Development of a Multi-directional Rating Test Method for Bicycle Stiffness

The methods for determining the bicycle frame stiffness exist in many forms. Because the measuring method is not standardized, each bicycle magazine or bicycle constructer uses his own test setup. This leads to a wide variety of setups; they differ in many aspects such as applied load, boundary conditions and frame deflection measurement. To clarify some misunderstandings in frame testing, a multi-directional rating test method for bicycle frame stiffness has been developed. Prior to testing the stiffness of different frames it is important to assess the confidence limits of the stiffness result. This includes (i) the contribution of the test bench due to its non-zero compliance, (ii) the influence of mounting the frame in the test bench with a certain preload, (iii) the errors related to the force-and displacement measurement and finally (iv) estimating the influence of experimenter This sensitivity analysis on the test bench already led to a better understanding of frame stiffness testing, and which minor modifications can lead to major differences in stiffness values.