The best helmet is the one you are prepared to wear. That means you should be clear about the purpose it serves and the payoffs it introduces. I see quite several people these days whose helmet is a GoPro or LED lamp mount first and a head protector, second. Some of these are “flamboyant” – that is, the mount features gaffa tape, cable ties, et cetera.
This is an incredibly bad idea. The materials used to make helmets are fantastic things – strong, light, mouldable, eco-friendly – but none of them expect to have to be solvent-proof, and adhesives on gaffa tape are not chemically neutral or perfect.
So to my mind, there is no one perfect helmet. The most protective ones cover the ears: The lightest ones have to be thrown away every other year. The most aerodynamic ones are not good for mounting extras, GoPros, or Wotevs. So to be reasonable about it you have to accept that 2–3 helmets are probably right. Oh, and I forgot: I used to like those plastic dome jobs until one rider told me they were pure torture in the rain, with icy trickles of water delivered just inside your neckline.
All that said: THE most important thing about a bike helmet is, that it is not Thor’s hammer for cyclists. You cannot plow through everything and everybody in your path just because you are wearing a helmet: The most common fatality type in London is where a fully helmeted, hi-vizzed, belled-up, and well-lit cyclist imagines that they are therefore invulnerable, and they get eaten and squashed by a huge vehicle whose driver cannot see where they have positioned themselves. Far too many novice riders get a helmet and use the word ‘safe’. “I’m safe now”. No, you are not.
