I'm not repeating nonsense, and I hardly consider myself an expert. I am, however, a mechanical engineer who knows a few things about momentum, energy, and how materials behave under dynamic loading. I thought I'd point out that if the reason you don't wear a helmet is really that you think it has to absorb half a million foot pounds of energy to be effective, then your logic is ridiculous.

I don't judge people for choosing not to wear helmets. I used to commute without one. But when you use a silly number to support a decision not to wear a helmet in a thread about what helmet to buy, it is YOU playing the expert and begging to stir up the 'mindless' debate. I thought the OP might be interested in reality instead of hyperbole. It would be a shame if he made a decision based upon the uninformed idea that a helmet has to completely absorb every foot pound of energy from a 40mph collision with an SUV to be effective.