A trailer hitch for a passenger car or light truck is a permanent or semi-permanent installation mounted to the frame of the vehicle. Some hitches have a fixed tongue to which a ball connector mounts. Others end in a square receiver that accepts a matching mount for the ball.
Hitch receivers are commonly available in two sizes, 1-1/4 inches and 2 inches square. The hitches are rated by their maximum towing capacity. Class I hitches have a 2,000-lb capacity. Receiver-style hitches are available up to Class V, for loads in excess of 10,000 pounds. Class V hitches typically have a 2-1/2 inch receiver. Bicycle racks that slide into the receiver are also available.
The hitch mounts to the frame and has a receiver at its center, which sits just below the vehicle's rear bumper. All of the tubing on a square hitch has a square cross-section. Square-tubing hitches are available in Class I through Class V.
Round-tube hitches are available in Class I through V. This style also has a square receiver that sits below the rear bumper, but the tubing that connects the receiver to the frame is round instead of square and bends along the length are smoothly contoured instead of angular. Round-tube hitches are lighter than square-tube hitches of the same capacity, and are considered more attractive because they are less angular.
