What Is A Chassis, And What Are Its Types?

What Is An Automobile Chassis?

Chassis is the vehicle’s main support structure, also known as the ‘Frame.’ It bears all the stresses on the vehicle in both static and dynamic conditions. In a vehicle, it is analogous to the skeleton of a living organism. The origin of the word Chassis lies in the French language. Whether it is a two-wheeler or a car, or a truck, every vehicle has a chassis-frame. However, its form, obviously, varies with the vehicle type.

The Chassis has the following functions. It:

Supports or bears the load of the vehicle body.
Provide the space and mounting location for various aggregates of vehicle.
Supports the weight of various systems of the vehicle such as engine, transmission etc.
Supports a load of passengers as well as the luggage.
Withstands the stresses arising due to bad road conditions.
Withstands stresses during braking and acceleration of the vehicle.

Various types of Frames:

Depending upon the application, some of the main types are as below:

Ladder Frame:

See a typical ladder chassis in the image below:

Ladder Type (Courtesy: SAE International)

Applications of Ladder Frame:

Heavy commercial vehicles such as trucks and buses mainly use the ladder-type chassis structure. However, some light commercial vehicles like pickup trucks also use the ladder-type.

Tubular Frame:

A typical tubular frame in the image below:

Tubular-chassis — Tubular Chassis (Courtesy: DTM Power)

Applications of Tubular Type:

Some racing vehicles and All-Terrain vehicles use tubular frame designs.

Monocoque:

See a typical monocoque chassis in the image below:

Applications of Monocoque:

Almost all high-performance cars use a monocoque design.

What is Rolling Chassis?

It is the type in ‘ready to run’ condition. It means that such a frame has an engine, transmission, axles, tires, and all the other systems attached to it that are mandatory to run a vehicle (collectively called ‘Running gear’). Hence, you could legally drive it on the road.

Manufacturers generally use the term “rolling” to refer to the trucks or buses they transport to the vehicle bodybuilder. It is where they build the body on them.

Rolling chassis — A typical Rolling Chassis (Courtesy: Tata Motors)

Watch A Chassis-Frame In Action Here:

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