Why cycle helmets are dangerous

[MarkF]

I don't get why you wouldn't want to stick one on your kids head when they are learning to ride a bike,

There is a large grassy slope opposite my house, that's why. Having said that helmets didn't exist when I was their (learning) age and I know nobody who suffered a head injury. But, if I lived in a surburban estate without access to a nearby grassy slope, yes, I'd take advantage of the small protection they offer knowing that the child would likely often fall off. The inherent/acceptable risk then changes.


The below was is one of several, "I haven't read the thread but I can't resist chipping in about something I know less than nothing about" posts. Seat belts and motorcycle helmets, the difference? Easy to prove a nett benefit, not much of a safety debate to be had, a liberty one maybe and I read recently that the USA had repealed the compulsory motorbike helmet law in some states.

I don't get why you wouldn't put up with wearing one while your with said kid, I also don't really see much point in not wearing one anyway but then I honestly don't give a shit if anyone doesn't wear one, but I also think that if your going to be riding on the roads you should be made to wear one and you should be made to stick to the laws of the road but that's another point.

The same people who bitch and moan about having to wear one are probably the same types of people who bitched about being made to wear seat belts, do it or don't do it its up to you BUT if you come off and end up a vegetable its on you.

I don't ride, I don't see the point I have a car, but in the last few months I know of about 3 accidents (off road) one wasn't wearing a helmet and he got his head all scraped up, wouldn't have happened with the helmet he admits that and when he came off again a few weeks later he was happy to have it, 3rd one guy was in a bad way helmet probably didn't hurt the situation but he was out for a while and a broke a bone or two but don't know him well enough to tell you how it happened.

[kungfugerbil]

Having said that helmets didn't exist when I was their (learning) age and I know nobody who suffered a head injury

You must realise that's as statistically complete as those who give first or second hand stories of injuries but they were dismissed. There could have been a hundred children killed a week on bikes but you wouldn't have known any of them in a country of 15 million children. There weren't of course, and that's a very good thing.

The point is that you're gambling - you've said yourself you're weighing up the odds. You of course do things to increase the odds in your favour (teaching good road craft, keeping their bikes maintained well etc).

The issue for me is personally is that the consequences can be so catastrophic that it's worth doing what you can to mitigate the effects if it does occur. I still do the things you do, but stick a lid on their bonce too.

The likelihood of eight lift cables snapping is very low but there is still an additional safety brake as the consequences are so catastrophic - it's the same deal for me.

[MarkF]

The point is that you're gambling - you've said yourself you're weighing up the odds. You of course do things to increase the odds in your favour (teaching good road craft, keeping their bikes maintained well etc).

The issue for me is personally is that the consequences can be so catastrophic that it's worth doing what you can to mitigate the effects if it does occur. I still do the things you do, but stick a lid on their bonce too.

The likelihood of eight lift cables snapping is very low but there is still an additional safety brake as the consequences are so catastrophic - it's the same deal for me.

Not disagreeing but as I have posted earlier along with 2 links, the chances of injury are remarkably and surprisingly similar for walking and cycling. No helmet wearer has yet explained why they don't wear one whilst out walking or given the their arbitrary cut off point for helmet wearing and the reason for it. We have though, seen some say they ride faster than the helmets were designed for and others say they wear them only sometimes..............

[Josh B]

I wear a helmet. Sometimes. Most of the time, really. Especially when its wet - as it's the low speed slips that its most likely to help with.

As to being a pedestrian, again you appear to be confusing statistical analysis for the population as a whole with personal risk analysis.

In my own life I cannot see how a helmet as a pedestrian could ever be relevant to me.

As a cyclist I do see how if might be and wear a helmet accordingly. Simples.

As to speed, I don't kid myself a helmet will magically make me invulnerable and there are other risks involved. I mitigate them as well as I can and thats as much as I can do.

It's neither complicated not contradictory.

[deryckb]

Not disagreeing but as I have posted earlier along with 2 links, the chances of injury are remarkably and surprisingly similar for walking and cycling. No helmet wearer has yet explained why they don't wear one whilst out walking or given the their arbitrary cut off point for helmet wearing and the reason for it. We have though, seen some say they ride faster than the helmets were designed for and others say they wear them only sometimes..............

