cross-posted from: https://sh.itjust.works/post/26471848
this post was submitted on 11 Oct 2024
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The foam really doesn't degrade with age, that's a myth. It's basically the same material as Styrofoam.
Definitely replace if it's been crashed in and took a hit. If you're unsure, some of the fancier Japanese brands will inspect a helmet to tell you whether it's still good to use.
false, they do degrade with age and use. source: https://youtu.be/_nbQsnUvlo4
Hitting old foam with a hammer so that it shears apart is dramatic, but that's not the kind of force that it sees in actual use, and not a scientific test.
Here's a study on old used bicycle helmets which use the same materials: https://pubmed.ncbi.nlm.nih.gov/26902784/
It found no difference in impact attenuation properties.
The point in the video that you are missing is that the material when new, has oils that makes it spongy and more effective. Those oils evaporate with time. The demonstration with the hammer is just to show very casually how brittle the material becomes compared with a new one, and the difference is evident.
The study you linked, as yourself said, is for bicycle helmets. They are not designed to protect you against the same amount of force as a motorcycle helmet.
edit: typo
But they're made of the same material so it shouldn't make a difference. They also didn't hit the foam with a hammer in the study, by the way.
To the point of FortNine's accuracy in the figures, Ryan says himself that he's not aware of a proper study performed on used motorcycle helmets and he has his own personal formula, so... reasoned but not a source of scientific truth.
They are not designed to protect you against the same amount of force as a motorcycle helmet. That study just proves that expired bicycle helmets are still good for bicycle accidents, not motorcycle accidents. I rest my case.
You rest your case? You haven't presented any real evidence in support of it.
You are free to throw your helmet away every couple years if you want to.
Wait, are you saying that helmets don't expire, and that's just something manufacturers tell you to sell more helmets? Other than the obvious parts that eventually break/wear. My instructor for my last motorcycle license test told us that they expire during training.
EDIT: I did some quick research and I can't find any definitive answer, but I found a few law firms stating that helmets expire and that could affect compensation in a crash, so I am making the assumption that infers legal precedence which means at one point there was scientific evidence brought forth to prove that helmets deteriorate to show that the rider was negligent. NAL.
I don't know if they tell us that just to sell more helmets, but I'm fully convinced there is no such thing as a shelf life for a helmet. That's not to say there aren't good reasons for replacing a helmet in general, like wear and weathering to the shell / visor / pivot points, advances in features and tech. Personally I wouldn't buy a used helmet because it's tough to tell if it took a drop that could have compressed that foam. And yes there are people and curricula that will tell you a helmet lasts only 2-4 years, even the MSF: https://smarter-usa.org/wp-content/uploads/2017/06/26321_MSF.pdf I was a RiderCoach myself, and I think that is so dumb. Could you imagine paying $300+ every two years to replace a good helmet with no damage? That's more than than the depreciation my bike has taken while I've owned it. I'm interested to see the legal reasoning presented for compensation based on helmet age. To me that doesn't make a ton of sense, but a lot of questionable logic has factored into judgments in the past.