Chassis is a term that comes from the French word chassis. Although it is a concept that is used frequently, many times there are misunderstandings with its meaning or scope, since it is often confused with other structures.

It’s called a chassis, or chassis (with an accent on the I), to the frame that supports the bodywork of a car. From this definition, we can already see that the chassis and the body are different things.


The chassis supports the body.

What is the chassis

It can be said that the chassis is the skeleton vehicle. It is an internal component that integrates and supports the engine, transmission and suspension, among other mechanisms and systems essential for the functioning of this means of locomotion.

The stability and robustness of a car largely depend on the chassis. It is important to bear in mind that it enables the assembly of the rest of the parts and devices that make up the car.

The chassis generally consists of beams Y tubes of different calibers according to their function. The most used materials are metals Y alloys.

Classification according to type

There are two main types of chassis: the independent chassis and the monocoque or self-supporting chassis. In the case of the independent chassis, it can be frame or from central tunnel.

The frame independent chassis It is made up of transverse beams (known as crossbars) and longitudinal beams (the stringers). All parts and mechanical assemblies of the vehicle are attached to it in various ways. It should be noted that this frame – used by the trucks, the collective or buses and the all terrain– many times it is also referred to as a chassis.


In some cases, chassis is used as a synonym for frame.

The center tunnel chassis, meanwhile, it presents a rectangular structure of tubes, to which the anchors of the suspensions. Therefore, it lacks the cross members and stringers that the frame chassis presents.

The monocoque chassis, for its part, is characterized by its mode of manufacture. This chassis is built on a single piece: the various mechanisms and structures, including the bodywork, are joined together by appealing to welds. This chassis is used in most of the automobiles or cars.

Differences between chassis, body, frame and platform

We already indicated that the chassis is the internal structure of a car that gives it medium to the bodywork and used for the integration of the other components of the vehicle. The idea of frame It can also refer to this kind of frame, although it usually refers specifically to a part of the chassis (specifically to the structure formed by the cross members and the side members).

According to the dictionary of the Royal Spanish Academy (RAE), the notion of platform can be used to refer to the chassis or the rack. Another definition, instead, speaks of the platform as the set formed by the base, the steering, the axles, the suspension and the engine compartment. This set can be shared by different brands in different models.

Refering to bodywork, it is the part of the car that is located on the chassis, covering the motor and providing the interior space for the transfer of passengers and luggage. The shape of the body makes a car can be a sedan, coupe, three-door, five-door or station wagon, for example.