The CycleChat Helmet Debate Thread

[mjr]

I assumed the same and pedaled on, it did however put a big grin on my pro compulsion buddies face, so some good came of it I suppose.

If you don't want to stop, just shout back "where's yours? It'd be as useful!"

 

[ufkacbln]

Ridng home with my buddy last night and we caught up to a couple of joggers on the shared use, they very kindly moved right over to either side so that we could pass through the middle of them, as I went through one of them shouted at me;
"Where's your helmet?

My favourite (though a little dishonest) was a roadie who asked me this question

I replied that in the s8ame way that motorised trikes were exempt from helmet use, trikes were exempt from helmets as well due to increased safety

Cogs whirred, expression changed and the reply came back...


" Oh... I hadn't realised that trikes were exempt"

 

[ufkacbln]

It would be interesting to see where the helmet cracked.

It is usually at the points where there is so little material that only the cage keeps it supported

A total failure in design and function.

 

[ufkacbln]

You're looking in the wrong place.

£10 if you've got a small head - http://www.halfords.com/cycling/bike-helmets/adult-bike-helmets/trax-furnace-bike-helmet-54-58cm

Or £10 half price - http://www.halfords.com/cycling/bike-helmets/adult-bike-helmets/bell-avanti-bike-helmet-54-61cm

Both meeting EN1078. If I remember correctly, the last one I bought cost £40 from an LBS.

The appallingly poor standard that is not accepted by some event organisers as it offers inadequate protection?

 

[srw]

The appallingly poor standard that is not accepted by some event organisers as it offers inadequate protection?

And probably the same standard that the £160 job is made to.

 

[MontyVeda]

And probably the same standard that the £160 job is made to.

yeah but for £160, you get even more air vents.

 

[newfhouse]

I have a homeopathic helmet.

 

[ianrauk]

I have a buffed one

 

[MontyVeda]

calling @Fnaar

 

[Shut Up Legs]

I have a mandatory one.

 

[Fnaar]

calling @Fnaar

I actually have a black one, (despite my sig line), but I don't use it often

 

[gds58]

Well, I'd rather the helmet split than my head .

Much like the 'crumple zone' in a car, it is designed to do that whilst absorbing the impact forces and you don't need to be a Materials Scientist (as someone mentioned earlier) to be aware of that fact. Some people really do like to over-complicate things in order to bolster their own point of view.

MOD EDITED to remove Offensive remarks.

 

[mjr]

If only there was an archived collection of posts by materials scientists on here to which he could be referred.

Sarcasm or is there such an archive which I'm failing to find in the search? Think skull is the closest I found.

I think the web is actually very weak on explaining how helmets are intended to work. I'll go search for the example I saw before...

So do I, although i am not quite as oppressed as you on this score. I last wore it for last year's Brompton World Championship, and expect I will next wear it for the same event this year.

And is it scrutinised to check it's marked as compliant with the standard and within its expiry date, or is it the same "well that looks like a helmet" joke that happens at most helmet-forcing events?

 

[mjr]

I think the web is actually very weak on explaining how helmets are intended to work. I'll go search for the example I saw before...

OK, this is from the pro-helmet Transport Research Laboratory "PPR697" report used to save no children in Jersey by forcing them to wear helmets, which I don't trust on many things, but I hope it describes how helmets should work in the most optimistic/idealised manner. I quote from its section "Principles of cycle helmet design":

"In the process of absorbing a proportion of the energy of an impact, the structure of the helmet is usually damaged. This is an important characteristic of helmets: if the liner material was elastic the impact energy that was initially absorbed would be returned to the head later in the impact, thereby greatly reducing the effectiveness of the padding. Liner materials are therefore primarily plastic in their deformation characteristics."

I understand this to mean that it's not so important whether a helmet split up or not, as long as it stayed together long enough to transmit the force - if it shattered on impact, then its capacity to spread the force from the point of impact will have been severely limited with most of the force going through the smaller impact fragment and, in short, the helmet didn't perform as it should.

What's important is whether the liner material deformed and stayed deformed - if at the end of it all, there's no sign of liner deformation then the energy was probably returned to the skull in an elastic rebound of the liner material and, in short, the helmet didn't perform as it should.

Cunobelin's Google'd examples are the only ones I found searching this thread and it's not clear whether they're deformed or not, although they've definitely split. I'm surprised so few pictures of used helmets have been posted - is that itself suspicious?

 

[martint235]

Much like the 'crumple zone' in a car, it is designed to do that whilst absorbing the impact forces and you don't need to be a Materials Scientist (as someone mentioned earlier) to be aware of that fact. Some people really do like to over-complicate things in order to bolster their own point of view.

You really don't get this, do you? Guess what the crumple zone of a car is meant to do? It's, as the name suggests, designed to crumple as it absorbs impact. Not split and let whatever you've hit into the cabin of the car with you. A cycle helmet should be designed in exactly the same way, to crumple and absorb the force of the blow not split into two or crack. Given just how many helmets do split or crack on impact, you can easily understand why manufacturers are reluctant to release data around their performance in various impacts.

I realise I'm on a hiding to nothing even trying to discuss this with you but given the progress we seem to have made with Justin, I thought it worth at least one go.

MOD EDITED to Remove personal comments