"Denialism" and cycle helmets

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Re: "Denialism" and cycle helmets

Postby Vorpal » 8 Aug 2018, 7:49am

Cunobelin wrote:
I don't think that is a very good analogy.

If we accept for the sake of argument that helmets have some capability to absorb energy, and reduce an injury, then they will absorb energy, up to their maximum capability whether the impact speed is 12 mph or 20 mph. It's just that a a 20 mph impact is more likely to exceed the energy absorption capability. That doesn't make it pointless to wear.

It also ignores that people might have other reasons to wear a helmet. The principle reason in my case is that I sometimes enter events that require them. If I want to do an event, I typically protest (once) helmet rules, just to make my point, then take my helmet along, and ride the event anyway. Why? Because I want to participate, and my not doing so out of protest will not be noticed by anyone, or contribute to any cultural changes.



It is because it is simple and factual.

If you were to use a set of brakes limited to 20 mph to stop from 60 mph then there would be a real danger and in reality an explanation that they may not function

If the brakes failed and you had an accident because you failed to stop, you would be seen as negligent or reckless in your actions.

Yet none of this simple visit to reality doesn't apply to helmets?

It may be simple and factual, but in physics/engineering terms it is not very realistic.

Even with the brakes example, depending on the system, it is likely that they would slow the vehicle you were trying to stop, even if they were not capable of stopping it (before anyone starts in with examples, yes I know that there are brake systems that would effectively not be able to do anything).

With helmets, I can imagine that some designs are likely to fail without absorbing much energy. However, they are basically designed to absorb energy. And in most circumstances that's what they will do, even when the test parameters (which aren't necessarily the design parameters) are exceeded.

It is probaly the case that if a cyclist hits their head in a crash with a car at an effective speed of 60 mph, there is little point in the helmet being there, because the design parameters have been exceeded by so much that it's miniscule by comparison. Using the brakes analogy, it would be like trying to stop a car with bicycle rim brakes.

But a fall or crash at 20 mph? There is plenty of evidence that (the majority) of helmets have some capability to absorb energy that would otherwise cause or contribute to a head injury.
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Re: "Denialism" and cycle helmets

Postby [XAP]Bob » 8 Aug 2018, 8:48am

Pjclinch & Vorpal...

I agree that there are other factors in play wrt efficacy, thats why I said *could* be pointless.

The thing is that in all the pictures of helmets that have ‘saved a life’, it is very rare to see one that has functioned as designed (that is through plastic deformation rather than simple brittle fracture).
Combined with the empirical evidence, which suggests narrowberror bars around zero effectiveness, I am forced to conclude that they don’t provide significant protection in real world incidents.
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Re: "Denialism" and cycle helmets

Postby Cunobelin » 8 Aug 2018, 9:19am

Vorpal wrote:
Cunobelin wrote:
I don't think that is a very good analogy.

If we accept for the sake of argument that helmets have some capability to absorb energy, and reduce an injury, then they will absorb energy, up to their maximum capability whether the impact speed is 12 mph or 20 mph. It's just that a a 20 mph impact is more likely to exceed the energy absorption capability. That doesn't make it pointless to wear.

It also ignores that people might have other reasons to wear a helmet. The principle reason in my case is that I sometimes enter events that require them. If I want to do an event, I typically protest (once) helmet rules, just to make my point, then take my helmet along, and ride the event anyway. Why? Because I want to participate, and my not doing so out of protest will not be noticed by anyone, or contribute to any cultural changes.



It is because it is simple and factual.

If you were to use a set of brakes limited to 20 mph to stop from 60 mph then there would be a real danger and in reality an explanation that they may not function

If the brakes failed and you had an accident because you failed to stop, you would be seen as negligent or reckless in your actions.

Yet none of this simple visit to reality doesn't apply to helmets?

It may be simple and factual, but in physics/engineering terms it is not very realistic.

Even with the brakes example, depending on the system, it is likely that they would slow the vehicle you were trying to stop, even if they were not capable of stopping it (before anyone starts in with examples, yes I know that there are brake systems that would effectively not be able to do anything).

With helmets, I can imagine that some designs are likely to fail without absorbing much energy. However, they are basically designed to absorb energy. And in most circumstances that's what they will do, even when the test parameters (which aren't necessarily the design parameters) are exceeded.

