A Construction Truck Front Tandem Suspension with One Driving Axle

This paper describes the design requirements and our solutions for a heavy-duty tandem steering axle suspension, and the related special 8x6 construction truck chassis. By restricting the tandem axle load equalization to the maximum legal load range only, it was possible to design a suspension using individual axle mountings. This mounting achieved substantial benefits in weight, performance, cost, and development time over an equalizing beam type suspension as applied to a vehicle front end. In addition, the design incorporates a variable front axle load distribution feature, which increases empty vehicle and off-highway mobility by allowing a temporary biasing of weight to the front driving axle. Consequently, the concept is particularly well suited to a front tandem with only one axle driving. Also described are experimental automatic control variations, unsuccessful and otherwise, that led to the final development.