Re: Speed and the fear of falling off

For all discussions about this "lively" subject. All topics that are substantially about helmet usage will be moved here.
Peter F
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Re: Speed and the fear of falling off

Postby Peter F » 5 Jun 2020, 11:40pm

Weight of average head is actually 5kg...
https://www.gwosteopathy.co.uk/much-head-weigh/

tim-b
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Re: Speed and the fear of falling off

Postby tim-b » 6 Jun 2020, 8:03am

Hi
How much of each energy type in them various transfers then? Showuz yer data.

You can work it out quite easily if you take a piece of string and cut it into lengths to represent the the variety of factors in any given collision scenario...
If you want a rule of thumb then it's less heat and noise than is generated by any kind of question about helmets :lol:
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tim-b
~~~~¯\(ツ)/¯~~~~

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Cugel
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Re: Speed and the fear of falling off

Postby Cugel » 7 Jun 2020, 8:16am

Peter F wrote:Thanks for derailing my post Cugel. I'm new to this forum so was unaware that my mere mention of my helmet would result in you steaming in and it getting moved.

For the record, it wasn't the plastic shell that was cracked, that was intact. It was the polystyrene at the back of the helmet that split in two, fully. It looked like it had been hit hard with a blunt object such as a road.

You weren't there and you didn't see the helmet so please stop trying to use this post to push your own agenda.

Thank you.


No crush then? Perhaps it was always cracked, from when it fell off the table in the cafe and you didn't notice? :-)

Cugel

Peter F
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Re: Speed and the fear of falling off

Postby Peter F » 7 Jun 2020, 10:18am

Cugel wrote:
Peter F wrote:Thanks for derailing my post Cugel. I'm new to this forum so was unaware that my mere mention of my helmet would result in you steaming in and it getting moved.

For the record, it wasn't the plastic shell that was cracked, that was intact. It was the polystyrene at the back of the helmet that split in two, fully. It looked like it had been hit hard with a blunt object such as a road.

You weren't there and you didn't see the helmet so please stop trying to use this post to push your own agenda.

Thank you.


No crush then? Perhaps it was always cracked, from when it fell off the table in the cafe and you didn't notice? :-)

Cugel


You're just a troll aren't you.

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Cugel
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Re: Speed and the fear of falling off

Postby Cugel » 7 Jun 2020, 11:36am

Peter F wrote:
Cugel wrote:
Peter F wrote:Thanks for derailing my post Cugel. I'm new to this forum so was unaware that my mere mention of my helmet would result in you steaming in and it getting moved.

For the record, it wasn't the plastic shell that was cracked, that was intact. It was the polystyrene at the back of the helmet that split in two, fully. It looked like it had been hit hard with a blunt object such as a road.

You weren't there and you didn't see the helmet so please stop trying to use this post to push your own agenda.

Thank you.


No crush then? Perhaps it was always cracked, from when it fell off the table in the cafe and you didn't notice? :-)

Cugel


You're just a troll aren't you.


No, just someone who disagrees with your inclination to award cycling helmets far more functionality in keeping you uninjured than they actually possess. It's always a poor response to assume being teased for offering unsubstantiated opinions is trolling. But perhaps you are a sensitive soul wanting only a safe space?

Cugel

PS That was just another tease so please don't feel abused.

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al_yrpal
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Re: Speed and the fear of falling off

Postby al_yrpal » 7 Jun 2020, 11:43am

Rather a cracked helmet than a cracked skull. Thats how helmets work they absorb impact but like climate change deniers a tiny minority disagree. Take no notice....

Al
Touring on a bicycle is a great way to explore and appreciate the countryside and towns you pass through. Make a difference...

RH20
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Re: Speed and the fear of falling off

Postby RH20 » 7 Jun 2020, 12:16pm

Why do people have such strong opinions about the advantage or otherwise of wearing a cycle helmet? Surely wearing a helmet is a personal choice. If I were to come off my bike I would rather have the bit of polystyrene between my head and the road than just my skin and bone. However, if someone else does not wear a helmet then that is their decision, both should be respected.

On a further note, a helmet is another place for fitting a cycle light. It may have been coincidence, but when I used to commute by bike and worked shifts, I noticed when riding in the dark, on approaching a traffic light that was at red, if I slowed and pointed the light on my helmet at the traffic light sensor, the light changed to green. But if I didn’t point at the sensor or slow down there would be the usual wait. This was always in the early hours of the morning when there was nothing else on the road.

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[XAP]Bob
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Re: Speed and the fear of falling off

Postby [XAP]Bob » 7 Jun 2020, 12:16pm

