How much slower is my bike?

[aarondeutchman]

That’s actually not true that a headwind is the same as riding faster.

This post explains it:

Headwind vs. Speed Calculation, big difference in watts

Hoping someone can help my intuition around speed in different wind conditions. On Bike calculator, I’ve taken two cases, 20km/h speed + 20km/h headwind, vs. 40km/h speed + 0 km/h head wind. Since at 40km/h most of the watts is fighting aero drag, I would have thought these would require similar watts? But it shows 186 W (manageable for many) vs. 373 W (big watts) I would have assumed that these would be much closer, since in both cases you’re (mostly) fighting 40km/h of air-drag, irrespective…