One of the latest off-road, rear dump truck developments in the earthmoving industry is GMC Euclid Division’s R-X truck, an all-wheel drive vehicle capable of hauling pay-loads up to 105 tons, at speeds of 53 mph. The R-X truck incorporates many innovations new to off-road truck design. A hinged frame, pivot steering arrangement, and equal load distribution on the two drive axles provide exceptional tractive effort and maneuverability. It reduces tire scrubbing in turns, which has been a major contributor to excessive tire wear, and allows the use of smaller tires, which lowers load height. Also unique in the R-X truck design is the suspension system which features the use of a patented “A” frame axle mounting which maintains axle alignments while permitting oscillation against stacked rubber disc spring members.