Originally posted by velocipedio
In fact, there is a mathematical proof of this. I remember it from a college physics class many years ago, although I don't recall exactly what it was now, after about 20 years of hard riding.
I've noticed that even when riding with a tailwind, I eventually crank it up to a speed that exceeds my tailwind, giving me, in effect, a minor wind resistance.
When riding into a headwind, I've never experienced a reciprocal effect.