Chassis

The chassis or frame of a truck is commonly constructed mainly of two beams, and several crossmembers. A truck chassis consists of two parallel straight C-shaped beams, or in some cases stepped or tapered beams, these held together by crossmembers. In most instances, gussets help attach the crossmembers to the beams. The "C-shape" of the beams has a middle vertical and longer side, and a short horizontal flange at each end; the length of the beams is variable. The chassis is usually made of steel, but can be made (whole or in part) of aluminium for a lighter weight. The integrity of the chemical composition (carbon, molybdenum, etc.) and structure of the beams is of uttermost importance to its strength, and to help prevent cracking or breaking of beams, and to help maintain rigidity and flexibility of the frame, welding, drilling and other types of modifications should not be performed by unlicenced persons. The chassis is the main structure of the truck, and the other parts attach to it. A tow bar may be found attached at one or both ends.