Recent improvements and design formulae applied to front motorbike suspensions

The aim of this paper is to provide a methodology useful for the structural design and optimization of front motorbike suspensions. Two different types of shaft–hub couplings are used to assembly the whole suspension: interference fit couplings and bolted joints. Some mathematical models and engineering design formulae are proposed in order to calculate the tensile state and the fundamental design parameters of the main couplings, such as, for example, the fork–steering shaft and the leg–wheel pin couplings. Both experimental tests (based on the Design of Experiment approach) and numerical analyses (based on the Finite Elements Method) have been carried out to obtain the proposed results. All the research findings culminate in an innovative software (Front Suspension Design©) which is useful to design and to verify the whole front motorbike suspension, by applying correct and effective results, obtained for different geometries and materials combinations.