I took the speedo meter off my mountain bike when I did endurance races, it just made me sad, and my commuter has never had one. Math says I spin out in the low 20s on the commuter. The calculator says I average about 16mph from unlocking the chain to opening my front door on my commute.

In other places? Descending Laramie Pass I was in the mid 50s. There was a 2mph difference between full-crouch-chin-touching-the-stem and just being low in the drops. Took me 45 minutes to climb that pile of rock, and less than 10 minutes to get back down it. In the flattest-of-the-flat in Oklahoma, I could usually break 40 on the down-hill-and-down-wind side of the only hill in town, where the road went over the train tracks. But only when the wind was 20knots or better. On flat-with-no-wind, I can hit 35, but not stay there long enough to make the effort worthwhile. And I've seen 750knots ground speed one day riding the jetstream, and mach 1.05 one afternoon in California, but neither of those involved wheels touching ground, and both were burning hydrocarbons.