What in the hell is going on here? First CampyBob wanted to argue about an off-the-top-of -the-head calculation such as we engineers do all the time as a first approximation. It was a total insult to him. Why? Then Froze started chipping in because I was so forward as to have actually published a paper showing that bicycle helmets don't save lives but in giving people confidence in increased safety might even caused more harm than they do increased safety in that regard. I stated plainly that the most common bicycle accident is a fall down and that helmets do help with those most of the time. But my almost fatal fall down with my head only 2' off the ground showed that helmets may not even help with those. Certainly there are all sorts of articles about increased safety from helmet use but these are all misunderstandings of what the statistics mean. And if you believe hard enough and click your heels together three times you can interpret anything to mean anything. Motorcycle safety helmets are another thing altogether and since I raced motorcycles and became the safety director of the AFM and went to Bell and spoke to them about it perhaps I have more knowledge about it than someone that thinks that anything with the word "safety" in it should be praised to high heavens. Now we have Brian complaining that I'm publishing threads about questions no one has asked. Would you like to know whether the carbon wheels that you're about to buy might not be such a good deal after all? Or that the latest rage of ceramic bearings is nothing more than hot air? As a sports rider would you be interested in discovering that tubeless tires are almost flat-less freeing you from carrying a 2 lb bag of spares along with you? Wouldn't you like to know that properly designed aero wheels not only make you faster on the road but do not disturb you any more than regular wheels in cross winds? This is a forum and if you don't like a thread you have no one forcing you to read it or to even believe it. Bickering for the sake of it isn't forwarding the purpose of this forum at all.