bodyonframe

Body-on-frame (BOF) is a vehicle construction method in which a separate rigid frame supports the vehicle’s drivetrain, suspension mounting points, and chassis loads, while the passenger cabin and exterior body are built independently and later mounted onto the frame. The frame—often a ladder or box-type frame—provides structural rigidity and acts as the primary load-bearing element. The body is attached to the frame at multiple mounting points, with bushings and fasteners that absorb vibration but allow some independent movement. In unibody designs, by contrast, the body and frame are integrated into a single shell that carries most of the loads.

BOF has long been favored for trucks, larger SUVs, and rugged, off-road capable vehicles because it tolerates heavy use, torsional stress, and off-road impacts well, and it facilitates repairs or upgrades in the field. It also supports higher towing capacities and easier replacement of damaged sections. The downsides include generally greater weight, reduced energy efficiency, and sometimes a rougher ride and lower interior packaging efficiency compared with unibody designs. In modern passenger cars, unibody construction has become dominant, while BOF remains common in pickup trucks and many full-size SUVs and off-road vehicles. Examples of vehicles built on a body-on-frame chassis include the Ford F-Series trucks, Chevrolet Silverado and GMC Sierra, Toyota Land Cruiser, Toyota 4Runner, Ford Expedition, Jeep Wrangler, Nissan Armada, and similar platforms.