A typical pick-up truck fuel tank ranges in size from 20 to 40 gallons. Larger trucks, such as the Ford Super Duty line, have bigger tanks.
Older trucks used tanks with smaller capacities. For instance, early 1950s GMC trucks used tanks that only held 18 gallons. Newer trucks have a larger focus on fuel economy and more miles per tank, which ultimately leads to larger tank capacities.
The location of gas tanks have also changed. Earlier trucks from the 1950s had the tanks mounted to the rear of the cab, which lead to a hazardous environment for the driver. The newer location positions the tank further away from the cabin, making the vehicle safer.