Body Frame Integral

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Body frame integral (BFI) is a methodology for manufacturing within the automotive industry. It has become the main technique for chassis assembly for most vehicles except trucks and large sport utility vehicles, replacing the traditional approach of body-on-frame (BOF).

BOF utilizes an independent frame that is used to connect the suspension to the body frame. The main advantage of this is that soft mounts are used to reasonably isolate the body from the vibrations endured by both the frame and the suspension system. BFI was developed for the main purposes of reducing weight and drag, as well as lowering the center of gravity. Front end cradles are still used in BFI, which allows soft mounts to be implemented in the engine compartment. However, most rear ends are hard mounted, but technological advancements allow the associated effects of noise, vibration, and harshness to be suitably managed.

[edit] Advantages and disadvantages

Advantages Effects Disadvantages Effects
Fewer parts and less weight Better fuel efficiency Difficult components to integrate Harder to assemble and repair


Lower center of Gravity Less likely to roll vehicle Noise, Vibration, and Harshness increased Customer satisfaction issue
Less drag Better fuel efficiency Passengers do not sit as high Customer satisfaction issue
Better wheel clearance Allows diverse selection Less durable than BOF; cab and bed need to be connected Most trucks not applicable for BFI

[edit] See also