Only five cycle helmets available in the UK get recommended status in new safety testing

david rides wrote:

Why should we have to wear something annoying, stupid looking and not very protective, just because uk drivers can't drive correctly around us?

Er, because uk drivers can't drive correctly around us.

Except for Hedkayse, which not only performs close to the Hovding, but is genuinely multi-impact. In some tests it's been hit 300 times and still works fine... So horay, no longer is your only option an expensive consumable made out of cheap packaging material!
Have a look for yourself: hedkayse.com

kevvjj wrote:

Totally pointless British statistics. So, how many of the 40 cyclists a day admitted for head injuries were or were not wearing a helmet? What if all 40 were wearing a helmet at the time of the accident? What would this tell us about the effectivness of a helmet?

Totally pointless comment too.  If none of the 40 were wearing helmets, what do you think that would tell us about the effectiveness of a helmet?

Totally pointless reply too. If none of them were wearing helmets it would tell us absolutely nothing at all about the effectiveness of helmets.

Here's a slightly crazy idea.

Why don't you read the research mentioned in the article?

Olivier and Creighton is a really detailed look at injuries sustained by helmeted and non-helmeted cyclists.

Read it ages ago. It adds nothing at all to the original quote from Folksam.

Here's a slightly crazy idea.

Why don't you read the original quote from Folksam (it's in italics so easy to find)

It is meaningless.

You wanted to know how many of the admitted head injuries were wearing helmets.

The research detailed in Olivier and Creighton answers that question.

Read the research and the quote will have the context you desire.

with an updated Australian standard released only on 22 May I'm yet to see how our regulations now compare, but I know reference was made to VT. I'd like to see how VT do their testing. Traditionally the Australian standard has been more stringent than EN or CPSC  which you'd expect where helmets are compulsory. I'm hoping we might be getting closer to a common standard, might make some of these helmets more affordable to Aussies who have no choice but to wear one.

This website might explain it more clearly: https://webarchive.nationalarchives.gov.uk/20100210042953/http://www.dft...

In short, it's a measure of deceleration. If a moving object (i.e. your head) hits a hard surface (i.e. the road), it stops very suddenly - the deceleration is very high. A helmet is designed to reduce that deceleration - rather than stopping suddenly, your head stops more gradually, as the helmet deforms. It might be more obvious if you think about jumping onto a crash mat versus a hard floor, or even between braking to a stop versus riding into a wall. The change in velocity is the same (from whatever speed you were moving at to zero), but the distance/time over which that change occurs is greater.

"g" is the acceleration due to gravity, which equals ~9.8ms-2. Acceleration is often measured as a multiple of g rather than the absolute value. The wikipedia article gives some examples: https://en.wikipedia.org/wiki/G-force

So the helmet passes if it reduces the deceleration of you head below 250 g.

Thanks the wiki was more helpful particularly

"The human body is flexible and deformable, particularly the softer tissues. A hard slap on the face may briefly impose hundreds of g locally but not produce any real damage; a constant 16 g0 for a minute, however, may be deadly."

I know! It is a bit of an obscure concept. But the important thing to understand is the 'deadliness' of 'g' depends on the amount of time it's in effect.

So 9g can kill a fighter pilot becuase it happens over a number of seconds, where the brain is fine, but it's the blood draining out that means they fall unconscious and crash into the ground!

65g can absolutely can kill you if you're unlucky, but on the whole is survivable. It depends on location, direction and other factors like age or hydration levels - and most importantly, previous concussions. A good bash on the head in Rugby could easily be about 65g, which is where you start to experience concussion. If they're already suffering concussion, a second hit is extremely dangerous and could kill them, which is why nowadays if they have any kind of serious head impact, they get led off the pitch (usually against thier will!).

250g is basically just an industrywide accepted 'survivable' level. Above that, your chances are getting pretty slim. Below that you've got a more that say 50% chance of getting through it, albeit with come concussion.

The 'time' thing is important here, as most impacts occur in milliseconds, and the G-force experienced depends on the input speed, how far your head travels and how long before it stops. Lower G is always better, but there is an element that you can experience a very high G for a tiny amount of time and it's better than a lower G for much longer, which can tear the brain more.

It's really more about the change in momentum necessarily than the straight G number - think big change in momentum of your brain sloshing about inside your skull is what does all the mashing, neuron breaking, brain swelling and blood cutting off damage that kills people. But that takes us into more complex maths (which is actually used in car design) but for most people the G number is closely related enough to the more complex calculation, to more importantly be easily used and understood in normal life.

Mine's never triggered except the one time it should have, and it was a most impressive exerience. It also avoids the risk compensation you get wearing a helmet. Don't believe it? Try going without for a ride, and see how descents feel.

That said, it only suits flat bar commuting, so I use a helmet for other use cases. It also takes getting used to, as actually helmets do too- though we've all forgotten.

Sorry boss, I can't come in today...  ...there's a headwind.