The CycleChat Helmet Debate Thread

[Big Andy]

Not sure i understand your point Adrian. Personally i would always choose a failed helmet over a failed head. The helmet was undamaged before the spill. There is no way to determine if it prevented injury. I can only surmise based on the experience of the spill that it probably did.

 

[stearman65]

Trialled my new haute coiture home made job today. Results, peak too long blocks forward view, sweaty in hot weather, made pedestrians get out of the way Maybe a winter hat???

 

[stearman65]

Nice handbag.

Wife's, got the rum n raisin cone money in it.

 

[srw]

Not sure i understand your point Adrian. Personally i would always choose a failed helmet over a failed head. The helmet was undamaged before the spill. There is no way to determine if it prevented injury. I can only surmise based on the experience of the spill that it probably did.

First, I'm glad you're OK.

Second, congratulations on adding to the mounting evidence that posting in this thread in support of the protective properties of polystyrene is correlated with hitting one's head soon afterwards.

Third, and the substance of the point - there is quite a lot of detail in the last 315 pages, but roughly speaking if polystyrene has cracked then it has transmitted all the force of the impact straight to your skull. The idea of a helmet is that the polystyrene doesn't crack, but crushes on impact, which spreads the force over a wider area. A cracked helmet has failed. You might want to take it back to the shop and complain.

So my suspicion, based on your photo, would be that it didn't prevent injury, except possibly some superficial grazing. In fact your skull was never going to be injured.

 

[Big Andy]

Srw. If you read my earlier post you will see i said it crushed and cracked, which can be seen in the picture so it has spread the impact over a wider area but has also cracked.

I find it somewhat amusing that you think posting in this thread has any correlation to anything beyond this thread.

In my opinion the helmet has very likely done what it is supposed to and protected my head against injury.

Stating as fact that my skull was not at risk is as laughable as it would have been if I claimed the helmet saved my life.

 

[srw]

Srw. If you read my earlier post you will see i said it crushed and cracked, which can be seen in the picture so it has spread the impact over a wider area but has also cracked.

I am not a materials scientist, but I'm sure one will be along shortly to explain using some very long words that the crack means that the benefit of the crushing has been lost.

I find it somewhat amusing that you think posting in this thread has any correlation to anything beyond this thread.

The correlation is merely my observation. A lot people seem to hit their heads after posting in this thread. As for why that might be, I suggest you read up on risk compensation.

 

[martint235]

Your skull tends to be more resilient than you think. A few thousand years, if not hundreds of thousands or millions, has gone into its development to help protect you against banging your head on a branch, hitting it on the floor or running off a cliff when being chased by a sabretooth tiger. Helmets have undergone a few years of development into helping them channel airflow, weigh less and be pretty colours.

On these pages I've seen many pictures of a failed helmet but never once a failed skull. My skull has to date never failed and I bang it a lot. And I mean a lot. And hard. Try being the height of a standard door. I do actually have a slight ridge in my skull though that corresponds to the end of a door frame, could be counted a failure I suppose.

 

[EnPassant]

My powers of recall are far from total, but my less than perfect memory of most of this thread is that those advocating helmet use nearly always have an apocryphal tale of somebody saved by one. Pictures of helmets with various damage also abound here and elsewhere, all captioned with something along the lines of 'that could have been my head'. Every one is aimed with sniper like precision at your emotional response core.

This is the first time I've seen anyone unfortunate enough to argue for helmets and then within a day or two have an accident where they have hit their head and the helmet has done some service*.

*I'll leave the materials scientist and those more knowledgeable than I to debate its effectiveness based on the damage incurred in this situation.

 

[Big Andy]

Must admit I was sitting on a nearby bench for a few minutes afterwards while attempting to pull myself together, while examining the helmet and considering how hard I recall my head hitting the ground this thread did come to mind. There is simply no way to know whether the helmet saved me from further injury, whether cuts and bruises or something more serious, i very much suspect it probably did and I certainly wouldnt want my un protected head to have hit the tarmac with the same force. I don't think the incident has affected my viewpoint in any way though. I am still very much pro-choice and don't think my habits when it comes to wearing a helmet will change, always when on the road bike and sometimes when on the hybrid.

