The CycleChat Helmet Debate Thread

[Profpointy]

As someone not having done any research into this subject could you please explain the geometry to me please? Or a link to to the research paper?

1 if your head is bigger it is more likely to be hit
(this surely can't be in question)

2 likelihood of being hit is proportional to cross-sectional area (as opposed to diameter). This seems so basic an idea that any "paper" would be lost in the mists of time. The very concept of "pressure" assumes it doesn't it? Or the idea of inches if rain maybe.

3 fag packet calculation: head is 6" diameter, helmet is 8" diameter, so the ratio of being hit with/without is 64/36. Feel free to choose other numbers, but I challenged anyone to not get between 50 and 100% increase

 

[Rusty Nails]

Yes there’s a paper that shows you are more likely to end up in hospital with a head injury if you wear a helmet. There’s another paper than shows a helmeted head will make contact with the ground in 70% of cases where as without the helmet they’d be no impact. Plus the introduction MIPS clearly indicates that a problem has been found with helmets causing rotation injuries to the brain, during accidents..

Another request for those papers please. If you have seen them it should be easier for you to find them than for me to search for vague terms, or plough through papers looking for reference to 70%.

 

[Rusty Nails]

1 if your head is bigger it is more likely to be hit
(this surely can't be in question)

2 likelihood of being hit is proportional to cross-sectional area (as opposed to diameter). This seems so basic an idea that any "paper" would be lost in the mists of time. The very concept of "pressure" assumes it doesn't it? Or the idea of inches if rain maybe.

3 fag packet calculation: head is 6" diameter, helmet is 8" diameter, so the ratio of being hit with/without is 64/36. Feel free to choose other numbers, but I challenged anyone to not get between 50 and 100% increase

If I drop a cricket ball and a football on the floor they both have an equal chance of hitting it even though the football is many times larger, except if they both are flying along parallel to the floor. If someone throws something at both balls then there is an increased chance of hitting the football.

Unless those not wearing a helmet have found a superhuman way to stop their head just two inches from the ground this argument is false, imo.

 

[mickle]

1 if your head is bigger it is more likely to be hit
(this surely can't be in question)

2 likelihood of being hit is proportional to cross-sectional area (as opposed to diameter). This seems so basic an idea that any "paper" would be lost in the mists of time. The very concept of "pressure" assumes it doesn't it? Or the idea of inches if rain maybe.

3 fag packet calculation: head is 6" diameter, helmet is 8" diameter, so the ratio of being hit with/without is 64/36. Feel free to choose other numbers, but I challenged anyone to not get between 50 and 100% increase

I'm no helmeteer but I think your method is flawed. If you have two balls of different diameter but of similar weight travelling at Xmph towards a brick wall / kerb / Range Rover they both have a 100% chance of hitting. Their diameter has zero bearing on the likelihood of them making contact with the target.

 

[MontyVeda]

the larger helmeted head argument isn't one I personally use... but years ago when I first donned hard hat when working on a site around scaffolding, I was constantly hitting the helmet on the scaffold, window frames, walls. It took a week or so to get accustomed to my new larger head.

I've skidded on ice numerous times and come off the bike sideways, yet never once hitting my head on the ground. I think we instinctively do what we can to protect our heads. Something learned as toddlers, I expect. Had I been wearing a helmet, it may have hit the ground, but honestly, I can't really say. All i know is that i have, to date, managed to keep my head off the ground in such events.

I've gone over the handlebars once and I couldn't stop my skull from hitting the ground. It hurt but it didn't break. Had I been wearing a helmet on that occasion, it might have broken, and I might have thought it saved my life.

 

[mjr]

I'm no helmeteer but I think your method is flawed. If you have two balls of different diameter but of similar weight travelling at Xmph towards a brick wall / kerb / Range Rover they both have a 100% chance of hitting. Their diameter has zero bearing on the likelihood of them making contact with the target.

Surely not 100% chance on the brick wall or Range Rover unless you already know it's heading perfectly towards them — which hints at the correct reason why it's probably something between no-change and 70%: what if the brick wall is only part of the possible target area? Why would cricketers bowling at an unprotected stump have a better chance of making contact if they use bigger balls?

 

[Dave Davenport]

the larger helmeted head argument isn't one I personally use... but years ago when I first donned hard hat when working on a site around scaffolding, I was constantly hitting the helmet on the scaffold, window frames, walls. It took a week or so to get accustomed to my new larger head.

I used to sometimes work under London underground trains, never hit my head until they decided we had to wear bump caps (bit like a plastic, padded cycling cap). From then on I was forever whacking my bonce and straining my neck, because it was only an hour or two a couple of times a month I never got used to it, it's a good job there wasn't a swear box.

