The towing capacity for a 2015 model year Ford F-150 regular cab 4x4 pickup is between 7,500 and 11,900 pounds, depending on the truck's options. Optional features that impact the towing capacity are the engine type, the wheelbase length and the axle ratio.
The best axle ratio for towing on all models is 3.73. With the twin independent variable camshaft timing engines, the 3.5 liter six-cylinder performed best with a 122.4-inch wheelbase by towing 7,500 pounds.
The 5.0 liter eight-cylinder version towed its best, 11,100 pounds, with a 141.1 inch-wheelbase.
The twin turbo EcoBoost engines are both six-cylinder designs, with the 2.7 liter towing 8,400 pounds with either wheelbase, and the 3.5 liter pulling the most weight for a 4x4 F-150 at 11,900 pounds on a 141.1-inch wheelbase.