Posted By Kameron Kameron on 06/05/2013 02:03 PM
100% disagree respectfully. I for one have no doubt I am walking today because of that 250g foam on my head during my accident. If you had seen my helmet and pictured my head instead of the helmet we wouldn't be having this discussion.
The forces can all be recreated and modelled. the Energy levels can be calculated and all the other physical properties of your crash. They can analyze all the data points but none of it can prove the helmet saved your life You have made a faith based Analysis based on your emotional reaction to the visual and emotional cues. You are alive and your helmet was destroyed so it certainly is provable the helmet absorbed a lot of energy but you only have an opinion on what that represents in the scale of survival? It is also completely possible the helmet was in fact the tipping point on survival but that too is probably impossible to prove. The other minor point is some people die and other live under what appears to be the same conditions. What might that prove? It is this emotional faith in that Styrofoam, which makes this debate Impossible to treat as an engineering problem. The basic safety design of a bike helmet is a 2 KG head form dropped from 6 feet. That is about the same energy level of tripping on the sidewalk except we often sit higher than that.
The energy of that simple fall is still pretty high but it certainly is not designed to provide significant protection at much higher energies. ( note for the non physicists. At 60 kph the drop speed is the same if you were track standing. At 60 if your head stops suddenly you are dead. So there better be a lot of deceleration before you hit anything immovable with your head. At 60kph the vertical fall is the design parameters of your helmet but the forward momentum is only being absorbed by your head skipping along the road surface while your skin slows you down. That is what a bike helmet is designed for. Protect your skull from a 6 foot fall and protect your scalp from the road abrasions until you stop. Seems like a good reason to wear a helmet, so I do, and I am really glad your helmut might have saved your life. For you there is no debate but the curiosity in me wants more understanding of these dynamics.