This paper documents the development of aerodynamic apparel for the Tour de France individual time trial (TT), the Olympic TT, and track cycling races. A wind tunnel and metric balance were used to measure the drag force (Fd) and wind tunnel air velocity on cylinders, limb models, and live cyclists clad in samples or suits sewn with one or more of 200 stretch fabrics. A concurrent measurement of model dimensions and frontal areas provided the non‐dimensional drag coefficient (Cd) and Reynolds Numbers (Re) that characterized the ability of the various fabrics and suits to reduce frictional drag and induce a drag crisis (DC) or premature flow transition. DC defines a critical air velocity over the body segments at which the airflow transitions from laminar to turbulent, yielding a smaller wake behind the body segment and a corresponding decrease in Fd. A number of fabrics triggered DC on cylinders and limb segments, reducing cylinder and limb Cd by over 40 per cent. Several methods of lowering the Fd of cyc...