Title: An empirical model for determining the radial force-deflection characteristics of off-road bicycle tyres

Authors: D.F. Moore, E.L. Wang, M.L. Hull

Addresses: Research Assistant, Department of Mechanical Engineering, University of California, Davis, CA, USA. ' Assistant Professor, Department of Mechanical Engineering, University of Nevada, Reno, NV, USA. ' Professor, Department of Mechanical Engineering, University of California, Davis, CA 95616, USA

Abstract: To characterize tyre stiffness on uneven terrain for use in a mathematical model of an off-road bicycle, this study developed an empirical model of tyre radial load-deflection behaviour. To provide data for the tyre model, load-deflection was measured for a single tyre compressed on a variety of semicircular surfaces spanning radii 58.4 cm convex to 58.4 cm concave. A power equation which included two independent data for both concave and convex surfaces - tyre deflection and surface radius - and six coefficients was found to fit the experimental data for both surfaces. However, the coefficients were dependent on the type of surface (i.e. either convex or concave). The concave surface model predicted the force to within a maximum relative error of 4.2% for all concave surfaces tested while the maximum relative error for the convex surfaces was bounded by 13.5%. With the accuracy of the tyre model established, it can now be incorporated into a bicycle/rider system model.

Keywords: tyre stiffness; uneven terrain; mathematical modelling; off-road bicycles; modelling; radial deflections; radial loads; radial forces; bicycle tyres; tyre modelling; tyre deflection; surface radius.

DOI: 10.1504/IJVD.1996.061972

International Journal of Vehicle Design, 1996 Vol.17 No.4, pp.471 - 482

Published online: 28 May 2014 *

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