Dually

A dually is a heavy-duty pickup truck rated for at least 1 ton, fitted with two wheels on each side of the rear axle (six wheels total) for higher towing capacity and lateral stability. In the US, a dually is generally required to tow fifth wheels and trailers above 14,000–16,000 lb (6.3–7.3 t).

Popular models: Ford F-350/F-450 DRW, Ram 3500 DRW, Chevrolet Silverado 3500HD DRW. Towing capacity: 30,000–37,000 lb (13.6–16.8 t) on the kingpin in gooseneck/fifth-wheel mode. The trade-off is a wider rear (2–4″ more than a standard pickup) — harder to park and won't fit a standard garage. European equivalents are tractor units or Iveco/MAN truck chassis with a custom box body.