 

[classic33]

Surely not 100% chance on the brick wall or Range Rover unless you already know it's heading perfectly towards them — which hints at the correct reason why it's probably something between no-change and 70%: what if the brick wall is only part of the possible target area? Why would cricketers bowling at an unprotected stump have a better chance of making contact if they use bigger balls?

Assuming that the bigger ball is still used to space the stumps, would their chances of hitting the unprotected stumps increase.

You're assuming that someone has aimed to hit whatever they make contact with.

 

[matticus]

I'm no helmeteer but I think your method is flawed. If you have two balls of different diameter but of similar weight travelling at Xmph towards a brick wall / kerb / Range Rover they both have a 100% chance of hitting. Their diameter has zero bearing on the likelihood of them making contact with the target.

A kerb is what - 4-5" high? (typically) And you think it's no harder to hit with a cricket ball than with a beach ball?

(I have very real experience of hitting my head against kerb recently - it was a lot more painful than being hit by a van* about 0.5 seconds earlier!

*which you'll note was a much larger object, with a flat front.

 

[Profpointy]

If I drop a cricket ball and a football on the floor they both have an equal chance of hitting it even though the football is many times larger, except if they both are flying along parallel to the floor. If someone throws something at both balls then there is an increased chance of hitting the football.

Unless those not wearing a helmet have found a superhuman way to stop their head just two inches from the ground this argument is false, imo.

Hang on a minute - if you take that argument to it's logical conclusion hitting your nose is equally likely as hitting your whole head. Or to put in another way you are certain to hit your head on every occasion, or at least every mishap.

 

[glasgowcyclist]

I'm no helmeteer but I think your method is flawed. If you have two balls of different diameter but of similar weight travelling at Xmph towards a brick wall / kerb / Range Rover they both have a 100% chance of hitting. Their diameter has zero bearing on the likelihood of them making contact with the target.

You need to allow for there being an intervening solid object, like a parked car, a wing mirror, a kerb, or a piece of street furniture which your helmet snags on or glances when your bare head would have missed it.

 

[Profpointy]

I used to sometimes work under London underground trains, never hit my head until they decided we had to wear bump caps (bit like a plastic, padded cycling cap). From then on I was forever whacking my bonce and straining my neck, because it was only an hour or two a couple of times a month I never got used to it, it's a good job there wasn't a swear box.

I have it on good authority, (from a chap who supplied rescue stretchers to the navy,) that they'd rescinded a similar instruction for certain tasks on submarines (dunno if it was maintenance crew or emergency scenarios or what, as they clearly don't habitually wear hard hats). It seems the sailors were getting neck injuries (presumably minor) from banging their heads more, which overshadowed the benefit)

As another side, in caving we wear helmets as you bang your head a lot, which can make you dizzy if you wrench your neck even in a helmet, but on balance it's still worth it as you get somewhat used to the extra clearance you need to leave. But even after 40 years I still hit my head somewhat more than I would bare headed, but it hurts less, notwithstanding the neck wrench dizzy thing which is maybe worse. There's also some protection from (small) falling rocks even if it won't save you from one the size of a washing machine.

 

[Rusty Nails]

Hang on a minute - if you take that argument to it's logical conclusion hitting your nose is equally likely as hitting your whole head. Or to put in another way you are certain to hit your head on every occasion, or at least every mishap.

If your nose had separated from your head prior to the fall then you are correct that the logical conclusion is that both have an equal chance of hitting the floor. In that specific case wearing a helmet would be the least of your concerns.

The pity is that logic has little place in this debate.

 

[matticus]

We do all need to remember that accidents - and impacts - come in many flavours. Nevertheless, I shall comment on this specific issue:

...
Unless those not wearing a helmet have found a superhuman way to stop their head just two inches from the ground this argument is false, imo.

Actually, I think we're all quite good at this. Imagine we're standing on a safe surface (trampoline, wodevva ..) I challenge you to hold your hands by hour sides as I gently topple you over sideways.
When you land on your hip/shoulder/etc, I'd wager that most times your average neck muscles will keep your head from impact. On the occasions it *does* hit something, it will be a lot more gently than your shoulder hits.

No superhuman powers required!

 

[matticus]

If your nose had separated from your head prior to the fall then you are correct that the logical conclusion is that both have an equal chance of hitting the floor

I've probably told this story before, but a schoolmate did once get hit on the nose by a bus as he stepped into the road. No other injuries - just a badly bruised conk