Another disadvantage of the leaf spring involves dry friction which occurs both in the suspension as well as between the leaves of the multi layer leaf spring (see figure). This dry friction has an unfavorable influence on the suspension characteristics.
The disadvantages can be compensated to a certain extent by the use of shackles instead of sliding shoes in the suspension or by the introduction of plastic layers between the spring leaves.
The use of a small number of leaves in the spring particularly influences the reduction of frictional forces positively. This is possible, not by the use of additional spring leaves but by the use of stronger leaves capable of withstanding higher bending forces at the spring centre. This leads to a higher degree of utilisation of material.
The bending stress along the length of the leaf is constant, if the spring halves indicate a parabolic profile in the longitudinal section. Leaf springs with such leaves are called parabolic springs.