Helmet life


New Member
Mar 16, 2017
It has been a few years since I cycled, so, as long as a helmet (I use bell and MET) has not been damaged how often should it be replaced.

A common, but conservative recommendation is every 3-5 years.
That's considered a safe interval even if the helmet has seen some exposure to damaging environmental conditions and substances.
Degradation of materials. Polymers can degrade over time and that process can be accelerated with exposure to heat and light. The Styrofoam core can delaminate from the in-mold shell.

As dabac stated, most manufacturers recommend a replacement interval. If you only use your helmet for a limited number short rides per year and carefully store it, it's going to last a long time. How long? That's a good question.

I crashed and cracked a 4-year old Giro that had a lot of hours on it. It did its job well despite having a very high number of hours on it, ridden in all seasons/temperatures.

Giro states this:
"Giro has a general recommendation of replacing your helmet every three (3) years. If you are unsure of the condition of your helmet, or whether it should be replaced, call us at (800) 456-2355 or e-mail us at [email protected] for information on a free inspection."
Bummer, ok, thanks, so for 100% safety regardless of use replace

In fact I have worked out that they are about 6 years old, very little use, shame

thank you
Very little use with good storage conditions (not exposed to UV light and no excessive heat)...they are 'probably' still safe.

Inspect them carefully. The styrofoam does most of the heavy lifting in a crash and it may be just fine. The outer shell's job is to prevent some penetration injuries and keep the Styrofoam liner intact during impact. If it is still bonded/secured to the Styrofoam and not brittle, it too is probably still capable of affording good protection.

Bike shops, re-sellers and manufacturers are all going to tell you to replace your lid more often than absolutely necessary. Product liability lawsuits, more profit and sales and all that expensive stuff.

And in the end, paying $29-$100 for a decent new helmet and peace of mind isn't all that bad in the grand scheme of things.
Those early 3 year replacement cycles are so you'll run out and buy another. If you had the helmet stored then it wasn't exposed to anything that would make the helmet unsafe unless some sort of chemical got spilled on it. Even if you were using the helmet a helmet is good for at least 5 years depending on the individual who is wearing it chemical disposition. But the way you tell a helmet is due for replacement is after a ride and you sweated you may feel like there is fine particles of dirt on your forehead and or hair, and you'll wonder where that came from, it came from the degradation of the Styrofoam and it's time to get a new one, it's still safe to ride for a short time while you shop for a new one. The other clue is if the Styrofoam appears to have a depression where one shouldn't be, time to get another; and one last clue is if there are cracks forming on the Styrofoam. Or did you crashed and smacked the helmet it will probably need to be replaced. And one of those 4 conditions is a clue to get another.

The crashing thing is up to the individual's knowledge about what to look for in the way of damage to the helmet, Styrofoam depression and cracks are a big clue, but sometimes you may not hit all that hard and the helmet could still be good, but if you're not sure better safe than sorry and replace it.

Of course if the helmet you're talking about was stored since the 80's well you may want to buy a new one. Newer helmets made in the late 80's and onward the companies treated the Styrofoam to prevent UV from doing as much damage as they use to get.

Most of my helmets when I lived in California's Mojave Desert area, where it would get very hot and a person sweats a lot, my helmets lasted 6 to 7 years, since I moved away from that area and now live in a more cooler climate my current helmet is 8 years old with no signs of degradation going on. I am on my second set of pads, if the second set of pads go bad before the Styrofoam does then I'll probably replace the helmet.

You can read more about what I said here if you're having difficulty believing what I said: http://www.bhsi.org/replace.htm

Keep in mind, you have marketing forces at work, and they want you to buy stuff over and over, and helmet plays in the heart strings, so by golly better replace that thing every 3 years so the helmet company can make more money...while you lose more money.
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If a helmet is unused, what can wear out

Plastics age, usually through becoming more brittle.
More brittle means they'll soak up less energy before they shatter. Means more (risk of) energy transfer to your head.
More energy means more injury.

Exposure to heat, UV-light, ozone (in particular) and a bunch of other chemicals will speed up ageing.
Storage in dark, dry, and cool conditions will slow down ageing.

The 3-year recommendation is given with unknown(=assumed poor) use and storage conditions being used.
Follow that and you don't need to think about anything else than impact damage to the helmet.
Want to go longer, it becomes a judgement call.
How often did the helmet get left in the car?
Hanging next to the furnace?
Etc etc.
The plastic outer helmet cover does not become brittle, after every time I replaced a helmet I would take a hammer to the helmet and proceed in bashing it in, and the plastic was never brittle...I bash my helmets in for fun! But despite the fun issue the plastic of various models and regardless of years made and ages never had any brittleness. The cheap child like helmets you would buy at Walmart those will either warp or start peeling away from the Styrofoam, but even those didn't become brittle doing the hammer bashing fun. I took a helmet that was at least 15 years old and bashed it in and the plastic wasn't brittle. We have plastic stuff in our cars that have varying thicknesses and those are exposed to heat, but they're design to be worn for helmet coverings because they're too thin and not rigid enough survive the intense summer heat of various climates for 20 years and more without cracking. The old plastic car interiors from the 70's and early 80's would before they started to make them more uv resistant and heat resistant, but I haven't seen cracked dashes etc for a while now.