It is probaly the case that if a cyclist hits their head in a crash with a car at an effective speed of 60 mph, there is little point in the helmet being there, because the design parameters have been exceeded by so much that it's miniscule by comparison. Using the brakes analogy, it would be like trying to stop a car with bicycle rim brakes.

But a fall or crash at 20 mph? There is plenty of evidence that (the majority) of helmets have some capability to absorb energy that would otherwise cause or contribute to a head injury.


I am glad that you have accepted the point that there is some doubt as to the wisdom of using equipment outside the design parameters

I also like the fact that you now wish too limit "fast rides" to 20 mph. Many cyclists will be exceeding that by a fair margin, professionals for instance, with the average speed of Le Tour being 35 mph overall, and the slowest recorded completion (1919_ at 25 mph overall average

The downhill speeds can be in excess of 80 mph

Yet these riders are being"protected" by an item untested above 12 mph!

Hardly common sense?

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Re: "Denialism" and cycle helmets

Postby Nigel » 8 Aug 2018, 11:06am

Cunobelin wrote:
I also like the fact that you now wish too limit "fast rides" to 20 mph. Many cyclists will be exceeding that by a fair margin, professionals for instance, with the average speed of Le Tour being 35 mph overall, and the slowest recorded completion (1919_ at 25 mph overall average

The downhill speeds can be in excess of 80 mph


I think you have km and miles muddled up.
Tour de France averages are typically 35-42kph for the entire tour. 35mph for a stage has been seen only in a team time trial, never in an individual stage.
Downhill is more complex. Sustained speeds of over 80km/hr downhill (50mph) are regularly seen on the Tour de France. Peaks just touching 80mph (130kph) have been recorded, but are pretty rare.

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Re: "Denialism" and cycle helmets

Postby Cunobelin » 8 Aug 2018, 11:46am

Nigel wrote:
Cunobelin wrote:
I also like the fact that you now wish too limit "fast rides" to 20 mph. Many cyclists will be exceeding that by a fair margin, professionals for instance, with the average speed of Le Tour being 35 mph overall, and the slowest recorded completion (1919_ at 25 mph overall average

The downhill speeds can be in excess of 80 mph


I think you have km and miles muddled up.
Tour de France averages are typically 35-42kph for the entire tour. 35mph for a stage has been seen only in a team time trial, never in an individual stage.
Downhill is more complex. Sustained speeds of over 80km/hr downhill (50mph) are regularly seen on the Tour de France. Peaks just touching 80mph (130kph) have been recorded, but are pretty rare.


They are estimates, apart from the (slowest) that I had to Google.

They still remain well above the design parameters of the helmets that they are forced to wear

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Re: "Denialism" and cycle helmets

Postby Brucey » 8 Aug 2018, 11:54am

only if you are planning on head butting a brick wall at that speed. If you fall in various other ways, the helmet works as intended, because the vertical component of velocity is within the range for which the helmet was designed.

Helmets have been compulsory in UK amateur road racing for many decades. The only change in recent times has been the nature of the helmet, and that pros are required to use them in all UCI events.

cheers
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Re: "Denialism" and cycle helmets

Postby Vorpal » 8 Aug 2018, 12:10pm

Cunobelin wrote:I also like the fact that you now wish too limit "fast rides" to 20 mph. Many cyclists will be exceeding that by a fair margin, professionals for instance, with the average speed of Le Tour being 35 mph overall, and the slowest recorded completion (1919_ at 25 mph overall average

The downhill speeds can be in excess of 80 mph

Yet these riders are being"protected" by an item untested above 12 mph!

Hardly common sense?

I'm an engineer. I am an engineer wqith a specialty in safety & reliability. I see examples everyday of stuff used outside it's design envelope, sometimes to the detriment of the user.

I haven't limited 'too fast' to 20 mph, any more than you have limited it to 40 mph. It was an example.

It's not a hard fast line. It's silly to say that an item or a system is useless outside it's design parameters becasue that is untrue in most circumstances. A bicycle helmet is less useful in a crash at 60 mph than it is at 20 mph. That doesn't make it useless in either circumstance. It depends upon the helmet design and the circumstances of the crash. It can be demonstrated in some specific circumstances that a helmet makes no more than a negligible contribution to the outcome. I am not going to dispute that. Only that that isn't always the case when the design parameteres are exceeded.

