A semi-trailer is a type of trailer designed to be partially supported by a tractor unit (also known as a prime mover or truck tractor). The front part of the semi-trailer rests on a fifth wheel (or kingpin) mounted on the tractor, while the rear is supported by its own wheels.
Structural:
Semi-trailers have only one axle or a set of axles at the rear, with the front resting on the tractor's fifth wheel. They are designed to share part of the load with the tractor unit.
Tractor Unit Involvement:
The tractor unit bears a significant portion of the semi-trailer's weight, through the fifth wheel connection. It also provides the propulsion and braking forces needed for the combined vehicle.
Applications:
Semi-trailers are commonly used for long-distance transportation of heavy loads, such as containers, bulk cargo, and livestock. They are efficient for highway travel due to their ability to distribute weight evenly.
A full trailer, also called a full-trailer truck or a straight truck, is a trailer that is connected to a tractor unit using a hitch or drawbar. The entire weight of the trailer is borne by its own wheels, and the tractor unit provides only the pulling force.
Structural:
Full trailers have two or more axles and are self-supporting. They carry their entire load without relying on the tractor unit for weight support.
Tractor Unit Involvement:
The tractor unit does not bear any of the weight of the full trailer. It simply provides the pulling force and braking capabilities.
Applications:
Full trailers are used in various applications, including short-haul transportation, construction sites, and delivery services. They are also suitable for use in areas with tight turns or limited space.