al_yrpal wrote:Rather a cracked helmet than a cracked skull. Thats how helmets work they absorb impact but like climate change deniers a tiny minority disagree. Take no notice....

Al



Helmets absorb energy by crushing, not by cracking.
If a helmet cracks then that shows very little, if it has crushed (even if it has cracked as well, the outer shell can hold it together) then that is the indication that it has absorbed energy.

Whether that energy absorption is useful or not is a ghetto discussion.
Whether that energy absorption is less likely to have been needed without the aforementioned garment is also a ghetto discussion.
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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[XAP]Bob
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Re: Speed and the fear of falling off

Postby [XAP]Bob » 7 Jun 2020, 12:19pm

RH20 wrote:Why do people have such strong opinions about the advantage or otherwise of wearing a cycle helmet? Surely wearing a helmet is a personal choice. If I were to come off my bike I would rather have the bit of polystyrene between my head and the road than just my skin and bone. However, if someone else does not wear a helmet then that is their decision, both should be respected.

Because the evidence base isn't there to suggest that they are of any benefit on a population level.
Various factors for that, but most likely the limited effectiveness, combined with risk homeostasis by both the wearer and those around the wearer.

However they are the *ONLY* thing which is ever discussed when cycle safety is concerned, and they are the last thing on the accepted list


On a further note, a helmet is another place for fitting a cycle light. It may have been coincidence, but when I used to commute by bike and worked shifts, I noticed when riding in the dark, on approaching a traffic light that was at red, if I slowed and pointed the light on my helmet at the traffic light sensor, the light changed to green. But if I didn’t point at the sensor or slow down there would be the usual wait. This was always in the early hours of the morning when there was nothing else on the road.

Don't fit a light to a helmet unless light and helmet are both certified in that condition. You really don't want the light catching and breaking your neck, or being punched through your skull.
There are various hats with lights built in, and therefore certified, although they are not generally "see with" lights.
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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al_yrpal
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Re: Speed and the fear of falling off

Postby al_yrpal » 7 Jun 2020, 12:27pm

[XAP]Bob wrote:
al_yrpal wrote:Rather a cracked helmet than a cracked skull. Thats how helmets work they absorb impact but like climate change deniers a tiny minority disagree. Take no notice....

Al



Helmets absorb energy by crushing, not by cracking.
If a helmet cracks then that shows very little, if it has crushed (even if it has cracked as well, the outer shell can hold it together) then that is the indication that it has absorbed energy.

Whether that energy absorption is useful or not is a ghetto discussion.
Whether that energy absorption is less likely to have been needed without the aforementioned garment is also a ghetto discussion.


Sorry that is incorrect. Have a read up on tne Izod test. I studied Mechanics and Strength of materials for 5 years and you are talking absolute... deformation absorbs energy and cracking or fracturing occurs when the impact is beyond the materials ability to deform. If you want all the energy to go into deforming or cracking your skull the answer is simple, dont wear a helmet.

Al
Touring on a bicycle is a great way to explore and appreciate the countryside and towns you pass through. Make a difference...

Peter F
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Re: Speed and the fear of falling off

Postby Peter F » 7 Jun 2020, 1:44pm

Cugel wrote:
No, just someone who disagrees with your inclination to award cycling helmets far more functionality in keeping you uninjured than they actually possess. It's always a poor response to assume being teased for offering unsubstantiated opinions is trolling. But perhaps you are a sensitive soul wanting only a safe space?

Cugel

PS That was just another tease so please don't feel abused.


I've met people like you on other forums. As a car enthusiast I used to frequent a forum called Piston Heads and there were a hardcore of members who disagreed with the idea of Global warming. Everytime it was half mentioned on any thread, or even the importance of low emissions, one particular member would pop up and derail the thread.

I don't care whether you think you know what happened, you weren't there so don't. I have a background in science and engineering so I'm happy I know whether or not my helmet provided me with protection that day or not, but thank you for your concern.

Just to add, I am impressed with the moderation on this forum. That was a clever way to deal with the situation.

Peter F
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Re: Speed and the fear of falling off

Postby Peter F » 7 Jun 2020, 1:57pm

Conveniently enough I found a picture of the helmet and there is indeed some crush damage. You can see the point of impact on the back of the helmet above where the split is visible and the polystyrene has been crushed and the outer shell has separated.
FB_IMG_1591534166903.jpg

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Cugel