Would you take a bike to the tip because it has exceeded it's design life of 6 years? Obviously not. Would you take it when it's 12 years old? What about an original handbuilt Holdsworth?

Would I offer any guarantees for a bicycle helmet beyond test circumstances? Absolutely not. But I don't have to, and I'm not trying to.

There are so many other problem with the helmet issue, it seems silly to argue this single point, but I think that you'd be hard pressed to find an engineer who would accept the argument that a helmet has no protective capability outside of it's design parameters.

[XAP]Bob wrote:Pjclinch & Vorpal...

I agree that there are other factors in play wrt efficacy, thats why I said *could* be pointless.

The thing is that in all the pictures of helmets that have ‘saved a life’, it is very rare to see one that has functioned as designed (that is through plastic deformation rather than simple brittle fracture).
Combined with the empirical evidence, which suggests narrowberror bars around zero effectiveness, I am forced to conclude that they don’t provide significant protection in real world incidents.


The pictures posted on social media are a small part of the picture. It seems clear to me that helmets do provide some protection in the event of crash, and Rune Elvik who is oft quoted on here, has come to the same conclusion. This limited benefit is offset by many other factors, some of which probably have not even been identified. I think that the circumstances in which a helmet has any influence at all are a very small number, and those in which a bicycle helmet has ever offered significant protection to a cyclist in the UK can probably be counted on one hand. None of them, or almost none apply to the circumstances a typical utulity cyclist will encounter. That is my best estimation based upon my knowledge and experience and reading the multitudes of studies and reports discussed on here.

No one should wear a helmet on the basis that it will save their life. Because it simply won't do that.

My reasons for not wearing a helmet have nothing to do with the potential for them to protect my skull, because I just don't think that the benefit is significant enough to make it an important factor in my decision making process.
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Re: "Denialism" and cycle helmets

Postby [XAP]Bob » 8 Aug 2018, 1:32pm

Vorpal wrote:
[XAP]Bob wrote:Pjclinch & Vorpal...

I agree that there are other factors in play wrt efficacy, thats why I said *could* be pointless.

The thing is that in all the pictures of helmets that have ‘saved a life’, it is very rare to see one that has functioned as designed (that is through plastic deformation rather than simple brittle fracture).
Combined with the empirical evidence, which suggests narrowberror bars around zero effectiveness, I am forced to conclude that they don’t provide significant protection in real world incidents.


The pictures posted on social media are a small part of the picture. It seems clear to me that helmets do provide some protection in the event of crash, and Rune Elvik who is oft quoted on here, has come to the same conclusion. This limited benefit is offset by many other factors, some of which probably have not even been identified. I think that the circumstances in which a helmet has any influence at all are a very small number, and those in which a bicycle helmet has ever offered significant protection to a cyclist in the UK can probably be counted on one hand. None of them, or almost none apply to the circumstances a typical utulity cyclist will encounter. That is my best estimation based upon my knowledge and experience and reading the multitudes of studies and reports discussed on here.

No one should wear a helmet on the basis that it will save their life. Because it simply won't do that.

My reasons for not wearing a helmet have nothing to do with the potential for them to protect my skull, because I just don't think that the benefit is significant enough to make it an important factor in my decision making process.


Pretty much agree with you. The limited protection they provide is likely to be mostly dealing with abrasions/lacerations rather than anything genuinely lifesaving - there is also the risk that the rotational effects of cycle helmets are untested, and we do know that rotational acceleration is one of, if not *the* leading cause of TBI.


Although the social media pictures are only a small part of the picture, they are a large part of what tells the public that they are an essential piece of safety equipment...
I'd love to see some actual (independent, but rigorous, analysis of helmets involved in crashes - but I doubt that will happen any time soon.
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.

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Re: "Denialism" and cycle helmets

Postby Cunobelin » 8 Aug 2018, 3:34pm

Brucey wrote:only if you are planning on head butting a brick wall at that speed. If you fall in various other ways, the helmet works as intended, because the vertical component of velocity is within the range for which the helmet was designed.

Helmets have been compulsory in UK amateur road racing for many decades. The only change in recent times has been the nature of the helmet, and that pros are required to use them in all UCI events.

cheers



That old favourite.......The Melon test

There is also proof that wearing a Melon (or other hard shell fruit) also reduces head injury when butting a wall

Anyone for compulsory Melons?


