This document specifies a test method for determining the transverse flexibility (troughability) of a conveyor belt, expressed as a ratio, F/L. The method is not suitable or valid for light conveyor belts as described in ISO 21183-1. NOTE The transverse flexibility determined by the method described in this document is only indirectly associated with the inverse of flexural modulus as specified in ISO 178. Nor does it take into consideration the differences in flexibility as exhibited by three-point and four-point bending, which takes account of the flexural strain and the thickness of the test piece.