The effect of rider weight on rider-induced loads during common cycling situations.

Motivated by the desire to provide information useful in the design analysis of bicycle frames, the hypothesis tested was that a simple linear model would relate the maximum magnitudes of rider-induced loads to rider weight. Rider-induced loads are loads developed as a result of weight and muscular actions during pedalling. To test this hypothesis, five riders spanning a wide weight range rode a bicycle unrestrained on a treadmill. Dynamometers measured six components of pedal loads and five components of both seat and handlebar loads while riders rode three common cycling situations--seated cruising, seated climbing, and standing climbing. Average, average maximum, and average minimum values were computed for all load components and each was analyzed statistically. For all three test cases, the regression slope was significant for the force component normal to the pedal surface. Because the normal pedal force component has been shown previously to dominate frame stress at the point most likely to fatigue (Hull and Bolourchi, 1988, J. Strain. Anal. 23, 105-114), the results of this study should be useful in designing frames optimized for minimum weight and acceptable structural reliability.