[prmoustache]

Aero also helps at 25 or 30kph.

It is quite easy to check out actually on a road bike. Ride at a steady pace without pushing hard, hands on top, then put your hands in the hoods of the brake lever, elbows at 90° without pushing more, you will gain easily 1kph just by changing position. More if it is windy.

[newaccount74]

I assume the poster meant aerodynamic optimisation of the bike itself (eg. aero wheels, aero saddle post, etc).

Riding position obviously makes a huge difference.