that'd be while doing lengthy fast rides on the road bike as opposed to short trips around town on the beater.
Which is a common position but one I find odd because these things are designed for low speed impacts.
CityCyclingEdinburgh Forum » Debate!
THE Helmet Thread
(895 posts)-
Posted 11 years ago #
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"Which is a common position but one I find odd because these things are designed for low speed impacts."
My experience of crashes so far is that the actual impact with the road isn't all that bad compared to sliding along it afterwards to a stop. Main purpose of the helmet then being that it will hopefully get ground away by the tarmac instead of my head. Same for gloves.
Actually there's some more interesting physics going on here. Say if you fall over while stationary your head hits the ground at 8mph - in the range in which a helmet is supposed to be effective. Now imagine riding at 20mph and you hit the side of a car like a wall. Helmet won't do as much as the 'impact speed' is clearly 20mph.
Now, imagine riding along at 20mph but you fall off in a manner such that the vertical speed of your head is 8mph when it hits the ground. What's the impact speed? 20mph? 8mph? something else?
It helps to separate vertical and horizontal velocities. An oft repeated fact being that if your fire a bullet horizontally out of a gun and at the same time drop a bullet from the same height they will both hit the ground at the same time. The fact that the bullet is going horizontally at 800mph or whatever doesn't matter because gravity acts vertically.
Think I'll have to get the vector diagrams out to try and resolve this. My gut feeling is that if your are falling off at speed onto a reasonably flat and smooth surface then the impact speed is your vertical speed. That is the fact the ground is moving from your point of view doesn't matter all that much as far as that initial impact goes.
Posted 11 years ago # -
Standard Grade physics and shooting minkeys.
I've read one paper on the ground friction. It was one of the worst papers I've read on this as they changed their protocol part way though because they were worried about damage to their dummy.
I seem to fall off a lot less than people who wear these things but even so I've never slid along the ground.
Posted 11 years ago # -
This is not relevant to the debate but I couldn't help but notice what the google results are for 'helmet thread' ;)
Posted 11 years ago # -
http://www.bikeradar.com/mtb/news/article/smith-forefront-all-mountain-helmet-launched-37704/
saw this on my news feed
@wee folding bike
I had never had an off that really involved a head strike
until i had that off thanks to the taxi/pothole
Im still convinced the helmet saved me skin and at least a very sore headPosted 11 years ago # -
Managed to keep mine off all summer.
Posted 11 years ago # -
On the fore front hat piece.
It says the material absorbs 30% more energy but does't say if this is for the same mass or volume of material. It then fails to say whether this translates to the hat doing the same or have they just aimed for the 12 mph limit with less material. If they have increased the hat energy absorption by 30% then this means that it will have the equivalent of a normal hat's 12 mph performance at a whopping… 13.7 mph. It doesn't increase the speed of impact by 30% because energy varies with the square of speed.
Posted 11 years ago # -
http://www.newstatesman.com/lifestyle/2013/08/b-how-not-die-bike-london
"12. Nurses treat you better if you were wearing a helmet when it all went wrong. Even if the helmet actively made your injuries worse, the nurse is slightly less likely to badmouth you to the doctor inspecting your face/remains of your mouth. Wear a helmet but know it’s for nurses, not your own head."
OT..."15. Nobody likes the guy on the fixie bike who balances at the lights. Put your foot down. We’re grown-ups. We’re not playing that game where the ground is lava."
Haters gunna hate.
Posted 11 years ago # -
Bradley Wiggins is at it again with his nonsense: http://www.bbc.co.uk/newsround/23782673
Posted 11 years ago # -
Well that's interesting. I thought he claimed that he was ambushed and didn't mean it the last time.
BTW… why were you reading BBC children's news? It's not the same without John Craven.
Posted 11 years ago # -
Someone on Twitter linked to this story - I assure you I don't frequent the Newsround website ;)
I do find the comments from "children" on that article interesting. I think it's a bit doubtful that children wrote any of them. They look as though they were written by adults trying to write the way they think children write - but using words like "infrastructure" and "mandatory" tends to give the game away...
Posted 11 years ago # -
Brad changes his mind with the wind. I expect next week he'll be saying we should ride in stetsons and he'll be aiming to win the Tour of Lombardy in 2014.
Posted 11 years ago # -
That story was on the telly, my son was watching it and I exclaimed "What?" when Wiggo mouthed off. "Rubbish!" I continued, then seeing my son's puzzled expression (how could I question his hero?) I added "Well, I don't agree with him."
Posted 11 years ago # -
I'm having a discussion on a cycling forum at work at the moment about the merits or otherwise of helmets. Someone has pitched in with an observation that their friend works for the Brain Injury Trust, and that the consequences of a brain injury are dreadful (which of course, they are). I'm trying to encourage a sense of balance and to say that really, cycling just isn't all that dangerous. Talk of brain injury in the context of cycling is (I hope) as relevant as in the context of walking. In other words, not very. We're not very good at assessing the risk of high impact, low likelihood events like that.
So, I'm trying to find out some reliable stats about the number of cyclists who actually are seriously brain-injured every year, and to compare that in a meaningful way with other sources of brain injury. Something like '0.1 injuries per million hours of exposure, or somesuch'.
The cycle helmets website has some information, but it's not much use because saying on its own that 7% of head injuries were cyclists doesn't tell you if cycling is particularly dangerous. (compare fliffle board users, for whom there were two serious head injuries in 2003 in the UK. Doesn't sound bad until you realise that there are only two fliffle board users in the UK).
Do you know of any reliable, robust data that shows how likely you are to get a serious head injury from a range of common activities (including driving, walking and cycling)?