Image

As for the "compulsion" of helmets in events... this is yet another example of the naivety and stupidity of these blind advocates of helmet use and the absolute lack of any intelligent input into the compulsion

UK Cycling Events is a major organiser and for several years they insisted that helmets had to comply the "latest ANSI or Snell requirements". This comprehensively excluded most helmets for sale in the UK as many EN 1078 helmets that did not meet these requirements!

Unless they had additional verification they were banned... however the organisation was quite happy to ignore their own rules and blindly accept any helmet

At least after some time they were educated about this and changed their requirements to include EN1078 and now require You must wear a safety-approved cycling helmet complying with latest EN1078, ANSI Z90/4 or SNELL standards during your participation in the event. Any rider not wearing a helmet will not be covered by the event insurance and will be disqualified from the event and could be liable for damages if involved in an accident on that basis. You must accept this as a condition of entry.

What a shame they are showing such gross lack of knowledge.....

This is a helmet that passes ANSI Z90/4:


Image

The ANSI committee has not met since 1995, and the last correspondence at all was in 2003 that's right - 2003!!!!


In an article posted on their Web site on July 16th, 2003, ANSI acknowledged publicly for the first time that their bicycle helmet standards are now the ASTM bike helmet standards, referring to them as ANSI/ASTM standards.
The old ANSI standard with its less-stringent testing had been withdrawn by ANSI, leaving many US state and local helmet laws still specifying that standard and therefore perhaps weakening them. This acknowlegment of a joint standard may eliminate that problem. The current ASTM standard is equivalent to the CPSC bicycle helmet standard, so meeting "the ANSI standard" now means meeting the ASTM and CPSC standards as well.


So this organisation is insisting on meeting a standard set by a committee that hasn't actually met for over 23 years, and was officially withdrawn 15 years ago as they recognised that it was not fit for purpose!

The ignorance is absolutely stunning.........

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Re: "Denialism" and cycle helmets

Postby pjclinch » 8 Aug 2018, 5:55pm

Cunobelin wrote:
Brucey wrote:only if you are planning on head butting a brick wall at that speed. If you fall in various other ways, the helmet works as intended, because the vertical component of velocity is within the range for which the helmet was designed.

Helmets have been compulsory in UK amateur road racing for many decades. The only change in recent times has been the nature of the helmet, and that pros are required to use them in all UCI events.

cheers



That old favourite.......The Melon test

There is also proof that wearing a Melon (or other hard shell fruit) also reduces head injury when butting a wall

Anyone for compulsory Melons?


Brucey isn't talking about protection from head-butting walls, he's making the same point I've already tried to get across a couple of times. That point, again, is that the 12 mph figure is the vertical component of the velocity, entirely provided by gravity, and that is what will break your skull (or not) on a fall to the road, because while the road will stop you dead in the vertical you'll slide and/or roll in the horizontal, and that's not the bone breaker.
Walls come in to it as an exception: if you hit a wall at a horizontal 50 mph the game is pretty much up, because that'll take away all that 50mph's worth of KE pretty much instantaneously. But hitting walls is, I would suggest, the exception rather than the rule. I think Brucey was suggesting that too.

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Re: "Denialism" and cycle helmets

Postby Cunobelin » 8 Aug 2018, 6:35pm

pjclinch wrote:
Cunobelin wrote:
Brucey wrote:only if you are planning on head butting a brick wall at that speed. If you fall in various other ways, the helmet works as intended, because the vertical component of velocity is within the range for which the helmet was designed.

Helmets have been compulsory in UK amateur road racing for many decades. The only change in recent times has been the nature of the helmet, and that pros are required to use them in all UCI events.

cheers



That old favourite.......The Melon test

There is also proof that wearing a Melon (or other hard shell fruit) also reduces head injury when butting a wall

Anyone for compulsory Melons?


Brucey isn't talking about protection from head-butting walls, he's making the same point I've already tried to get across a couple of times. That point, again, is that the 12 mph figure is the vertical component of the velocity, entirely provided by gravity, and that is what will break your skull (or not) on a fall to the road, because while the road will stop you dead in the vertical you'll slide and/or roll in the horizontal, and that's not the bone breaker.
Walls come in to it as an exception: if you hit a wall at a horizontal 50 mph the game is pretty much up, because that'll take away all that 50mph's worth of KE pretty much instantaneously. But hitting walls is, I would suggest, the exception rather than the rule. I think Brucey was suggesting that too.