Don't forget drinking helmets, running helmets and OAP helmets. The last one is especially needed as they seem to go down with remarkable regularity :)

[kungfugerbil]

No helmet wearer has yet explained why they don't wear one whilst out walking

I said so earlier; If my walk took me through the centre of two or more lanes of cars moving at 30mph upwards, round roundabouts or across T junctions then I would.

Serious pedestrian accidents happen in one place and one place only - where you cross roads. If you eliminate or minimise the risks there, then there is no reason to wear any protective gear. Cyclists on the other hand face danger from passing vehicles, turning vehicles, vehicles at junctions, vehicles at roundabouts, other cyclists, pedestrians, slippery manhole covers, poorly maintained roads, missing or incorrectly replaced drain covers and just plain falling off.

[chrisparker]

No helmet wearer has yet explained why they don't wear one whilst out walking or given the their arbitrary cut off point for helmet wearing and the reason for it.

Ok, I'll try.

I cycle most days, and walk every day.

In my 30+ years of walking I've never had a car run in to me, whether I'm on the pavement, office, house, corridor etc. Mostly, the risks from walking are from personal error, not looking where one is going. And most who fall when walking stumble and automatically put their arms out in front to break a fall.

We're pre-programmed to protect our head.

Runners, tend to avoid collisions with cars too, and fall in the same manor as pedestrians. They also run facing the traffic when on the road so if a car gives no space they can run up the verge before impact.

I would expect most cyclists injuries are caused by other traffic.
Cyclists only realise a car has come to close from behind when it's too late to react. Also putting arms out to break a fall is useless, the bike's in the way and we mostly fall side ways.

A couple of times mountain biking I've fallen head first over the bars. Never happened when walking.

Over 15 years commuting I've been knocked off three times and had countless near misses. No serious injuries and I usually wear a regular helmet.

Mountain biking, I'd crash or fall off almost every week (mostly jumps / down hill) and wore a full face helmet.

Local riding, round the village or to the park / shop I don't wear a helmet. I find roads are quieter, slower and drivers more alert when not in rush hour.

I don't always wear a helmet, and wouldn't want it to become law. It's a personal decision and should remain so.

[Argee1977]

Haven't read all the way through, but I'm a pretty avid cyclist, and always wear a helmet. The main reason is that in cycling there's a lot of chances that if you come off your bike, then you'll smack your head on the ground, especially if it's a sideways slip or coming off on ice or slippery surfaces. I've had a fair few smacks, had concussion a few times and wouldn't want to guess at what the outcomes would have been without a helmet.

I also had a mate who came off his bike whilst nipping down the shops, he hit his head on the kerb and died from the injuries sustained, so having known something like that it makes you think about those daft little accidents that tend to have the worst outcomes.

As for linking walking to cycling, they're two completely different activities, when I fall whilst walking I put my hands out and protect my head, in most instances you know a fall is coming so have time, you are also falling at slower speeds and not having as high of a risk of a head impact as with cycling.

[Huertecilla]

According to their website the airbag uses a helium cold gas inflator which doesn't sound like rocket fuel.

I stand corrected; the gas source is a liquid (pressure) conrainer, not a solid.
The inflation is still explosive and the gas displácing air.
All negatives apply undeminished.

Still a VERY wellcome alternative. Hope they can get is homologated.

[mrpgkennedy]

Chrisboard mans says....

Chris boardman is an ex professional cyclist, he has cycled a lot

I've flown an obscene amount, no matter how many hours i spend flying, i do not know how to fly a plane, design a plane

I don;t know if there is anyway to check, but i'm pretty sure he's never been called as an expert witness on cycle safety, sorry but his opinion is no more important than the man in the pub, we have the celebrity obsessed culture that somehow because you're famous for one things your opinion on something else is more valuable then anybody else ( sting with his private jet to complain about climate change, bono who wants governments to give more money to the poor in Africa, yet moves his company around so he has to pay as little corporation tax as possible). Chris Boardman clearly doesn't like wearing a helmet, that's fine, but he shouldn't be allowed just to use his fame to change peoples opinion anymore then lewis hamilton should be given a spanner and an angle grinder and told to feel free to make any changes you need to the car

statistics are really dangerous when not used correctly, 9 out of 10 of the participants in gang rape enjoy the experience

The first test for anything like this is fundamentally does it sound right and plausible based on your own experiences, from your day to day life, from walking and cycling, which one feels like you are more likely to be injured doing it, does it sound right that you are as likely to get a head injury walking as cycling?

