In Reply To:
Back of the napkin calcs: So if a frontal area decrease of even two rectangles of 5mm x 50mm is possible by switching pedal systems, we have a frontal area decrease of 0.00025 m^2 or 0.045% of the frontal area of a 0.55 m^2 frontal area cyclist. Assuming Cd does not change as the pedal systems are seeing generally turbuent air at low speeds in the wake of the shoe (past flow separation of the shoe), this could decrease total system CdA by that same 0.045% or ~0.010 m^2 (of 0.24 m^2 system CdA).
Okay -- so in theory, if you held a shoe in tangential 30 mph flow, you could realize this frontal area decrease and thus the significant drag savings. The thing I don't know yet is if the pedal and cleat system actually sees this kind of a situation enough to garner this aerodynamic savings. Any flow visualization to share?
Is that a paper or cloth napkin? .045% of .24 is .0001, not .01.