Our research and testing reveals an interesting counterpoint.

We tested our bicycles using the Formula 1 wind tunnel in Nevers Magny-Cours.

One of the most important features of this testing facility is that it has a moving floor which allows wheels to roll as they would on a road while cycling. When the air created by a moving bicycle comes in contact with the air generated by the rotating rear wheel, our testing has demonstrated that if the wheel and tire are too close to the frame, this converging air turbulence actually slows the wheel of the bicycle.

Opening up the space between the seat-tube and the tire allows the convergence and turbulence to dissipate and have less effect on wheel speed.