19 pages of polar opposite views and (almost)all dealing in extremes...
Let's face it, nobody needs
a cycling helmet until that one pivotal moment when when it becomes the deciding difference between a couple of paracetamol and a new helmet or an air ambulance and skin grafts (at best?).
You can quote all the research/stat's you like, all funded by one pro/anti lobby group or another, but there is more to falling off a bike and landing on your head than rotational wotsit and brian(sic) damage...
worn helmet projects maybe 3cm out from the sides of your skull/face, more at the front/rear, to ensure that in the kind of 'off' that most
cyclists are likely to encounter the helmet hits the ground first. This is ostensibly to prevent the kind of abrasions that can be 'uncomfortable' at best to life threatening at worst.
You have nerves running up your neck and around your head that any competent martial artist experienced in certain schools will tell you are ideal for all sorts of effects from simple discomfort, through disablement by stunning, to instantaneous death.
You also have an optic nerve running up each temple that is very vulnerable to even the slightest impact, leading to simple dizziness and disorientation to instant and irreperable blindness!
Now, you could very easily cite the example of bare knuckle pugilists beating each other bloody to poo poo just that one last sentence alone, and you would be right, but then I could just as easily cite the case of a woman who lost the sight in one eye when she accidentally clashed heads with another commuter on the Tube; swings and roundabouts...
You just do not know
what effect any given injury is going to have under what circumstances, until it happenes.
A collegue of mine lost a friend due to injuries sustained in a motorcycle accident a few years ago; he had a very big 'off' in an RTA but actually walked away 'unscathed' only to die in hospital three weeks later due to the mortal internal injuries he suffered because of the immense forces generated by the massive deceleration effect of the impact.
From personal experience I can concur with those who have said they have avoided injury from low hanging branches, hidden tree stumps, kerb edging, fly-posted signs at the side of the road (those ones they cable-tie to sign posts right about head height
), bus/lorry wing mirrors, you name it; any of which could have resulted in anything from ribald piss-taking (failing to unclip at traffic lights and hitting my head on the kerb
) to life threatening injury (as GM will testify, a wing mirror to the back of the head can have far reaching consequences
...and just for the record, no, even now I don't always wear my helmet