A vehicle has a chassis (11) and at least one axle (12, 13) suspended from the chassis for vertical and roll movement relative to the chassis. The axle is mounted on the chassis via a first pivotal mounting means in the form of an upper pair of arms (12a, 13a) which is pivoted on the chassis for vertical pivoting movement relative thereto and which carry an axle support (15, 16) on which the axle (12, 13) is free to pivot in the roll mode. A first damping means (19) acts between the chassis (11) and the first pivotal mounting means (12a, 13a) to control vertical movement of the axle relative to the chassis, and a second damping means acts between the first pivotal mounting means (12a, 13a) and the axle (12, 13) to provide independent control of the roll movement of the axle relative to the chassis. A second lower pair of pivoting arms (12b, 13b) also connect the axle (12, 13) to the chassis to control fore and aft movement of the axle relative to the chassis. When both axles are mounted on the chassis using the above upper (12a, 13a) and lower (12b, 13b) pairs of arms the line of action of the forces (F1-F4) applied to the chassis (11) by the upper arms (12a, 13a) at one end of the chassis may be substantially aligned with the line of action of the forces applied to the chassis by the lower arms (12b, 13b) at the other end of the chassis to reduce and tendency for the chassis to be twisted by these forces.