why is a fifth wheel called a fifth wheel
Fifth-wheel coupling The term fifth wheel comes from a similar coupling used on four-wheel horse-drawn carriages and wagons. The device allowed the front axle assembly to pivot in the horizontal plane, to facilitate turning. Basically a wheel was placed on the rear frame section of the truck, which back then only had four wheels; this wheel that was placed on the frame was the "fifth wheel", hence the name. The trailer needed to be raised so that the trailer's pin would be able to drop into the central hole of the fifth wheel.
Front-wheel drive Front-wheel drive (FWD) is a form of engine and transmission layout used in motor vehicles, where the engine drives the front wheels only. Most modern front-wheel-drive vehicles feature a transverse engine, rather than the conventional longitudinal engine arrangement generally found in rear-wheel-drive and four-wheel drive vehicles.