To bridge the gap between the pickup line and the much larger medium-duty F-650/F-750, Ford introduced the F-450 and F-550 variants of the Super Duty; with an available GVWR from 17,950 to 19,500 lb, it pushes the Super Duty into the Class 5 truck market. Available only as a chassis cab, both versions were fitted with dual rear wheels.
While largely aimed at fleet buyers, F-450 and F-550 models were configurable in XL, XLT, and Lariat trim levels available to Super Duty pickup buyers. The sole gasoline engine was the 6.8 L V10, while the 7.3 L Power Stroke was the diesel option; in 2003, this was replaced by the 6.0 L Power Stroke.
In 2005, the F-450 and F-550 received further updates to the exterior than the rest of the Super Duty line, with an extended front bumper and front fenders; the F-550 received a “wide-track” front axle to sharpen its turning radius.