Posted 11 years ago # -
I'll just leave this here:
http://road.cc/content/news/98455-wiggle-rides-twitter-storm-over-make-helmets-compulsory-blog
I'll be on my way.....*whistles innocently*
Posted 11 years ago # -
@allebong I think Wiggle may be a bit biased given they sell the things...
Posted 11 years ago # -
I just think I'd look even sillier if I superglued my GoPro to my forehead.
Posted 11 years ago # -
The "Booby traps set on cycle path behind Davidsons Mains Tesco" thread made me think about this subject while I was cycling home along the NEPN this evening.
Let's say you were caught out by such a rope at head height across a darkened path - what is likely to happen to you? I would assume that your bike would continue forward, you wouldn't, and you would be thrown fairly violently backwards, with the back of your head smacking into the ground. Let's assume that this will happen at least _some_ of the time, for the sake of the following question (I know it won't happen all of the time).
If this was on a tarmac path (I assume that's what their surface is on NEPN?), you would be at serious risk of death, since the back of your head hitting a hard surface such as this has that potential. As far as I am aware, at least.
Therefore, I'm interested in hearing your views on this. Personally, I feel this is enough justification to persuade people that they would be better off wearing a helmet. I am quite sure there will be opposing views on this! And I am interested in hearing them.
Discuss!
Posted 11 years ago # -
@mkns -
Its all personal choice and while some people may decide to change - you wont persuade helmet wearers to give them up any more than you will persuade non-helmet wearers to wear one.
As to your original point, I think in pretty much all circumstances you would see or 'have an awareness of' something at the last nanosecond - and while you will probably have an off, it wont necessarily be straight backward.
Pretty much every time I have come off (clipless incidents and offroading usually) its been my elbows and hipbones that got it.
Posted 11 years ago # -
If the wire were to be at approx forehead height...
A helmeted cyclist might snag on the wire, tearing their head off.
While an un-helmeted cyclist might pass under with just abrasions to the forehead...
Posted 11 years ago # -
Helmets have more polystyrene at the front than the back. They are better for when you fall off on the tram lines when you will be going sideways/forwards
There was a chap who died at Haymarket a couple of years back, in ice, I think whilst carryin a child? Slipped and fell backwards.
Our heads then seem to be more protected at front, with or without helmet
Posted 11 years ago # -
My aunt had a degenerative brain disease that meant she was prone to fall backwards in the way mkns describes. It was suggested she wear a helmet for walking. I can see the sense in that.
As I see it for ordinary people (even those cycling into wires across paths) there's a tightly defined set of circumstances in which a helmet would make a difference, and a much larger set when it wouldn't. The tightly-defined set are, in my view, sufficiently improbable that on balance helmet wearing isn't worth it. (for example, you've got to hit the wire and go straight back and your hands and elbows have to stay in front of your head and you've got to not twist at all so that the first thing that hits the ground is your head rather than your shoulder and so on).
Must stop now: I need to buy a Lotto ticket for Saturday before I go to bed...
Posted 11 years ago # -
All interesting points. Completely separately, I just came across this video about an invisible helmet.
Posted 11 years ago # -
Too early Greenroofer. You have less chance of surviving to Saturday afternoon than you do of winning the lottery. Break even is Thursday afternoon.
Posted 11 years ago # -
@ mkns
"If this was on a tarmac path (I assume that's what their surface is on NEPN?)"
The attack (for that's what it is) happened on a track adjoining the path proper. It's bumpy, muddy and covered in gravel and larger stones. So basically I suppose you could argue that a helmet might either prevent you having direct contact with the big stones or - if particularly unlucky - direct a long, pointed stone right at your skull. Frankly, I think the odds are far more favourably stacked towards the former though
Posted 11 years ago # -
I bought a new helmet the other day from EBC. They have Carrera Pistard Helmet (not the most catchy name) on sale with 40% off. I've had my specialzed a couple of years now? and taken a couple of falls, plus its looking a little tired and I was lusting after something more roadie like, the spec being a distinctively MTB helmet.
Posted 11 years ago # -
That is going to be my new insult of the week!
Posted 11 years ago # -
Just thought after posting about my flat cap on the other thread.
Never put a helmet on when just going to the shops in 'civvies' on the upright bike, but always put one on when in my lycra gimp suit on the commuter or road bike.
Is people's choice to wear a helmet or not based on vanity? Never actually thought about why I don't put one on going to the shops, perhaps because it's less than a 2 mile return journey, perhaps it is vanity. But, when I cycle to work, even the full cycle less than 2 miles of that is on roads...
Posted 11 years ago # -
I wear a helmet when ever I ride, no matter wear. My last two helmets have saved my bonce a couple of times after falling off. I fell to the ground in both incidents and the helmet did what I bought it for, protected my head. No motor vehicles were involved. I didn't have any head injuries, instead huge bruising to the hip/thigh (different sides). At the time I may have been distracted from recalling that my head perhaps hit the deck as I had no cuts or bruising to my head. Afterwards, on reflection I felt I'd not noticed my head as it was not injured, which I took to be as a result of wearing my helmet and it doing its job. I did have slight neck strain both times in the following few days, so I know my head was jerked in some way. I replace my helmet after I have a fall as a matter of course. I know my helmet would not offer much protection to my body in a veh collision but I wear in to protect my head in case of a fall, which may result from being hit by a veh in future. I hope I never have to find out if that theory works.
Posted 11 years ago # -
Bald, I wouldn't say vanity but it's definitely less faff to not wear a helmet. Especially if you're around town and plan on doing anything off the bike, etc.
Dave, this is one of those justifications I have a problem with because you can't say that your helmet saved your head in those offs. Some would suggest that the neck strain could have been caused in part by the helmet.
Posted 11 years ago #
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