Originally Posted by
Joe Minton
corrado33, wphamilton:
I have a busy day & won't be able to respond in depth until this evening or tomorrow.
Both of y'all have asked good questions, made intelligent statements and made it clear that you have open minds --- those are wonderful things. I would be glad to answer, as best I can and as soon as possible.
If we can get other clear-thinking, open-minded and knowledgeable folks into this version of the helmet thread, then, perhaps we may all learn things about bicycle helmets that are helpful.
later,
Joe
Thanks for the confidence Joe, but in the interest of full disclosure I should mention that I often
don't wear a helmet when I estimate the odds of needing it are too low to be meaningful. That said, there's something you could shed some light on.
Helmets are commonly rated for 250 to 300g impacts. I have seen studies which suggested that for a perfectly linear, straight-on impact that it takes considerably more than that to result in a concussion, so on the face of it we might think that those helmets are insufficient. But two things occur to me about that: it seems like it would be difficult to have a hard impact
without having some rotational component (in which case less than 300g could cause a concussion, which might be prevented by the helmet depending on the angular vector), and that skull fractures are possible at lower g accelerations. Either point would weigh in favor of the helmet. Does that scan right from the vantage point of your experience?
Also, do you think that the newer double layers with differing densities will serve to reduce angular accelerations?
Regarding the pointy aero helmets, I always got a mental image of trying to do a back-fall or shoulder roll wearing one of those with a guaranteed neck injury. I figured that the pointy back was just a flimsy facade or break-away piece.