when subjected to sustained UV/sun light. It's certainly not been a concern that manufacturers have been quick to dispel.

But there is another side to this question, not just whether you should not buy an older helmet because it has lost its ability to do its job? Have the helmet construction methods moved on since that helmet was made, simply, are newer helmets better? Are they lighter, stronger, more absorbent, better value, more adjustable?

Many reputable organisations, e.g. the Bicycle Helmet Safety Institute, say not to worry

Most manufacturers now recommend that helmets be replaced after five years, but some of that may be just marketing. (Bell now recommends every three years, which seems to us too short. They base it partially on updating your helmet technology, but they have not been improving their helmets that much over three year periods, and we consider some of their helmets since the late 1990's to be a step backwards, so we would take that with a grain of salt.) Deterioration depends on usage, care, and abuse. But if you ride thousands of miles every year, five years may be a realistic estimate of helmet life. And helmets have actually been improving enough over time to make it a reasonable bet that you can find a better one than you did five years ago. It may fit better, look better, and in some cases may even be more protective.

The Snell foundation concurs:

Hair oils, body fluids and cosmetics, as well as normal "wear and tear" all contribute to helmet degradation.

Although I would hesitate to buy a helmet which can't stand up to sweat, this suggests that it is use that affects the longevity of the item, not its storage.

I'm not a scientist in this area, but while there might be evolutionary reasons in the helmet's construction to merit buying newer ones, just being stored for a few years probably won't be reason enough.

But as I asked in an answer to a related question, why are you planning on wearing it? If you're looking for a cheap helmet because you don't really want to wear it, then an old one will be fine, but if you're genuinely concerned for your safety and you really want something to do the best job, then should you be quibbling over the few dollars/pounds/{currency units} difference?

  • I ride trail - all-mountain a few times a week and want to buy AM helmet instead of my XC one (to be more confident on drops, rock gardens and a little downhill), so I doubt if I should invest time on chasing after the latest models. Anyway, thanks for a great answer!
    – J-unior
    Commented Jun 10, 2013 at 9:22
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    @J-unior Just so you're aware, you can get a decent AM helmet without spending Giro XAR / Troy Lee A1 / POC Trabec money. e.g. the Specialized Tactic or Giro Hex. Commented Jun 10, 2013 at 16:15
  • @J-unior sorry, I'm not familiar with the abbreviation - what's AM?
    – Unsliced
    Commented Jun 11, 2013 at 8:46
  • All mountain. Anyway, I've opened a related question on subject - bicycles.stackexchange.com/questions/16171/…
    – J-unior
    Commented Jun 11, 2013 at 9:13

Buying a "fresh" helmet every couple years sounds a bit excessive. This is based on the personal experience of needing to replace couple helmets due to impacts. Both helmets were at least two years old. One was a direct hard head hit event during a race. The other was being hit by a car. This was back in the 80's. I'm assuming helmets are better today. The helmets did their job.

Multiple factors effecting helmet life. How many hours per year do you ride? Where? UV intensity, temps, environmental contaminants in the air? What degrading risk factors does your helmet get exposed to when not in use? Bottom line: Replace after any suspected impact & if you feel use and/or abuse has reduced the level of protection.

Regarding costs for helmets. More is not necessary better. Replacement helmet just purchased ended up costing ~45usd. Bell Muni. ~10oz, well ventilated, adequate air flow channels, removable visor, the ?tag fit systems is nice, just not a high style helmet used by any ProTour riders.


I think you are concerned with the 'rate of degradation'. I've designed sports helmets recently that use similar materials (EPS for example), but not for so long as to ascertain all aspects of durability. Your biggest concern would be loss in mechanical strength on photodegradation. The rate of change in the mechanical integrity of expanded polystyrene (chain scission is the cause) would depend on the amount of exposure to the sun. If it's in the package, then I expect there should be little change in 5 years, even to the vacuum formed laminate/ thin plastic on the outer most surface.


Styrofoam is not biodegradable. Only where the shell could be cracked is where it would be exposed to UV and high heat from the light degradation.

  • Could you please expand this answer? Some citations or references would be good, and better again if they were related to helmets. Short answers tend to be deleted for lack of depth because they look like an off-the-cuff comment without research or supporting information. Or, you can make comments on the question when you reach the required level of points. Voting to keep because the point is interesting and relevant.
    – Criggie
    Commented Sep 8, 2016 at 0:58
  • Welcome to Bicycles @Robert. I see you've taken the tour; I also suggest How to Answer, since you're writing an answer. Imagine that your answer is being read in isolation. Try to make it as complete as possible, as though your reader doesn't know anything about helmets. For example, what does Styrofoam have to do with it? What does biodegradability have to do with it? What else do helmets contain? What causes degradation? Good start ...
    – andy256
    Commented Sep 8, 2016 at 3:52

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