Farmers experience whole-body vibrations when they drive tractors. Among the
various factors that influence the vibrations to which the driver is exposed are terrain
roughness, tractor speed, tire type and pressure, rear axle width, and tractor seat height
above the ground. In this paper the influence of tractor seat height above the ground on the
lateral vibrations to which the tractor driver is exposed is studied by means of a
geometrical and an experimental analysis. Both analyses show that: (i) lateral vibrations
experienced by a tractor driver increase linearly with tractor-seat height above the ground;
(ii) lateral vibrations to which the tractor driver is exposed can equal or exceed vertical
vibrations; (iii) in medium-size tractors, a feasible 30 cm reduction in the height of the
tractor seat, which represents only 15% of its current height, will reduce the lateral
vibrations by around 20%; and (iv) vertical vibrations are scarcely influenced by
tractor-seat height above the ground. The results suggest that manufacturers could increase
the comfort of tractors by lowering tractor-seat height above the ground, which will reduce
lateral vibrations.
