Do helmets really expire?

[Max]

I recently listed 2 helmets in good condition on the classifieds and was asked a question as to their age by one reader due to them possibly having expired. I was a little oblivious about the topic so I went looking for some studies that actually tested this and not just normal manufacturer talk trying to sell more gear. I am including the links below but curious as to others experience? Also, just a caveat, this is not discussing helmets that have taken big hits. 

https://link.springer.com/article/10.1007/s10439-017-1842-4

https://asmedigitalcollection.asme.org/biomechanical/article-abstract/138/4/041005/371203/Age-Does-Not-Affect-the-Material-Properties-of?redirectedFrom=fulltext

 

[IceCreamMan]

1 hour ago, Max said:

I recently listed 2 helmets in good condition on the classifieds and was asked a question as to their age by one reader due to them possibly having expired. I was a little oblivious about the topic so I went looking for some studies that actually tested this and not just normal manufacturer talk trying to sell more gear. I am including the links below but curious as to others experience? Also, just a caveat, this is not discussing helmets that have taken big hits. 

https://link.springer.com/article/10.1007/s10439-017-1842-4

https://asmedigitalcollection.asme.org/biomechanical/article-abstract/138/4/041005/371203/Age-Does-Not-Affect-the-Material-Properties-of?redirectedFrom=fulltext

 

Time alone will degrade materials over a long period of time and depending on how they have been stored. However, what does degrade a helmet is usage. 
 

For the most part it’s marketing blurb designed to liberate you from your cash. And we lap it up. Of course. Gotta have the best. 
 

that said I would be hesitant to buy a second hand helmet as the history of it is impossible to determine. 

[Mohs]

For most riders, it's recommended to change a mountain bike helmet every 3 to 5 years, regardless of whether it's been involved in a crash. This timeframe accounts for the natural degradation of materials over time due to factors like exposure to sunlight, sweat, and general wear and tear. If your helmet experiences a significant impact or shows signs of damage, it should be replaced immediately, even if it's within the 3 to 5-year range. Regularly inspecting your helmet for any cracks, dents, or other damage can help ensure your safety while riding.....This is Chatgbt talking  🤖 

IMHO: If its that old, then rather donate your helmet to cycling development clubs...or your annoying Cousin.  

[WIPEOUT 1000]

I’ve also often wondered about this. Poly Styrene is an environmental disaster specifically because it takes forever to decay naturally. I suspect that the polycarbonate shell is probably susceptible to UV decay and that might be the determining factor.

[Carlos Roberto]

Did anyone have a chance to read the articles in the original post? I believe the first one concluded that over a period of 24 years the helmets did not degrade significantly. Wipeout 1000 does make a good point about polycarbonate which degrades under UV with pronounced discoloration. As we all know ChatGPT is only as good as the info it is fed from the internet.  https://www.sciencedirect.com/science/article/pii/S2238785421003793

[Me rida my bicycle]

There's just to many factors to put a time frame on a helmet.

Some people ride every day some ride once a month. Some people clean the helmet before they put it away, some people can find their helmet in the dark. 

 

[MajG]

So if helmet spends 2 years in bike shop, I purchase it and use it once a week for 1year...without falls, am I suppose to buy a new helmet as per the 3 to 5 year recommended usage period?

 

Or is it 3years usage time, if that's the case it can be used for 10 years

[Max]

I think this is why I went looking for some real world studies having used actual helmets of varying ages, and these were used too, so there would have been sweat and UV exposure impacting the results.