Several experimental techniques of obtaining data such as retraction, folding angles, and outer filament angles as functions of the cording twist are discussed in detail. It is shown that realistic results are obtained only when cords are individually made and that measurements of length and angle made during the twisting or untwisting of a short length of cord (e.g., as in a twist tester) are meaningless. The distortion of the shape of the ply cross-section is discussed and illustrated for two-, three- and seven-fold cords. These experimental aspects are taken into account when comparing the results with those calculated on the basis of Treloar’s theory of the geometry of multi-ply yarns. The best agreement between the calculated and observed cord retractions is shown to occur with seven-fold cords, where the distortion of the ply cross-section is the least. This is also true for the angles which the ply axis and outer filament make with the cord axis, though the agreement throughout in this case is not so good.