The CycleChat Helmet Debate Thread

[ufkacbln]

I wonder if that's a bit too long to have printed on a jersey?

You can get 5XL TShirts

 

[bianchi1]

I used to wear a helmet whenever i cycled as a matter of course, never paid it any thought one way or another. One summer a couple of years ago, on one of those rare 30 degreesC+ days, I was riding home from work and my head started to feel really unpleasantly hot, to the extent I felt a bit dizzy. It occurred to me that I would be safer if my concentration wasn't compromised by overheating. So I took the helmet off, and the next day I didn't wear it. I noticed a couple of things: firstly the feeling of the wind in my hair was pretty wonderful, and secondly I felt more vulnerable, which changed the way I rode - for the safer (fairly obviously). Anyway, the helmet went back on in the winter and I thought no more about it. Then the next summer I thought about going helmet-less. I left it at home one day and again I had the feeling that I was riding differently, riding better. I did some more reading about it and with the help of forum threads like this one, I learned a great deal. Now I don't ever wear a helmet and I am certain that I am a much better and safer cyclist for it. So, thanks to you all for feeling strongly enough to keep posting here, its helped at least one person make a better choice.
The irony is that by choosing to not wear a helmet, I am certain that I have spent, and do spend, more time thinking about safety that the vast majority of helmet wearers.

So how did you change your riding specifically?

 

[pjm]

So how did you change your riding specifically?

I think I generally sharpened my focus, thought more carefully about risks I was taking. Maybe a little like the difference between riding on wet vs dry roads.

 

[philepo]

This is a debate moved from here: https://www.cyclechat.net/threads/choosing-a-cycle-helmet-commuter-or-road.197015/post-4187777

As I understand it, the hard shell is not only to keep the foam on, it's also to distribute the inital impact through more of the foam to make it less likely to crack or be pierced.

That makes sense to me, agreed!

Also, there's still the same deceleration force of the brain which is why helmet-wearers still get concussed, although it's spread over a greater time.

Sorry, I don't think physics lines up with that view.

"They still get concussed " could just as easily be written as 'concussed cyclist avoids serious brain damage and only got concussion' OR 'concussed cyclist would have avoided concussion had he not been wearing a helmet that stuck out further than his own head and hit the road'. It's pot luck.

Before anyone gets cross, lets agree not to argue about whether helmets are safe or should be worn - just the principle science that allegedly makes them effective. Assuming the foam crushes as it's supposed to, then the deceleration of the head takes place over, say for the sake of argument 10 mm, as opposed to perhaps 1 mm of skin and skull deflection. The force is directly proportional to the deceleration, which over the longer distance will be reduced (force = mass x change in velocity / time taken to change velocity). Ergo, reduced force.

The other thing a helmet would allegedly do is distribute the point load that would normally occur over a wider area (the hard shell does this), so lowering the stress level.

I think the reason so many people dismiss the unseated cyclist's cry of "my helmet broke therefore it saved me" as rubbish - and proof that helmets are weak and pointless - is because they don't understand that the energy used to break the helmet did not enter the brain and therefore was a good sign, not bad...

 

[mjr]

Assuming the foam crushes as it's supposed to, then the deceleration of the head takes place over, say for the sake of argument 10 mm, as opposed to perhaps 1 mm of skin and skull deflection.

Ignoring the other problems (including mine, more than likely), this appears to switch from considering deceleration of the fluid-suspended brain to considering deceleration of the whole head!

 

[martint235]

I think the reason so many people dismiss the unseated cyclist's cry of "my helmet broke therefore it saved me" as rubbish - and proof that helmets are weak and pointless - is because they don't understand that the energy used to break the helmet did not enter the brain and therefore was a good sign, not bad...

But if the energy is effectively being absorbed and kept away from the brain, the testing would be simple to prove that?

 

[mjr]

[QUOTE 4190180, member: 45"]On Jeremy Vine at the moment. Nothing to hear, just the same arguments as in this thread.[/QUOTE]
Thanks. 6music is Now Playing "Walk Away Renée" The Left Banke - which seems like a good approach to Jeremy Vine

 

[philepo]

Ignoring the other problems (including mine, more than likely), this appears to switch from considering deceleration of the fluid-suspended brain to considering deceleration of the whole head!

