A suspension
system for the main frame of a large dump
truck having laterally spaced frame members (10) each associated with a wheel mounting hub (12) the
system comprising, for each hub (12), a hollow forward attachment arm (20) supported by a bearing block (21) having a longitudinal journal (23) and a transverse journal (22), the longitudinal journal (23) receiving the attachment arm (20) and the transverse journal (22) receiving the ends of a shaft rigidly secured to the frame members (10) and extending therebetween to define a cross member and a vertically compliant suspension strut comprising a cylinder (41) rigidly attached to a support (28) secured to the frame member (10) and receiving a
piston (40) attached to a rear extension (42) from the hub (12) via a bearing which allows each hub (12) to rotate about longitudinal and transverse axes relative to the respective frame member (10). Also disclosed is dump
truck body (B) having side walls (61), a floor (62) and an end wall (63), the floor (62) being reinforced by longitudinal reinforcing beams and by only one
transverse beam (72). The side walls (61) slope inwardly, the floor (62) slopes downwardly and forwardly and the width of the floor (62) increases towards the rear of the body (B).