[toast0]

I can hit 45 mph going down hill on my 1980 road bike... but that's just balance, carrying enough potential energy, being too stupid to slow down to a reasonable speed, and having hills that I have to walk the bike up most of the time. There's some skill and physical conditioning there, but not a whole lot; at that speed, there's a lot of instant feedback on form, which helps encourage one to get low and tight.

I think if we're talking about how fast you can get your bike to go, flat land, still air is implied. I don't have a lot of those conditions to try, but I'm happy to cruise around 15, and maybe push it to 20 if I don't need to save my energy for a nearby hill.