I think we should fight any move for compulsion and also against those that are so dogmatic on either side of the debate that they cannot see any of the opposing points of view. Im not convinced that there is enough definitive research and evidence to be 100% certain on the issue.

Would be nice for better helmet testing standards to be brought in to aid the buyer when choosing, something I will be having to do at some point soon. I may start a "which helmet" thread!

I think in this incident the helmet has probably prevented some sort of head injury, hasnt done anything to prevent the back/side injury which is proving bloody painful today and I am more than prepared to accept that there are cases where a helmet will not help at all. I consider that I have pretty much got away with quite a nasty spill with nothing more than a few cuts and bruises and soft tissue damage, it could certainly have been much worse, broken ribs etc
Once I am back on the bike I will be popping back to the crash site to see if I can learn anything, I dont think I was going particularly quickly although it is certain that if I was going slower It either wouldnt have happened or I would have been able to save it. May have been able to save it if I wasnt using SPDs and could have got a foot down quicker too. At the moment I am putting it down to one just one of those things, a bit of a freak accident.aybe I need different tyres? Got 28mm Shwalbe Duranos on at the moment.

Of course the most important thing is that apart from some handlbar tape and a slightly binding front disk brake the bike appears to have escaped damage.

Happy and safe cycling everyone.

 

[doog]

Srw. If you read my earlier post you will see i said it crushed and cracked, which can be seen in the picture so it has spread the impact over a wider area but has also cracked.

I find it somewhat amusing that you think posting in this thread has any correlation to anything beyond this thread.

In my opinion the helmet has very likely done what it is supposed to and protected my head against injury.

Stating as fact that my skull was not at risk is as laughable as it would have been if I claimed the helmet saved my life.

Evidence of damaged helmets have been posted on this forum on numerous occasions. Every one has been dismissed with the usual disdain.

However its nice to know that your skull might apparently be more resilient than you think

Luckily for you it looks like your helmet prevented you from doing a skull resilience test

 

[swansonj]

I am not a materials scientist, but I'm sure one will be along shortly to explain using some very long words that the crack means that the benefit of the crushing has been lost.
....

I'm not sure about that. To whatever extent the polystyrene crushed, that presumably absorbed the same energy whether or not it also cracked?

 

[Wobblers]

Not sure i understand your point Adrian. Personally i would always choose a failed helmet over a failed head. The helmet was undamaged before the spill. There is no way to determine if it prevented injury. I can only surmise based on the experience of the spill that it probably did.

A failed helmet means it failed in its intended purpose - to absorb the energy of impact and reduce the impact forces (or more strictly, impact acceleration) to your head. The only mechanism by which impact forces can be reduced is by compression in the helmet. That your helmet cracked suggests that it failed in a brittle manner and did not compress. A "failed helmet" as you put it, does not offer any meaningful protection against serious injury whatsoever. In fact, by making it more likely that your head will collide with another object, it makes injury more likely.

ETA: It would be churlish not say "I'm glad you weren't badly hurt", so I'll just say I'm glad you're still here posting (and not drinking through a straw!) You helmet at least saved you from an unpleasant scalp injury so it would be wrong to suggest that it was useless.

 

[Justinslow]

Not sure if this has been posted already, apologies if it has

http://www.bbc.co.uk/news/world-europe-37213884

 

[Wobblers]

I'm not sure about that. To whatever extent the polystyrene crushed, that presumably absorbed the same energy whether or not it also cracked?

A helmet that cracks will has a diminished ability to compress. A crack is not a good thing to see in a structure that is designed to deform in a controlled manner. Brittle fracture is in no way controlled.

 

[Big Andy]

As i mentioned the helmet did compress, there are clear signs of this. What we cannot know is at what point the crack appeared, could be that it appeared after the compression phase of the impact, we simply do not know.