Roadies don't care much about aerodynamics, most of the time they're drafting.  MTB riders aren't going fast enough to care.  Time trialists and sprinters care a lot.  At aboc, we don't pretend to know much about aerodynamics, we prefer to claim that the only way to tell if something is aerodynamic is to test it and that many things that look fast aren't necessarily so.

So, here's something that took me by surprise.  Pedaling makes very little difference to drag, at least within the confines of this test (~13m/s, ~45km/h).  Here's a paper on it.  Intuitively, it seems obvious that pedalling faster would add more drag to the bike. 

Pedaling cadence showed little effect on the measured aerodynamic drag, with only a 1% variation between test conditions. Thus, any desired pedaling cadence can be used for wind-tunnel testing.

The drag measured for a rider when pedaling is not influenced in a significant way by the speed of pedaling, in the 40-100-rpm range. The drag measured while the rider is pedaling turned out to be a little smaller than the average of measurements taken with the rider's feet stationary at various positions around the pedaling circle. We do not know the reason for this difference, but it is quite small. We conclude that it is valid to take wind-tunnel drag measurements with the rider pedaling anywhere in the 40-100-rpm range.

So there you go.  40rpm, 100rpm ... no big difference in drag.  Not what I would have thought!  Aerodynamics ...