Commentary, further detail and references for Effect of Variable CdA on Combined CdA and Crr Solutions in Field Testing. Each note is addressed by name so it can be cited from anywhere in the Knowledgebase. Working draft, 2026-10-06.
Both parts of the format are also described in writing, in the home testing guide published by Silca. For the climb: "The key here is to do a really slow effort, a medium effort, and another around your threshold or even higher." For the coast-downs: "You pick a start and end point and hit the start point at three different speeds."
Silca (2023). Aero Testing at Home - A Step by Step Guide. 7 April 2023. silca.cc
Referenced from: VE model
Grappe (2009) is one cyclist in a static position, measured from 15 to 100 km/h in 5 km/h steps.
Brown et al. (2023) is a mannequin, bare and in a skinsuit, measured at six turbulence intensities from 1.4 to 9.1%. The curves used on the page are those of its Fig. 21 at a turbulence intensity of 2.5%, which start at 27 km/h.
Both sets are discussed in The Case for a Variable CdA in Cycling, whose notes list the Grappe points.
Grappe, F. (2009), Cyclisme et optimisation de la performance, 2nd ed., De Boeck; data as reproduced in Debraux, Grappe, Manolova & Bertucci (2011), Sports Biomechanics 10(3), 197–218. doi.org/10.1080/14763141.2011.592209
Brown C, Burton D, Crouch T, Thompson MC (2023). The influence of turbulence on cycling aerodynamics. Journal of Wind Engineering & Industrial Aerodynamics 242, 105575. doi.org/10.1016/j.jweia.2023.105575
Referenced from: CdA and Crr errors