Ive had it happen and provided the foam cell looked like it hasn’t compressed I’ve worn it. With no weight in the helmet I doubt it would compromise it but I haven’t tested the theory.
Not sure there is a definitive answer and I suspect the manufacturer would err on the side of caution if asked.
How could you tell? Damage to the EPS foam would surely occur on the face adjacent to the inner face of the outer shell? Where you can't see it...
Is there any bad marks on it?? (is the outer shell compromised)
Did the GoPro take the brunt of the impact?
Every one is going to have a strong opinion on this.......I would need to see it to decide if "I" would wear it or not.
How would Joe Public tell? A tiny scratch on the face of the outer shell may be just a scratch. But serious damage may be concealed within...
I once witnessed someone smacking an old helmet with a sledgehammer to see how compromised it might have been after numerous bashes and scrapes from knocks and drops etc. I was surprised at just how many whacks it took to make any real impression on the integrity of the lid. Lid sellers who advise replacing the lid after a drop...well, they would say that wouldn't they? A manufacturer once advised (after I'd dropped my lid) not to worry as the real compromise to safety is owners who ride regularly, and do things like keep their sweaty gloves inside their helmets when not in use, need to change lids every 2 to 3 years because it's partially the effects on the padding which can harden with age and I guess biological attack, that compromise the energy absorption of the impact protection. This can lead to brain injuries even if the outer isn't compromised. As long as there's no obvious cracks or delamination of the shell (unlikely from a drop) I'd crack on unless you want to use it as an excuse to buy a nice shiny new model.
The resin bonding process of modern lids means that you're rarely, if ever likely to witness delamination that could sometimes occur with much older GRP lids.
I have dropped mine several times and despite one or two minor scratches, still wear it. I change it once every 5 to 6 years whatever the apparent condition looks like just for peace of mind on the inner shell effectiveness. If I wore it daily, I'd be changing it every 2 to 3 years. You pays your money and makes your choice but a drop like that is very unlikely to do any real damage to the lid's integrity.
How were you able to tell?
It training we always said, the price of your helmet indicates the value you put on your head.
The 1970's Bell helmets advertisement? There are many cheap modern helmets that score higher on SHARP than helmets four times the price - MT Revenge vs Arai Astro...
Price is not always an indicator of quality (nor protection - check out Dexter Ford's findings in his 2005 article in Motorcyclist magazine on helmet protection...). I wonder what Thorsten Veblen might think browsing threads on UKGSer... particularly the ones where "reassuringly expensive" pops up...
Ride magazine did a thing on this a few years ago. Once there is no damage on the outer shell and the inner hasn’t been compressed by a head during the impact the helmet should be ok. The inner once compressed doesn’t expand again so would not be able to absorb the shock of impact again. If there is no head in it the inner cannot be damaged in this way. JJH
Expert's deduction or journalist's opinion?
Please, unless you fully know what you're advising someone when it comes to safety it's best not to advise at all.You're literally putting someones life into your own hands at that point. The helmet shell is not the bit that would make your helmet damaged - it's the interior that takes the impact, the bit you cannot see. If the shell is cracked it's 100% scrapped, but there's many helmets which are totalled inside and look absolutely brand new inside and out.
Perhaps the best advice on the thread...
This!
If there's nothing to compress both sides, how does the polyystyrene inner get damaged?
As an aside, have a look at most spills - the head is pretty much the last thing to hit the ground in most, if it's the first, it's the neck that'll go before the skull.....
D
Is there an assumption in this thinking that the EPS foam gets damaged between the sandwich of helmet shell and wearer's head? I'd have thought that the helmet's own weight would be enough in a 4-5ft drop to flex the shell and deform the EPS?
Because the shell deforms absorbing some energy before contacting and compressing the polystyrene, the shell returns to it's original shape leaving an unseen and unknown compression.
The polystyrene doesn't need to have a mass on the inside to allow that compression on the outside because the helmet has stopped on impact.
You're overthinking Newton's law
That's the reason OP buys a new helmet.
That's very true, Arai being a very humble Japanese run company definitely want to make money, but for now they still refuse to make a flip front or a helmet with an internal sun visor - they could do this obviously but they're reducing safety which they don't want to do, fair play! Only company so far to make a helmet with internal sun visor which has the same protection is Shoei, they raise the front of the shell slightly, keep the same amount of protection inside as per normal =)
Flip front helmets are still opening on impact, I think there's extremely few on the Sharp testing for example which don't have a 100% pass rate, and even those that do have a 100% pass rate on the chin bar not opening on impact, they only get tested a certain amount of times( not sure the answer to how many) but over 100 tests, I'm sure even those helmets won't have a 100% success rate!
Is it 7 tests in SHARP? I'd probably be replacing my helmet before my 100th crash regardless...
OP - get a new helmet.