Answer from aerodynamics professor and Project 96 and 1984 U.S. Olympic Team bike designer, Dr. Chester Kyle: We measured this in the General Motors Wind Tunnel in 1996, and on the track using the SRM crank dynamometers. The lead rider in a 4-man pace line uses about 2 to 3 percent less energy than they would if riding solo.
The team is going approx 60 kph and the following riders have about 4-7 cm between the rear wheel of the rider ahead and their own front wheel. That makes a difference.
It makes it more NASCAR-like, then. More speed and closer gaps increase the efficiency of the draft.
I'm sorry, I meant what does "nominally" mean in the sentence "I was told that the distance with single bikes (drafter can only get so close with both wheels in the way) the one pulling is only nominally affected by the one drafting"?
nominally = "in name only" in this sense, i.e. no practical effect.