The statistics are based on the number of pedestrian deaths vs the number of cyclists deaths per year and the number is similar

so walking is as dangerous as cycling, you don't need helmets for walking, therefore you don't need them for cycling

or to put it another way, more people die from bee stings then from shark attacks, so there is no reason when in the sea to pay a shark any more attention then you would a bee, or if you go near a beehive only do it in a bee cage and have a whole load of people placed around other peoples house to warn them of when there may be a bee in the area

Firstly the number of deaths is from road traffic collisions ( we're not meant to call them road traffic accidents any more) i.e. it takes two things to collide, or was we like to say vs, i.e. car vs pedestrian, cyclist vs lorry, car vs tree, so there are as many deaths from pedestrians colliding with other vehicles as there are cyclists.

The problem is there are many more pedestrians then cyclists, have a look down any street and you see far more pedestrians at one time then cyclists, not only that ( yes i know there are exceptions) but pedestrians are only collide when they enter the same environment as the other vehicles (i.e. the road) so it's not waling that's dangerous, it;s crossing the road. Yes crossing the road is dangerous, it's why we have the green cross code, it's why we have various pedestrian crossings, but people don't always use them and they get hit. The danger is when the road is crossed, think how may times a day you cross the road, this is far higher then even for a keen cyclist then the number of bike rides

There are many less cyclists, yes they die as frequently as the much more numerous road crossing people, they also are not separated from the other object is the vs collision like pedestrians, so the risk is higher and continually higher

Hence the number of events are of a completely different magnitude to cause the same number of deaths

Also pedestrians if they fall without being hit put their hands out to save themselves, we have generally evolved not to die from our main method of propulsion. The next bit is anecdotal based on my practice, but pedestrians when hit tend to suffer more body and less head trauma then cyclists. This is no less fatal, but it much harder to prevent, it;s because the point of contact tends to be the lower limb and pelvis first, followed by the chest abdomen and finally head.

Cyclists when they fall off are travelling faster, don;t have free hands to have the reaction speed to put their gads out to save themselves so the head hit earlier ( weird they behaviour much closer to old people in this respect, who do get loads of head injuries). Further more when anyone is hot there tends to be two collisions, the first with the other vehicle the second with the ground, the second one all things being equal is clearly going to be worse for the cyclist, unable to respond with their one speed.

When it comes to cyclist/pedestrian versus stationary object, it's pretty easy to see who going to loose just doe to momentum and having free hands

Given enough time i'm sure cyclists will evolve with thicker skulls, thicker skin, more csf, more compartments in the skull to resist movement, feet that lock into pedals, spare limbs to cushion their fall and maybe be cured of their red/green colour blindness ( sorry i could't resist)

Sorry Chris Boardman is an idiot, he should stick to what is his good at, being good at cycling in the past, i wish his celebrity ilk were held accountable for their opinions, and unless they are an expert say thing like, i think.... not just come out as if it's fact

I assume next we'll all be taking Wayne Rooneys advice about what need to be done for England to win the world cup, he's famous so he must know :(

oh just a quick ps, the pedestrian figures are also skewed by alcohol

[Huertecilla]

Chrisboard mans says....

I assume next we'll all be taking Wayne Rooneys advice about what need to be done for England to win the world cup, he's famous so he must know :(

oh just a quick ps, the pedestrian figures are also skewed by alcohol

I have raced everything on two wheel for decades, motorised and pedaled, also cross country horse riding unbridled. Taken tumbles as a matter of course.

It is an idividual risk assessment based on chance x consequences.
Due to the infinite variations there is no simgle outcome including a wide varied necessity in level of protection offered by the helmet (and other gear).
The resultant can be as low as for walking or as high as racing a moto-gp bike. We should be able to decide accordingly.

I have been excluded from a cross terrain horse race once because my full face gear was higher specced than the rule-book listed. I refused the lesser spec open faced cap yet I also ride with just a felt hat is the risk is as low as strolling along.

