Post: Truck classification

Trucks can be divided into inline trucks and articulated trucks. Inline trucks are trucks with all axles mounted on a single frame. Articulated vehicles are vehicles made up of two or more independent frames connected by suitable couplings. A truck tractor is a motor vehicle used primarily for towing a truck trailer for carrying part of its weight and load. A semitrailer is a truck trailer equipped with one or more axles, constructed so that its ends and most of its own weight and the weight of its load rest on the truck tractor. In contrast, a full trailer is constructed so that all of its own weight and the weight of its load rest on its own wheels.
A type of vehicle called a fifth wheel is used to connect the truck tractor to the semitrailer and allows articulation between the units. It usually consists of a lower half, consisting of a trunnion (pivot assembly) plate and locking mechanism, mounted on the truck tractor for connection with a kingpin mounted on the semitrailer. Semi-trailers can be converted to trailer bodies (auxiliary Axle assemblies with tractor lower halves, drawbars and other specialized parts.
A heavy truck axle assembly may consist of two or more axles, any of which can be a live axle. Usually, they are spaced so that the distance between the axle centers does not exceed 1.5 times the total diameter of the wheels and tires. If the distance between the axles is greater, the assembly is called an extended tandem.