The brain reacts to the whole head - its a linked system, not separate. Stopping a head in 1mm of travel will mean the brain has to absorb the energy that wasn't absorbed by 10 mm of foam.

But if the energy is effectively being absorbed and kept away from the brain, the testing would be simple to prove that?

I presume it does. But then we know F=ma so what's not clear?

Saying that cycling isn't dangerious and should need sarty gear is absolutely fine with me. ANd I don't want to be told to wear one, I only do when surrounded by cars. But trying to say that helmets don't work (in an impact that was going to happen anyway.. ignoring risk compensation etc) is futile.

 

[martint235]

I presume it does. But then we know F=ma so what's not clear?

Saying that cycling isn't dangerious and should need sarty gear is absolutely fine with me. ANd I don't want to be told to wear one, I only do when surrounded by cars. But trying to say that helmets don't work (in an impact that was going to happen anyway.. ignoring risk compensation etc) is futile.

But it's obviously not so simple is it? If it was then the multi-million pound helmet industry would have conducted testing to provide proof of the ability of helmet to protect the wearer. This data would then be made public.

 

[ufkacbln]

This is a debate moved from here: https://www.cyclechat.net/threads/choosing-a-cycle-helmet-commuter-or-road.197015/post-4187777




That makes sense to me, agreed!




Sorry, I don't think physics lines up with that view.

"They still get concussed " could just as easily be written as 'concussed cyclist avoids serious brain damage and only got concussion' OR 'concussed cyclist would have avoided concussion had he not been wearing a helmet that stuck out further than his own head and hit the road'. It's pot luck.

Before anyone gets cross, lets agree not to argue about whether helmets are safe or should be worn - just the principle science that allegedly makes them effective. Assuming the foam crushes as it's supposed to, then the deceleration of the head takes place over, say for the sake of argument 10 mm, as opposed to perhaps 1 mm of skin and skull deflection. The force is directly proportional to the deceleration, which over the longer distance will be reduced (force = mass x change in velocity / time taken to change velocity). Ergo, reduced force.

The other thing a helmet would allegedly do is distribute the point load that would normally occur over a wider area (the hard shell does this), so lowering the stress level.

I think the reason so many people dismiss the unseated cyclist's cry of "my helmet broke therefore it saved me" as rubbish - and proof that helmets are weak and pointless - is because they don't understand that the energy used to break the helmet did not enter the brain and therefore was a good sign, not bad...

It is simple


We are allowing manafacturer to produce inferior goods and then ironically accepting that failure as a good thing

 

[philepo]

But it's obviously not so simple is it? If it was then the multi-million pound helmet industry would have conducted testing to provide proof of the ability of helmet to protect the wearer. This data would then be made public.

No, providing proof is not simple and is expensive. But providing a scientific rationale is simple and does support the isolated example of a chap hitting his head on a solid floor with and without foam inbetween.

It is simple


We are allowing manafacturer to produce inferior goods and then ironically accepting that failure as a good thing

You must be winding me up with that one?

 

[martint235]

No, providing proof is not simple and is expensive. But providing a scientific rationale is simple and does support the isolated example of a chap hitting his head on a solid floor with and without foam inbetween.



You must be winding me up with that one?

Have you read through this thread?

If you want to convince people that a helmet is useful in a given situation you need to evidence that claim. Just saying that wearing a helmet while a man hits his head on the floor is meaningless. Is the helmet saving his life? Is it making his head bigger and more likely to hit the floor? Is it actually doing anything? Anything to back that up?

In the normal world of selling something via a claim that it helps, evidence is usually provided. Vaccines are tested extensively to show that they protect against what they claim to protect against whilst not doing other harm. Head and Shoulders is tested to prove that it does in fact reduce dandruff (you can even see the datasets if you can be a***d). And then we have cycle helmets. But cycle helmets are different because if you read through this thread, you'll find that by and large manufacturers don't make any claim about how much they'll help in crash, instead the large bylines are about comfort, aerodynamics etc.

 

[ufkacbln]

You must be winding me up with that one?