Pete.



Except for the poor design of present helmets that have sharp edges and planes referred to as "Snag Points" These present obstructions that preventive sliding and in some cases can even cause the helmet to eject.

I believe that during testing this is avoided by taping the helmets isn place with heavy duty tape........ which hurts when you remove not, especially if you have a beard or long hair

There is also the issue as to whether there is a "clean" vertical component as in real life there will be kerbs, vehicles, and a myriad of other obstructions in the road

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Re: "Denialism" and cycle helmets

Postby pjclinch » 8 Aug 2018, 8:18pm

Cunobelin wrote:Except for the poor design of present helmets that have sharp edges and planes referred to as "Snag Points" These present obstructions that preventive sliding and in some cases can even cause the helmet to eject.

I believe that during testing this is avoided by taping the helmets isn place with heavy duty tape........ which hurts when you remove not, especially if you have a beard or long hair

There is also the issue as to whether there is a "clean" vertical component as in real life there will be kerbs, vehicles, and a myriad of other obstructions in the road


While these are all real concerns they aren't always going to be issues. They limit the possibilities of a helmet's value but that is not the same thing at all as saying "you're over 12 mph so clearly a helmet won't help you". Citing the design speed and suggesting that bikes often go faster is a dud argument and the above exceptions are on the lines of if it's not perfect it's no use at all, and that's a dud argument too.

Here's Nairo Quintana crashing. I think speeds of over 12 mph would have been involved...

If you go over the bars and do a forward roll like that would you rather have a pad between your cranium and the road, or would you assume it was obviously useless because of the speed? Note how far he travelled after leaving the saddle, and note that for almost the whole of the crash his head is nowhere near the road. He'd almost certainly have been okay without the lid, but quite possibly less able to get back on and finish without losing much time (which he did).

In summary, if you want to bring up genuine concerns over helmet design and specification I'm right with you (I have been assured many times I'm an "anti-helmet zealot", after all!), but if we're going to shoot down poor reasoning then it really has to be with good reasoning. Suggesting exceeding 12 mph on your bike renders a helmet superfluous is shocking reasoning.

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Re: "Denialism" and cycle helmets

Postby [XAP]Bob » 8 Aug 2018, 10:31pm

pjclinch wrote:In summary, if you want to bring up genuine concerns over helmet design and specification I'm right with you (I have been assured many times I'm an "anti-helmet zealot", after all!), but if we're going to shoot down poor reasoning then it really has to be with good reasoning. Suggesting exceeding 12 mph on your bike renders a helmet superfluous is shocking reasoning.


But it is interesting how many people have no idea what the design criteria are, actually it's interesting how many have no interest either.

That alone makes it worth mentioning...
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.

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Re: "Denialism" and cycle helmets

Postby Cunobelin » 9 Aug 2018, 7:27am

[XAP]Bob wrote:
pjclinch wrote:In summary, if you want to bring up genuine concerns over helmet design and specification I'm right with you (I have been assured many times I'm an "anti-helmet zealot", after all!), but if we're going to shoot down poor reasoning then it really has to be with good reasoning. Suggesting exceeding 12 mph on your bike renders a helmet superfluous is shocking reasoning.


But it is interesting how many people have no idea what the design criteria are, actually it's interesting how many have no interest either.

That alone makes it worth mentioning...



The question still remains, common sense says that if you are using "safety equipment" then it should be used within the proven design limits

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Re: "Denialism" and cycle helmets

Postby Vorpal » 9 Aug 2018, 7:41am

Cunobelin wrote:The question still remains, common sense says that if you are using "safety equipment" then it should be used within the proven design limits

Hard hats worn on construction sites occasionally encounter forces that exceed their proven design limits, such as dropped objects that are large enough, or have been dropped from high enough to exceed legislated standards.

Therefore they are pointless?

Similarly wearing leathers or helmets on motorcycles?

The frame of a car? The roll cage of a racing car? The roll over protective structure on a tractor?

All of these are safety systems which sometimes have their design parameters exceeded.

Does that make them useless? Should we tell race car drivers that they must never exceed a particular speed (100 mph?) because that increases the risk they will have an accident which exceeds the capability of the roll cage to protect them? Or a tractor operator that they must never operate on hills?
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