I am skeptical, for the following reason. I did a ride with a friend last year, where I went as slow as I could, but he kept falling behind. This was especially pronounced on downhills where I didn't even pedal but kept rolling away from him, even though he was pedaling. After the ride, I gave his front wheel a spin, and it only spun for a second or two before slowing to a halt. He had WAY too much preload on his wheel bearings. There are many reasons one bike might require more effort to achieve the same speed, so it seems presumptuous to ascribe it to one's favorite variable.