CarinusMalmari

That remains to be seen, I'm not anywhere near worth it to wear a helmet because it will safe me a headache and some scratches every few decades. But then again, I'm not inclined to behave irresponsible on a bicycle and, say, start riding 24-32 km.h in slippery multi-use spaces, so I might fall a lot less than certain people.


It's actually pretty clear they're not very effective. The fact that decades of research failed to produce proof of a significant positive effect on the outcome of cycling accidents is a very good indication of that.

CarinusMalmari

And it does this by crushing/compressing the foam, not by shattering into pieces.


Well, there are big differences between cycling and riding a motorcycle, and between the helmets that are used for respective activities. Your assumption is somewhat devoid of proper reasoning.

wphamilton

The only problem with fragmenting is the degraded protection on a second impact or bounce. Breaking apart doesn't mean that it did or did not work to mitigate injury, but it is one of the stronger criticisms of current helmet design.

CarinusMalmari

Well, my reaction was more to preemptively mitigate reactions of the type "Gasp, the helmet must have saved his life". Truth is that the type of accident he described more often than not results in no or minor injuries, regardless of helmet use. For a Dutchie it was fairly strange to see how people over-react to what probably counts as a fairly minor bicycle crash around here, when I first started to get aware of cycling in certain other cultures.

Mvcrash

Actually, they are designed to do the exact same thing as a motorcycle helmet, just not at the same speeds. Helmets simply extend the distance, and as a result, the time it takes your head to slow down from whatever speed you were moving, to Zero. Hitting the pavement, instant stop. Wearing a helmet adds time and distance to make the slowing down take longer as the helmet absorbs some of the energy.
Football helmets do the exact same thing. Energy absorbtion over time and distance. When football players contact each other, it is just another crash (slowing down). I'm not sure how they are going to fix it.

Mvcrash

I make no assumption. Check the inside of a MC helmet and then check your bike helmet. I have also removed many helmets from dead folks, and investigated the cause of death, have you? As I stated, they function the same way, absorb energy over time and distance. The physics does not change.

Mvcrash

The cracking of the plastic takes energy. Energy that does NOT get transferred to your head.

rydabent

carinus

It is very apparent that your dont understant the dynamics of a crash. Look a videos of sport car crashes. They tell you that the reason the person was protected is the fact that the cars came apart and dispersed the force of the accident. It is not the function of a helmet to be in perfect shape after a crash. The helmet performed its function if it does reduce G loads and breaks apart.

wphamilton

Not enough to matter either way. If it WAS effective, the foam cracking that is, then you'd design these helmets to crack into a thousand pieces inside some confinement instead of designing them primarily to crush on impact. It can't be entirely avoided though, or at least it isn't for most helmets - almost always with a strong enough impact these helmets will shatter. Only a couple of problems with that, not having anything to do with how it absorbs impact. First, simply that broken off pieces aren't there when your head hits a second time. Second, the shattering due to shear force is likely to exacerbate rotational forces - which are the greater danger for concussions than are linear impacts.

Mvcrash

First, his head has already slowed down as the plastic absorbs energy. You make the assumption of the secondary impact. Second, there was no "shearing force" or "rotational force." He simply fell to the ground accelerated by gravity. Lateral and horizontal acceleration being independant, his head fell about 6 feet. I'm sure you can calculate his head impact speed with the pavement yourself. Also, his head did not hit first, his shoulders did which slowed him down before his head hit.

Mvcrash

I am NOT trying to advocate for or against using a helmet. Do as you please. I was just giving an exmaple as to why I do. I also commonly refer to a helmet (when looking for one in my house after the wife makes me play hide and seek) as my BRAIN COVER.

CarinusMalmari

What do you expect? That I have some foam induced revelation? Yes I know there are many similarities, but the differences are much more interesting as far as I'm considered.

It might be a good idea to use knowledge you acquired this way to make arguments instead of using it as some sort of cheap rhetorical intimidation technique. Also remember we all get to be super-hero ninjas with a science degree here. It's the internet after all

But apparently the effectivity does, which is kind of the important thing here. Bicycle helmets have not proven to be very effective in protecting the head.

wphamilton

The hard shell allows the motorcycle helmet to slide and to protect against multiple sharp impacts. Absent any vertical surfaces that you collide with, the speed of the vehicle doesn't really have much to do with the size of the initial impact, nor the impulse delivered, since that is completely dependent on the initial height.

