Body-on-frame

Towards the beginning of international automobile assembly and construction, most manufacturers created rolling chassis consisting of a powertrain, suspension, steering column and a fuel tank that was then sent to a coachbuilder that added the body, interior and upholstery to the customers specific requests.

In contrast, unibody or monocoque designs, where panels within the body supported the car on its suspension, were developed by European manufacturers in the late 1920s with Budd USA (which had a number of large factories in Europe) and its technical know-how.

[3] in addition, modern creature comforts, luxury and power-assisted features, and extensive safety reinforcement of vehicles have all added substantial weight, the ability to offset this with unibody construction has proven advantageous.

The trend had started with cars like the Citroën Traction Avant (1934) and Opel Olympia (a General Motors design) introduced in 1935, and the short-lived, aborted Chrysler Airflow.

Mass-market manufacturers Ford, General Motors, and Chrysler are abandoning true body-on-frame SUVs, opting, when sales volume permits, for more efficient unibody construction.

A ladder frame
A 2007 Toyota Tundra chassis holding the vehicle's engine, drivetrain, suspension and wheels.
The BMW i3 electric car is one of the rare modern passenger cars with a separate body and frame design (2013).
A Model T chassis ready for its body
All steel chassis and all steel body
Body by Edward G Budd Manufacturing Company of Philadelphia for John and Horace Dodge [ 1 ]
Austin A40 Sports , ca 1951. Jensen Motors (of West Bromwich ) built the aluminium-on-ash bodies under contract and transported them to Austin's Longbridge plant for final assembly. [ 6 ]