Not at all, it has been fully covered before - Please see the previous posts

It is a fact that helmets are less effective and these breakages are simply one of the things that evidence this
A few points to summarise:
Modern helmets have less absorbent material as the number of vents increases, reducing the ability to absorb energy

As the amount of material decreases, the remainder has to be denser to support the shape and form, again reducing the ability to absorb energy

The use of carbon frames to support the ever decreasing material, results in bridges that are mainly carbon with little absorbent material that crack and fail when impacted

.. and that is before we start with snag points and other design faults.


The standard for helmets was the Snell B95, and 15 years ago, most helmets passed this

The modern helmet is simply not capable of meeting this standard. As a group we have allowed the cycle helmet's protection to decrease, swallowed the marketing claims (Kask's total security for instance) and like good little consumers paid an increasing sum for a less effective product.

 

[philepo]

Have you read through this thread?

Yes I had a flick through the pseudo science !

If you want to convince people that a helmet is useful in a given situation you need to evidence that claim. There is, impact tests. If you want real human tests, then no, err, there isn't, because that would be unethical. Just saying that wearing a helmet while a man hits his head on the floor is meaningless No it isn't, it is plain fact. If you want to argue that he would be less likely to hit the floor etc, then fine. But if his head DID hit the floor, then they help.. Is the helmet saving his life? Maybe maybe not, but probably maybe Is it making his head bigger and more likely to hit the floor? Good point, could be in some cases Is it actually doing anything? Yes. Hard shell distributes point load to a lower stress on skull. Deformation of the foam inside uses energy that would otherwise enter the brain. Anything to back that up? Yes, physics.

In the normal world of selling something via a claim that it helps, evidence is usually provided. Vaccines are tested extensively to show that they protect against what they claim to protect against whilst not doing other harm Therefore medicines are very expensive while new and helmets are cheap. Head and Shoulders is tested to prove that it does in fact reduce dandruff (you can even see the datasets if you can be a***d). And then we have cycle helmets. But cycle helmets are different because if you read through this thread, you'll find that by and large manufacturers don't make any claim about how much they'll help in crash, instead the large bylines are about comfort, aerodynamics etc. They don't want to get sued and if they pass the relevant test then that is that. What more do you want? Human sacrifices ?

Not at all, it has been fully covered before - Please see the previous posts

It is a fact that helmets are less effective and these breakages are simply one of the things that evidence this Breakage only evidences that the impact was severe and energy has been dissipated before it got to the brain (unless it was a faulty product)
A few points to summarise:
Modern helmets have less absorbent material as the number of vents increases, reducing the ability to absorb energy Yes, but if they pass the same tests (i.e. deceleration was under what has been decided as harmful) then that's fine. If they didn't then that wouldn't be fine. A non-issue surely.

As the amount of material decreases, the remainder has to be denser to support the shape and form, again reducing the ability to absorb energy Yes, this makes sense, unless they have found a better material or the present one still results in good deceleration protection and impact strength.

The use of carbon frames to support the ever decreasing material, results in bridges that are mainly carbon with little absorbent material that crack and fail when impacted The carbon bridge takes the load, the load is transferred to the adjacent plastic/carbon, this load then enters the foam underneath and is distributed to a lower stress on the skull. The force deforms the foam. This results in energy being dissipated (energy expended = force x distance) - that's what doesn't enter your brain (in theory)

.. and that is before we start with snag points and other design faults. Why not wear a helmet with instead on foam inside it has razer blades? Since you really won't want to fall off and bang your head, the inverse 'risk compensation' theory takes over and you will never crash. I really should patent this design before someone from cyclechat does.


The standard for helmets was the Snell B95, and 15 years ago, most helmets passed this

The modern helmet is simply not capable of meeting this standard. As a group we have allowed the cycle helmet's protection to decrease, swallowed the marketing claims (Kask's total security for instance) and like good little consumers paid an increasing sum for a less effective product.

Depends what you consider more important. Personally I think reducing the deceleration should be a priority (EN rules say <250 g, whereas Snell was 300g)

 

[martint235]

So the data and evidence to show how much of a 25mph impact is dissipated by a Kask helmet? Or are you just saying "physics" as a get out when it comes to evidence.? You don't need to have a human in the helmet to accurately simulate meaningful impacts (I don't believe any humans are harmed in the testing of motorcycle helmets for example). You cherry picked that testing vaccines is expensive but I believe a bottle of H&S is significantly less than a helmet but it's tested and evidenced.