We should not be obliged to wear the cycling helmets which offer very little protection and lull us into a false sense of security.
It is great that they are availabel and great that many decide to use them, bád that they have no clue that the thing offers little to no side impact protection and is NOT designed to cope with impacts involving cars

[Josh B]

Cilla, while you sound like an interesting chap with a great joie de vivre, you have an awfully low estimation of your fellow man. Its a bit of a recurring theme with your threads: "i am smarter than the rest." Its this that irritates me and a number of others -arrogance is not an endearing trait.

Most people are not lulled into a false sense of security or think helmets can do things they cant. We are not all idiots you know! And for that reason i agree with freedom of choice.

[Huertecilla]

Cilla, while you sound like an interesting chap with a great joie de vivre, you have an awfully low estimation of your fellow man. Its a bit of a recurring theme with your threads: "i am smarter than the rest." Its this that irritates me and a number of others -arrogance is not an endearing trait.

I indeed do not hold the modal person in high esteem. It is them who make democracy ork the way it does, it is them who accept that the good are told to suffer under the minority of fools.

Because I object to being treated like a fool whereas most accept that and thus democratically ´make´ it law, I am peceived as arrogant by you and a number of others. Well, tant pis.

As to the subject;
- helmets offers protection, per definition
- helmets affect behavior
- the resultant is not per definition a lower risk

[Josh B]

I indeed do not hold the modal person in high esteem. It is them who make democracy ork the way it does, it is them who accept that the good are told to suffer under the minority of fools.

Because I object to being treated like a fool whereas most accept that and thus democratically ´make´ it law, I am peceived as arrogant by you and a number of others. Well, tant pis.

As to the subject;
- helmets offers protection, per definition
- helmets affect behavior
- the resultant is not per definition a lower risk

heres a little suggestion: try not to make it evident that the people you disdain are the same people you are in conversation with!

we come full circle:
- yes
- not true, as i said ages ago,peltzman effect is shown not to apply in cycling context
- therefore your conclusion is erroneous.

And at this point i should say the horse corpse is sufficiently flogged.

[tmoris]

I would never go skiing or cycling without one.. would also never allow my children without a helmet either..

[mjb]

I wear a helmet. Sometimes. Most of the time, really. Especially when its wet - as it's the low speed slips that its most likely to help with.

As to being a pedestrian, again you appear to be confusing statistical analysis for the population as a whole with personal risk analysis.

In my own life I cannot see how a helmet as a pedestrian could ever be relevant to me.

As a cyclist I do see how if might be and wear a helmet accordingly. Simples.

As to speed, I don't kid myself a helmet will magically make me invulnerable and there are other risks involved. I mitigate them as well as I can and thats as much as I can do.

It's neither complicated not contradictory.

Do you ever walk down steps, stairs, walk in wet or icy conditions, stand on a chair to change a light build? There are more head injuries from falling in these situations than cycling. Agreed it's a bigger population sample that do these things compared to cycling. But I'm assuming you are one of them. So as you say....it could happen....you are gambling....better be safe.

The reality is that people do need to make up their own mind and risk assess the situation for themselves.

[Franky Four Fingers]

Do you ever walk down steps, stairs, walk in wet or icy conditions, stand on a chair to change a light build? There are more head injuries from falling in these situations than cycling. Agreed it's a bigger population sample that do these things compared to cycling. But I'm assuming you are one of them. So as you say....it could happen....you are gambling....better be safe.

The reality is that people do need to make up their own mind and risk assess the situation for themselves.

I don't have any problem with people making up their own minds about wearing a helmet, you either wear one or you don't, it makes no difference to me.

It's just the whole "you're no safer wearing a helmet" thing that amazes me.

Proof and proof alone than common sense is slowly disappearing.

[Huertecilla]

It's just the whole "you're no safer wearing a helmet" thing that amazes me.

Still: it CAN be correct.
The cyclist's hard top does not offer much protection and what it does offer without any doubt can be easily more than negated by risk behavior.

As to the comparison with other activities, the risk resulted of cycling can be as low as may daily routine behaviour. That is the level at which a cyclist helmet can easily be discarded as that is apparently an acceptable risk level since we do not wear one walking, on household folding stairs or hiking. Are we no to use helmets hiking too, with all the lycro dork stuff, twin sticks et al? Better make that madatory too.
And I am not mentioning playing football.

It is all a variable resultant and individual should be allowed to make their own risk assesment. Especially because of the limitations of the protection offered and changes in behaviour.

