with a 3 9 u00d7 0 28 construction core strand of 3 wires with each a diameter of 0 28 mm envelopped by 9 sheath wires with the same diameter and with a polyester filament with a cross section 0 4 mm in the weft was subjected to a crimping treatment according to the invention the fabric contained 0 64 cords per mm of fabric width and was incorporated in a conveyor belt of the st 1000 strength class the adjacent warp cords alternately had a z lay and an s lay the crimp deformation was continuously applied by running the fabric in the warp direction between a couple of toothed rollers the stiffness s per mm of fabric width was calculated with the formula s ei n mm 9810d 4 u00d7 n u00d7 n wherein d 0 28 mm n 12 and n 0 64 so the calculated stiffness value s was 463 n mm with a selected value of k 1 16 s kp 2 gave a value for p of 20 mm to obtain a suitable elongation of approximately 0 5 on the crimped fabric at 10 of the breaking load of the uncrimped fabric a crimp amplitude was selected.