This work deals with the development of an analytical model, which allows to describe the tensile state arising in single-disc motorcycle suspensions, during the brake. Stress and strain trends are computed as functions of some key parameters of the motorcycle (mass and centre of gravity location) and of the fork (lengths and diameters). A portal frame loaded out of its plane represents the suspension geometry, whose axisymmetric elements represent the pillars (legs) and the wheel pin is the transverse beam. Each of the three elements has material and inertia parameters variable along its axis depending on the actual mechanical properties of the component. Finally, the stress field of several fork models has been investigated both via FEA and via in field tests, in order to support the effectiveness of the proposed model.