In the absence of special measures, the spring characteristics of the leaf spring is linear. The relationship between the deflection f and the load L at the end of a cantilever beam is known from strength of materials and is given as shown in the figure.
In order to ensure the effective guidance of the axle leaf spring, the width b and the thickness s can be varied for the definition of the leaf spring rigidity c only within certain limits. Usually relatively large spring lengths are necessary in practice. Truck leaf springs are up to 1800 mm long.
Since the bending force correspondingly decreases from the spring center to the ends, spring leaves of varying length are arranged in layers such that a high and uniform degree of material utilization is achieved.