Variation of the drafting effect on the trailing rider for different numbers of riders in a cycling group

Abstract

The technique of following another rider to reduce aerodynamic drag (drafting) is a basic tactic in cycling. This study clarifies the trailing rider’s drafting effect for different numbers of riders and relative positions in the traveling group. Wind tunnel experiments were conducted with a static mannequin as the subject measured. Measurements were made with a floor-mounted six-component force balance. Athletes sat on bicycles mounted on bicycle stands and provided the drafting effect; experiments were conducted for riding groups of two riders (2R) and four riders (4R). The aerodynamic drag of the most trailing rider (i.e. mannequin) was measured for a wind speed of 16.67 m/s and different relative spatial positions (a longitudinal distance of 0–0.75 m and lateral distance of 0–0.90 m) to the rider ahead. When the approximate tandem arrangement had a lateral distance of 0–0.25 m, the aerodynamic drag increased with the longitudinal distance in both 2R and 4R. However, the increase was much smaller in the 4R than in the 2R. In the range of lateral distance in which there is a drafting effect, the drafting effect was stronger in the 4R than in the 2R. It is thought that the fourth position without tight separation can achieve a drafting effect comparable to that of the second position with tight separation.