[Josh B]

Still: it CAN be correct.
The cyclist's hard top does not offer much protection and what it does offer without any doubt can be easily more than negated by risk behavior.

As to the comparison with other activities, the risk resulted of cycling can be as low as may daily routine behaviour. That is the level at which a cyclist helmet can easily be discarded as that is apparently an acceptable risk level since we do not wear one walking, on household folding stairs or hiking. Are we no to use helmets hiking too, with all the lycro dork stuff, twin sticks et al? Better make that madatory too.
And I am not mentioning playing football.

It is all a variable resultant and individual should be allowed to make their own risk assesment. Especially because of the limitations of the protection offered and changes in behaviour.

yes and donkeys can fly. If you launch them out of a cannon.

[100thmonkey]

Reading through this thread it is clear that quite a few of the posters have already had a bump on the head whilst not wearing any protection!!!!!!!

[Franky Four Fingers]

Still: it CAN be correct.
The cyclist's hard top does not offer much protection and what it does offer without any doubt can be easily more than negated by risk behavior.

As to the comparison with other activities, the risk resulted of cycling can be as low as may daily routine behaviour. That is the level at which a cyclist helmet can easily be discarded as that is apparently an acceptable risk level since we do not wear one walking, on household folding stairs or hiking. Are we no to use helmets hiking too, with all the lycro dork stuff, twin sticks et al? Better make that madatory too.
And I am not mentioning playing football.

It is all a variable resultant and individual should be allowed to make their own risk assesment. Especially because of the limitations of the protection offered and changes in behaviour.

You can't limit behaviour when chance rears it's ugly head and throws you on the floor.

[ralphy]

I appreciate the topic is about bicycle helmets, however I had a fairly slow speed ‘off’ whilst riding a motorbike and, although I did incur a head injury, there is no doubt* in my mind that the damage would have been far more severe had I not been wearing a helmet.

* And in the minds of those who attended me and those who subsequently saw the state of the helmet afterwards.

R

[Toodlepip]

The bit i can never understand when it comes the rotational argument is that unless you have a massive head, tiny shoulders and are on a unicycle, something else always hits before the rotational force can be applied to the head/helmet, the bike or the shoulders. aAs soon as that happens we're already seeing a big reduction in speed, i'm now desperately trying to remember if i've ever seen a rotational head/neck injury in the department on a cyclist, they are usually flexion/extension or lateral flexion injuries. This is purely based on what i see and it could be they all die at the scene.

The most likely way from a biomechanics point of view you would get a rotational injury is to fall off and be travelling so fast that as your head hits the road, a combination of the friction on the side of the head and the forward momentum, acts to twist the head around. the problem with this is the helmet saves you again as all the ones i've seen the lower helmet/tarmac friction vs scalp/tarmac means the head doesn't rotate

but hey once again it's just in my experience, but this is what i do for a living

Conventional wisdom is that many brain injuries that occur in cycling are the result of bruising to the brain as a result of rotation inside the skull. This is rather like the brain injuries in boxing which often come as a result of a 1-2.

As a healthcare professional I would have thought you would be aware of this...

[Josh B]

Conventional wisdom is that many brain injuries that occur in cycling are the result of bruising to the brain as a result of rotation inside the skull. This is rather like the brain injuries in boxing which often come as a result of a 1-2.

As a healthcare professional I would have thought you would be aware of this...

Whats your area?

[Toodlepip]

Whats your area?

[MartinCRC]

I've not read the whole thread so forgive me if my contribution offers no added value. I've cycled to and from work in all weathers, pretty much every working day for the past 15 years or so. My cycle route is about 3 miles each way and in a city which has reasonable provision for cyclists in terms of cycle paths and routes. For all but the past three years I did without a cycle helmet, not out of any strong feelings against them (other than of vanity) but out of habit and I suppose from the feeling of invulnerability that comes with relative youth. I had come off my bike a few times, on every occasion in icy conditions but usually at low speed negotiating turns. In every case, I was able to get up, dust myself off, and get back on my bike to continue the journey, usually sporting a bit of a bruise to a hip or elbow.

