An omni-directional wheel assembly for a vehicle that includes a wheel, at least one lower suspension link and an upper attachment joint. Both the at least one lower suspension link and the upper attachment joint are attachable to the vehicle. The wheel is able to rotate at 360°, to steer the vehicle, around a pivot line positioned by the at least one lower suspension link and the upper attachment joint once attached to the vehicle. A projection of the pivot line onto a vertical projection plane comprises a vertical axis passing through a contact point between the wheel and ground defining a caster angle with the vertical axis, where whatever the orientation of the projection plane, the omni-directional wheel assembly includes an adjustment means able to adjust the caster angle within a predetermined range.