It's a big "if" since you have curbs, signposts, parked vehicles etc, or even an up-sloping road surface. All of these will increase the impact. But on a flat smooth road it's simply the instantaneous velocity of free fall. The big issue, after the initial free fall impact and impact on vertical protrusions, is friction. Too much friction, or a "grabby" shape, will cause rotational acceleration on the head and contrary to popular understanding, that's where we get serious concussions. Motorcycle helmets are far superior in this regard, and would be superior even at normal bicycle speeds. The only reason we don't wear them on bikes is the cooling air flow.

wphamilton

I'm not making assumptions - I'm relaying the current scientific understanding of bike helmets. You can look back in this thread for a recent cite from one of my posts.

There is shear force from the friction of the helmet against the ground, due to his forward velocity. (and also due to any angular impact against the helmet)

I don't know who "he" is or what part of "him" hit first, I'm speaking in general. However, I can tell you that if I fall from bicycle height on either a low side fall or faulting over the bars, my head won't hit at all and if I do it right my shoulder won't be taking up most of the impact in either case. It doesn't matter - I'm talking about helmet impacts against the ground.

I-Like-To-Bike

What did you learn about helmet effectiveness from your investigation of the helmets worn by folks who died while wearing them?

Jiggle

I once rode by some people who were riding horses on the side of the road. They shouted something at me so I turned around and asked what was up. A woman yelled at me that I was stupid for not wearing a helmet. Being unwitty, I just rode away without sending a retort, but the rest of the ride I was pondering whether it was safer to be like me, helmetless on a bicycle with my head 5 feet off the ground, or like her, helmetless and on top of an unpredictable beast with her head 10 feet off the of the ground....

I know, cool story bro.

mconlonx

Having been around horses for some of my life, safer on a bike without a helmet than on a horse without one.

Mvcrash

Please explain the difference other than the MC creates much more energy than the Bike.

I have never mentioned a science degree just the fact that I have experience investigating crashes.


here ya go.

IIHS.ORG


you can read more anytime.

Mvcrash

Simply, you have a better chance of survival with a helmet than without. Which would seem obvious to me.

Mvcrash

But safer on both with one.

CarinusMalmari

Well, we where talking helmets, really, and i think it's fairly obvious what the differences are. Compared to motor helmets, bicycle helmets are flimsy contraptions than made concessions to improved weight, ventilation and comfort over protection, to the point where bicycle helmets lost most of their protective value. But, as luck would have it, cycling is typically a low-speed and therefore intrinsically safe activity, due to the low kinetic energy involved. So helmets aren't really needed in the first place.

I don't think they test bicycle helmets like you think they test them.

Mvcrash

I don't think bike helmets should be mandatory. I don't think they are the end of all head injuries. I think that they give you a better chance of avoiding a serious brain injury.
If you think they don't help at all, don't wear one. My thought is that if they save one person from one brain injury.....why not.


https://www.iihs.org/iihs/topics/t/pe...facts/bicycles

I-Like-To-Bike

Very simple indeed. Your approach to logical thinking is also obvious.

Brennan

Confronted by another helmet nanny today. Riding along with my wife, both of us un-helmeted, my wife waves at a cyclist going the other direction. The guy returns the greeting with a smug look while pointing to his helmet. So obnoxious.

shipwreck

I've never been really influenced or impressed by either sides arguments on the helmet subject. However, I would have to say that the tendency of the pro helmet safety shamers to do things like that tips the scales to the side of the non helmet your a fool to believe the helmet myth crowd who don't tend to do things like that. As someone who REALLY dislikes people telling me what to do, that's a win for your side.

Now watch tomorrow on my fast ride that I wear a helmet on, as I get cornered by someone who wants to tell me all about rotational injuries and how wearing some Dumbo's feather on your head makes cycling look dangerous to the general public.