Fabian Cancellara sparks helmet debate on Twitter, says all cyclists should wear one

Previously I poked fun at those who advocated for helmets because their friend crashed while wearing one and so, of course, it must have saved them! However, I had never considered Philly's amazing experience that helmets had saved not just one mate, but a number of mates from head injuries. While one vague friend can easily be dismissed as an anecdote, Philly's "number of mates" have a clear statistical power that can not possibly be discounted.

Bravo to Philly for doing his bit to save heads. His neighbour would have cycled off to a certain death had not her eagle-eyed neighbour Phil spotted her and quickly run from his spot by his curtains and out the door to remind her that she'd forgotten her helmet.

I'm sure he also tells all his mates in the pub about the dangers of drinking without a helmet - alcohol being responsible for *far* more head injuries in our society than cycling. If it saves one head, a beer helmet surely is worth it? And Phil isn't the type of guy to be illogically singling out cyclists, oh no.

Go on, dashing Phil, you hero.

tomturcan: Quite. The EN1078:1997 standard is pretty pathetic. The Snell standard is a bit better. It's interesting to note that *no* helmet makers make safety claims in their marketing. They seem to be able to find improvements in aerodynamics, or weight, or style, etc., to trumpet, but never any improvements in safety. Kind of strange that, for a safety device, no?

Northernbike wrote:

has anyone from the 'helmet saved my life' brigade considered possibly learning how to ride a bike without falling off? it's not difficult, really it isn't

Sir - alas that particular bit of sanctimonious sniping has already been done a bit further up the thread. Do keep up please.

Paul J wrote:

tomturcan: Quite. The EN1078:1997 standard is pretty pathetic. The Snell standard is a bit better. It's interesting to note that *no* helmet makers make safety claims in their marketing. They seem to be able to find improvements in aerodynamics, or weight, or style, etc., to trumpet, but never any improvements in safety. Kind of strange that, for a safety device, no?

Well.... Kask make quite a thing of safety about their helmets in general, but then they come from a different direction and history to most helmet manufacturers. That aside I have to agree with you that it is certainly strange, bloody ridiculous really, that it is not front and centre in many claims.

nuclear coffee wrote:

Normally, I'd be charging for that information, since it took labour to acquire.

Pro bono, to crack a helmet in two you'd need to create at least 0.01 +/-0.005 square metres of crack (on mine anyway), you'd need about 200 +/- 100J. Really of course you're not going to create the one crack, and I haven't taken into account the covering, so 200J is highly unlikely to cause a major failure. Since unlike you I'm not actually trying to prove anything about helmets themselves, for any more I will have to charge. Given that unlike you I'm not trying to prove anything about helmets themselves, it's pretty shameful that I've done the work and you haven't.

You could have shown some evidence you did some work and didn't pluck numbers out of thin air.

What physical formulas are you using here?
What application of force (to the helmet) is performing 200J of work?

For a materials scientist you seem to have grossly simplified the problem.

For instance, a surgeons scalpel applied to the foam would require far much less force than a hammer to break it. (less work, joules).

A different experiment might try to laterally shear it, that has its own unique set of parameters.

You seem to have your materials science mixed up with collision physics. A full helmet doesn't lend itself to materials analysis i.e. they wouldn't work out the tensile strength of "expanded polycarbonate" (your original question) by stress testing a helmet.

You've provided unexplained answers to a problem which hasn't even been defined.

And it's still irrelevant because the foam is there to cushion the impact - it's supposed to give! (crack/compress)

Matt eaton wrote:

Everyone needs a helmet. Where else would you put your helmet camera?

Yeah, strap on a lump that stabs you in the head if you crash.

Or put it on your handlebars.

a.jumper wrote:

Matt eaton wrote:

Everyone needs a helmet. Where else would you put your helmet camera?

Yeah, strap on a lump that stabs you in the head if you crash.

Or put it on your handlebars.

Was there just the teeeeeenyist sense of humour failure there ?

A complicated, that one. Of course Cancellara is free to express his opinions, but he is also considered an "expert" with access to the mass-media, therefore an opinion maker. This makes the voice of contrarians even harder to be heard. His outrageous opinion should therefore be met with outrage. Australian cyclists are already paying the price for daft regulation. Fortunately, many replied to his blog with the necessary vigour. His next tweet will surely read: in Holland, no one wears helmets when cycling through town, and cycling accidents are the lowest worldwide. Why is that? Makes no sense to me.

HarryCallahan wrote:

nuclear coffee wrote:

Normally, I'd be charging for that information, since it took labour to acquire.

Pro bono, to crack a helmet in two you'd need to create at least 0.01 +/-0.005 square metres of crack (on mine anyway), you'd need about 200 +/- 100J. Really of course you're not going to create the one crack, and I haven't taken into account the covering, so 200J is highly unlikely to cause a major failure. Since unlike you I'm not actually trying to prove anything about helmets themselves, for any more I will have to charge. Given that unlike you I'm not trying to prove anything about helmets themselves, it's pretty shameful that I've done the work and you haven't.

You could have shown some evidence you did some work and didn't pluck numbers out of thin air.

What physical formulas are you using here?
What application of force (to the helmet) is performing 200J of work?

For a materials scientist you seem to have grossly simplified the problem.

For instance, a surgeons scalpel applied to the foam would require far much less force than a hammer to break it. (less work, joules).

A different experiment might try to laterally shear it, that has its own unique set of parameters.

You seem to have your materials science mixed up with collision physics. A full helmet doesn't lend itself to materials analysis i.e. they wouldn't work out the tensile strength of "expanded polycarbonate" (your original question) by stress testing a helmet.

You've provided unexplained answers to a problem which hasn't even been defined.

And it's still irrelevant because the foam is there to cushion the impact - it's supposed to give! (crack/compress)

As previously stated, I do not spend my own time explaining formula, finding data and doing calculations for lazy and ungrateful people for free. Nothing I used was propietary, and my question was entirely well-defined, thank you very much, so if you can't answer it that is entirely down to the work I have done and you have not.

I suppose what remains is for me to call you a passive aggressive douche for asking a question with a clear implication ("where does the energy go?") without providing clearly relevant information (such as the amount of energy we might be talking about), and an ungrateful douche for your behaviour towards someone who has provided you with at least some of the relevant information.

Chrisc wrote:

In April I hit a stone wall descending at 40mph after getting into a speed wobble and slid 25 yards to a halt. Broken shoulder blade, collarbone, 6 ribs, dislocated shoulder and a broken/ground away Giro helmet. I can remember the impact and sliding down the tarmac with my helmet grinding.
I am thankful I was wearing it.

This said, I didn't wear a helmet on my first ride after the accident (almost 4 months later and still unable to ride a road bike) on my hybrid because it was a gentle pace to test things out.

I will always wear a helmet on a road bike where I am riding at speed but will continue to ride in a cap on my hybrid when going to the shops or similar.

I'm much the same. If I'm going out for the express purpose of riding my bike I'll put my lid on. Also at the BMX track or trails I always lid up (but not always at the skatepark or on street). If I'm going to the shops or similar I don't really want to have to carry an extra thing with me. It's already a point of pain to have to remove lights etc. and carry a heavy lock (which seems even heavier on the way home with a load of shopping).