Then three and a half years ago I hit a patch of black ice at speed, probably 20 mph, and hit the deck before I knew what was happening. The side of my head impacted the ground and I was most definitely the worse for wear, to the extent that I could not get onto my feet, I did not know how old I was, and could not remember my home phone number when asked by the paramedic, having loaded me into the back of an ambulance. It took me over a month to recover fully from that knock to the head and I am pretty certain that I would have been much better off with a helmet. I've worn one ever since and far from becoming complacent about my safety on the bike, it serves as a reminder of my own vulnerabilities.

Martin

[Josh B]

Ok good so you are well placed to appreciate that the point is about a situation where the added weight of a helmet materially increases the torque so that it exacerbates a rotational injury. This can happen but it's a pretty rare injury compared to the other situations in which a helmet is likely to be a positive rather than a negative.

[Toodlepip]

Whats your area?

[Toodlepip]

Ok good so you are well placed to appreciate that the point is about a situation where the added weight of a helmet materially increases the torque so that it exacerbates a rotational injury. This can happen but it's a pretty rare injury compared to the other situations in which a helmet is likely to be a positive rather than a negative.

I doubt the weight of the helmet makes much difference. The head is already heavier than one might imagine.

There are two much more material risks associated with increased effective diameter of the head. The first is that while the head is relatively well protected by the shoulders, increasing the size of the head increases the ris k of impact, particularly glancing impact that can give rise to rotational brain injuries.

The second is that increasing the radius of the point of impact increases the angular momentum by the square of the radius. This means that increasing the radius by 1.41 will double the forces that give rise to rotational brain injuries.

If the average head is around 20cm on its longest axis (front to back) - 10cm radius - and the helmet is 2cm thick then this would increase angular momentum by 44%. Of course a side rotational impact would result in a much greater increase in forces.

[Franky Four Fingers]

Oh FFS

[Huertecilla]

http://www.sofoot.com/data/sofoot_bl...de-france1.jpg


I have not líve linked this photo so as not to give the long toed faction any reason to act injured.
Click at your own peril.

[Huertecilla]

I appreciate the topic is about bicycle helmets, however I had a fairly slow speed ‘off’ whilst riding a motorbike and, although I did incur a head injury, there is no doubt* in my mind that the damage would have been far more severe had I not been wearing a helmet.

Good point and yes, a motorcycle helmet woúld offer proteccion tp a cyclists´ head the way he is led to beleive about the token one sold for the purpose.

[Huertecilla]

One of the blokes with the task to fine us for not behaving safely taking a photo for the family album ending the career of Wilfried Nelisen

https://www.youtube.com/watch?v=pya6ZVW-oKg

[Chinnock]

Whilst messing about like young teenagers do, my sons friend recently crashed into the front of a parked car and smashed the windscreen head on. If he had not been wearing his helmet he would have been dead or severely brain damaged. Ironically my mate was the paramedic on the scene and showed me the photos from the incident. There are no guarantees regarding safety gear, however on this occasion the helmet did its job.

[Huertecilla]

https://www.youtube.com/watch?v=6zOY9ozfwCE

and even a full face motorcycle helmet is not designed to hit a solid object at that speed.

[scottbombedout]

Oh FFS

He did say as an engineer...........

[Huertecilla]

He did say as an engineer...........

and it is a nice change from dogma evolved by repeated hearsay from hot air.

[scottbombedout]

and it is a nice change from dogma evolved by repeated hearsay from hot air.

Please don't be too harsh on yourself.

[Huertecilla]

Please don't be too harsh on yourself.

Yes, I know.
Individual freedom has become just as boring a dogma today as foundation under opinion has.
Sorry for that.

[mrpgkennedy]

Conventional wisdom is that many brain injuries that occur in cycling are the result of bruising to the brain as a result of rotation inside the skull. This is rather like the brain injuries in boxing which often come as a result of a 1-2.

As a healthcare professional I would have thought you would be aware of this...

as you're clearly have more expertise maybe you'd like to explain why a 1-2 is so different from a road traffic accident, clue it doesn't involve maths

[Franky Four Fingers]

as you're clearly have more expertise maybe you'd like to explain why a 1-2 is so different from a road traffic accident, clue it doesn't involve maths

Doesn't take maths and engineering to make me realise you can bang your head when riding a bike and that just maybe a helmet might protect me.

[forpetesake]

This thread is beginning to do my head in.



(I have changed my mind about wearing a helmet though - Thank You everyone).

[Toodlepip]

as you're clearly have more expertise maybe you'd like to explain why a 1-2 is so different from a road traffic accident, clue it doesn't involve maths

Happy to explain, not sure why the question needs to be prickly...