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Re: Speed and the fear of falling off

Postby Cugel » 7 Jun 2020, 6:47pm

Peter F wrote:Conveniently enough I found a picture of the helmet and there is indeed some crush damage. You can see the point of impact on the back of the helmet above where the split is visible and the polystyrene has been crushed and the outer shell has separated.
FB_IMG_1591534166903.jpg


That's a picture of me sticking my tongue out at helmet fans! :-)

*****

Well, that helmet doesn't look like it took much of a blow to me. But without a device to measure the amount of force imparted to that broken bit at the time, we will never know.

I don't mind in the least if you want to wear a helmet; or if you tell yourself that it will increase your cycling safety or protection from head harm. Perhaps it will save you a headache if you fall off a lot on to your head (actually a rare event for most who fall - we hit out shoulders, hands, hips, knees and ankles). It's when you promote the notion of helmets offering lots of protection as a fact that I take issue with it, when all the evidence suggests that helmets are very poor at absorbing significant force and may induce the wearers to take more risks if they believe the helmet offers far more protection than it does.

It's a serious matter if helmet wearing actually does encourage some to take more risks and have a serious accident in which the helmet does nothing of any use.

Here's another anecdote in counterpoint to yours.

A local cycling club of new formation, lacking much in the way of deep knowledge of cycling, contained half a dozen Strava-strivers who weren't fit enough to get the usual kommy things so went for the downhill ones, of which there are a number around The Bowland Fells. Two of these fools - both avid helmet wearing MAMIl lads with all the gear and definitely no idea - had a go at the steeper side of Boundary (the drop from the 300M high top of The Trough of Bowland towards Sykes). It's steep with some difficult bends. It has drystone walls and deep rocky gullies to both sides.

These two were keen to regain their kom thing, which some local racing fellow apparently took by accident when out for a ride. They took silly risks on that dangerous descent and one got it wrong. Perhaps they thought that their £300 a piece helmets would save them if they came off? One did come off, as he lost control near the bottom doing about 35-40mph according to reports from his mate. He went down a 6 ft rocky stream bed and killed himself with a serious head injury.....

****
Of course this is just an anecdote. But it illustrates the danger of that belief that a helmet will provide far more protection than it actually does. Personally I believe they are actually dangerous to most users of them for this reason. People claiming they performed far more in giving protection than they did need to have their claim questioned as these "tales of the magic hat" give a false impression of their ability - and ability far greater than any claimed by the manufacturers themselves.

Cugel, probably just throwing mud from under a bridge.

tim-b
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Re: Speed and the fear of falling off

Postby tim-b » 7 Jun 2020, 7:37pm

Hi
A local cycling club of new formation, lacking much in the way of deep knowledge of cycling, contained half a dozen Strava-strivers who weren't fit enough to get the usual kommy things so went for the downhill ones, of which there are a number around The Bowland Fells. Two of these fools - both avid helmet wearing MAMIl lads with all the gear and definitely no idea - had a go at the steeper side of Boundary (the drop from the 300M high top of The Trough of Bowland towards Sykes). It's steep with some difficult bends. It has drystone walls and deep rocky gullies to both sides.
These two were keen to regain their kom thing, which some local racing fellow apparently took by accident when out for a ride. They took silly risks on that dangerous descent and one got it wrong. Perhaps they thought that their £300 a piece helmets would save them if they came off? One did come off, as he lost control near the bottom doing about 35-40mph according to reports from his mate. He went down a 6 ft rocky stream bed and killed himself with a serious head injury.....
****
Of course this is just an anecdote. But it illustrates the danger of that belief that a helmet will provide far more protection than it actually does. Personally I believe they are actually dangerous to most users of them for this reason. People claiming they performed far more in giving protection than they did need to have their claim questioned as these "tales of the magic hat" give a false impression of their ability - and ability far greater than any claimed by the manufacturers themselves.

Cugel, probably just throwing mud from under a bridge.

Lots of speculation that the family and friends possibly find disrespectful, with a few facts.

Helmetless TDF riders tragically killed on descents include Francisco Cepeda who crashed into a ravine in 1935, and Fabio Casartelli who collided with concrete blocks in 1995. Three examples that demonstrate nothing about attitude to risk.
In the case of Fabio Casartelli, "Michel Disteldorf, the French doctor who examined Casartelli's body on behalf of the coroner in Tarbes, where the rider was flown by helicopter after he crashed, told the Sunday Times that the point of impact was on the top of the skull, and that had Casartelli been wearing a hard helmet "some injuries could have been avoided"." https://en.wikipedia.org/wiki/Fabio_Casartelli

Regards
tim-b
~~~~¯\(ツ)/¯~~~~

