With the aid of these miracle computers I'm gonna try and explain some helmet info. In the picture below you can switch between two head positions and see an example of the flow pattern. Now play with them briefly and decide which one is best. ........ The answer is that in a direct headwind the head down is a good bit better but if you average the drag over a "0" to "7.5degree" range they end up almost identical. At a straight to 2.5 degree headwind the head down position has a drag of 6.079 while the head up position has a drag of 6.260. Thats about the difference a real fast front wheel can make. At 7.5 degrees the increased surface area starts to work against you and the drag goes up considerably. I suppose I'm making a case here that you would really need to watch your wind angles to know how to hold your head, of course you can't buy one of these helmets anyway but even the standard helmets have reacted the same way. Why does this happen? Notice that with the head up position the air flows all the way down the back in a pretty undisturbed line. This is actually not good because the air is dragging against your body the whole way. With the head down position the air that goes over the tail breaks up and gets away from the rider. Humans don't work like airplanes in the air so we've started to learn to do some different things for more efficient air flow.