In their second wind tunnel report (watch Part 1), ITV Cycling's Chris Boardman and Ned Boulting demonstrate how misunderstanding aerodynamic drag can have unexpected effects on the Tour.
Chris explains how drag not only affects team trials but also has implications for the general classification and how growing appreciation for aerodynamics is affecting the sport.
More Tour features
See the 2013 race route in detail
Follow ITV Cycling on Twitter