Peter F
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Re: Speed and the fear of falling off

Postby Peter F » 7 Jun 2020, 7:54pm

Cugel wrote:
Peter F wrote:Conveniently enough I found a picture of the helmet and there is indeed some crush damage. You can see the point of impact on the back of the helmet above where the split is visible and the polystyrene has been crushed and the outer shell has separated.
FB_IMG_1591534166903.jpg


That's a picture of me sticking my tongue out at helmet fans! :-)

*****

Well, that helmet doesn't look like it took much of a blow to me. But without a device to measure the amount of force imparted to that broken bit at the time, we will never know.

I don't mind in the least if you want to wear a helmet; or if you tell yourself that it will increase your cycling safety or protection from head harm. Perhaps it will save you a headache if you fall off a lot on to your head (actually a rare event for most who fall - we hit out shoulders, hands, hips, knees and ankles). It's when you promote the notion of helmets offering lots of protection as a fact that I take issue with it, when all the evidence suggests that helmets are very poor at absorbing significant force and may induce the wearers to take more risks if they believe the helmet offers far more protection than it does.

It's a serious matter if helmet wearing actually does encourage some to take more risks and have a serious accident in which the helmet does nothing of any use.

Here's another anecdote in counterpoint to yours.

A local cycling club of new formation, lacking much in the way of deep knowledge of cycling, contained half a dozen Strava-strivers who weren't fit enough to get the usual kommy things so went for the downhill ones, of which there are a number around The Bowland Fells. Two of these fools - both avid helmet wearing MAMIl lads with all the gear and definitely no idea - had a go at the steeper side of Boundary (the drop from the 300M high top of The Trough of Bowland towards Sykes). It's steep with some difficult bends. It has drystone walls and deep rocky gullies to both sides.

These two were keen to regain their kom thing, which some local racing fellow apparently took by accident when out for a ride. They took silly risks on that dangerous descent and one got it wrong. Perhaps they thought that their £300 a piece helmets would save them if they came off? One did come off, as he lost control near the bottom doing about 35-40mph according to reports from his mate. He went down a 6 ft rocky stream bed and killed himself with a serious head injury.....

****
Of course this is just an anecdote. But it illustrates the danger of that belief that a helmet will provide far more protection than it actually does. Personally I believe they are actually dangerous to most users of them for this reason. People claiming they performed far more in giving protection than they did need to have their claim questioned as these "tales of the magic hat" give a false impression of their ability - and ability far greater than any claimed by the manufacturers themselves.

Cugel, probably just throwing mud from under a bridge.


Two points,
1. the helmet did take quite am impact
2. No one in their right mind thinks a helmet will save them from an off at 40mph. Your anecdote is akin to saying wearing a seatbelt didn't save someone from driving into a wall at 100mph. Utterly irrelevant. The same people would have taken insane risks helmet or not.