The design and optimization of fork–pin compression coupling in front motorbike suspensions

The fundamental goal of this work is to determine a mathematical model useful to calculate the tensile state in the fork–pin compression-fit couplings of front motorbike suspensions. The second goal is to update an original software (Fork Design©Design©) which may be used in order to design and to verify this type of coupling. The mathematical formulas used by the program are based on the thick wall theory appropriately modified with the newly developed model. The new formulas were determined for the forks, which have an asymmetric tangential stiffness, by performing several finite element analyses with different geometrical and stiffness parameters. At this time, the mathematical model has been verified for all the Paioli Meccanica S.p.A. fork–pin couplings and thus it is useful to compute analytically their tensile state. Anyway, the authors think that the findings may be extended and applied to other fork–pin couplings. Finally, a specific software has been updated with the aim to perform accurately the design and verification of the coupling.