Originally Posted by
BarracksSi
My speed varied by nearly ten mph even with the same perceived effort thanks to whether I had the wind at my back or in my face.
This; my commute includes about 3/4 mile of school zone with no curb and narrow lanes, so I like to keep at least 15mph through there, without going too much over 20. It's a slight downslope, so with a tailwind, 24 isn't hard, but with a headwind, 12 can feel like 20.