1-2 causes problems not because of direct impacts but due to the rotational acceleration of the brain inside the skull. Not unlike the the acceleration that might be observed in a glancing blow on a cycle helmet. The change in direction in a 1-2 increases rotational acceleration, but there is evidence that rotational brain injuries do occur in cycling accidents so the rotational acceleration is clearly sufficient.

Thanks to those who were kind about the rational engineering approach. It's always worth looking at the evidence, and the net gives access at least to the synopses of academic papers...

[Huertecilla]

Doesn't take maths and engineering to make me realise you can bang your head when riding a bike and that just maybe a helmet might protect me.

Make sure that íf you do, that you wear one that actually míght.
The sad thing is that EN1078 is not telling you much and several not so homologated can even be a better choice.

Be véry VERY hesitant with elongated models and also with those not having a generous cut out for the neck.
The former increases possible torque on your brain by a blow and the latter can caúse neck injury.
Also make sure you have the temples protected.
You will find that many homologated models will nót do.

[Josh B]

I doubt the weight of the helmet makes much difference. The head is already heavier than one might imagine.

There are two much more material risks associated with increased effective diameter of the head. The first is that while the head is relatively well protected by the shoulders, increasing the size of the head increases the ris k of impact, particularly glancing impact that can give rise to rotational brain injuries.

The second is that increasing the radius of the point of impact increases the angular momentum by the square of the radius. This means that increasing the radius by 1.41 will double the forces that give rise to rotational brain injuries.

If the average head is around 20cm on its longest axis (front to back) - 10cm radius - and the helmet is 2cm thick then this would increase angular momentum by 44%. Of course a side rotational impact would result in a much greater increase in forces.

Fair points but again, the fundamental point I am making is that the situations where a helmet might exacerbate injury are a lower risk compared to the situations where wearing one might help (and consequently it makes more sense to wear one than not). Would you agree?

[Huertecilla]

Fair points but again, the fundamental point I am making is that the situations where a helmet might exacerbate injury are a lower risk compared to the situations where wearing one might help (and consequently it makes more sense to wear one than not). Would you agree?

No because the EN1078 cycle norm is not sufficient for higher risk reslutants. It is p.e. NOT intended for collisions with cars and offers very little laterel protection.

Imagine a hit with a hammer on the head and you would be better off with a cooking pot than with an EN1078.

PLÉASE have a look at the platic painted polystyrene packing material ones to realise what level of prtecttion is offered by EN1078.
By all means wear one but dó realise that the protection is limited and that behaviour is far more effective in lowering the risk.

[Josh B]

No because the EN1078 cycle norm is not sufficient for higher risk reslutants. It is p.e. NOT intended for collisions with cars and offers very little laterel protection.

Imagine a hit with a hammer on the head and you would be better off with a cooking pot than with an EN1078.

PLÉASE have a look at the platic painted polystyrene packing material ones to realise what level of prtecttion is offered by EN1078.
By all means wear one but dó realise that the protection is limited and that behaviour is far more effective in lowering the risk.

i am well aware of the limitations of helmets. I accept there are situations it will make no difference. That said and in that context I wear one because the situations where it will help are much more likely than the situations it will hurt me.

[MarkF]

It was interesting to note that, at the TdF presentation parade in Leeds last night, not one rider wore a helmet (not contractually obliged to) whilst whizzing around Leeds, 192 riders and I did not see one.

http://news.bbcimg.co.uk/media/image...kcavendish.jpg

[magirus]

I've been cycling for well over 40 years. I was a Firefighter for 32 years and wore a helmet every working day, and I've seen at first hand what happens to heads when subjected to impact. Any protection that can be used is better than none, and whatever the limitations of cycling helmets I always wear one, I believe it would be foolish and stupid not to. The skull is much more fragile than most folk might think. All IMHO.

[Josh B]

It was interesting to note that, at the TdF presentation parade in Leeds last night, not one rider wore a helmet (not contractually obliged to) whilst whizzing around Leeds, 192 riders and I did not see one.

http://news.bbcimg.co.uk/media/image...kcavendish.jpg

Closed roads, surrounded only by people who know what they are doing, no racing, a TV appearance right after.

I wouldn't bother either in that situation.