There are many people who use ‘chassis’ and frame interchangeably. The differences between them are expressly clear. Once you learn the unique functions of each, you will never consider a chassis the same as a frame.
A chassis is different from a frame. While a frame bears some parts of the car, it is not exclusive. A chassis is exclusive in its support of the car, and there would be no car without a chassis.
In this article, I will describe what a chassis is and the differences between a chassis and a frame. I have also provided details on the two types of chassis. To conclude, I will talk about the signs of a damaged chassis and how to maintain it.
What Is Considered the Chassis?
The chassis is the framework of a car. You can liken it to the skeletal frames of humans and animals as they share a similar function. The power train and body of the car all rest on the chassis.
Without the chassis, the engine, suspension system, brake system, transmission, drive train, and wheel supports will have nothing to attach to. It supplies the strength required to support all these components and the payload of the car. A car is rigid because of the chassis.
Besides the structural and load-bearing functions of the chassis, it also limits the levels of vibrations, harshness, and noise throughout your car. You can sit in your car safely and drive in comfort because of the reliability of the car’s chassis.
Is a Chassis the Same as a Frame?
Although both are supporting structures, there is a difference in the parts of the car that they support. The frame is the primary part of the chassis to which all other parts of the chassis are attached.
The frame also handles the initial shock from collisions and manages the torque generated by the engine and transmission. In reality, the engine of the car, steering system, brake system, fuel tank, suspension system, and rear axle rest on the frame.
The chassis then bears the frame and all the parts it connects to. In this way, the chassis is responsible for all the parts of the car involved in its movement, ease on rough surfaces, and direction (the mechanical parts).
The chassis has a simple design, and it is made with the car’s movement in mind. The frame’s design takes into consideration the fact that it will bear all other parts, as well as the body. Types of frames include Off set frame, Perimeter frame, X-type frame, Ladder-type frame, etc.
What Are the Two Types of Chassis?
Carbon steel, carbon fiber, and aluminum are the materials that make up all types of chassis. There may be many types of chassis designs available, but they all fall under two main types, namely:
- The conventional or frame-full chassis
It is also called the body-on-frame chassis because its ladder frame attaches the body of the car to it. It has a solid build, and it comes out of an accident with minimal or zero damage.
You can see this type of chassis in buses, SUVs, trucks, and other bigger cars. The BMW i3 and i8 are the only compact cars with this type of chassis.
- It has a simple design, and there is no stress with building or altering it.
- The parts that attach to it detach easily, and this aids repairs.
- It can carry a higher load and is stronger.
- Higher load capacity and strength.
- Since it sustains minor damages in accidents, it is easier to repair.
- It consumes more fuel because of its weight.
- Performance figures for cars with this chassis are low.
- The presence of some loose parts and frame joints increases vibrations.
- Car refinement and handling are lower.
- The unconventional or frameless chassis
There is no ladder frame to attach the body here. Instead, the frame and the body are composed as one unit. You might also know it as a unit-body chassis, an integral chassis, or a monocoque chassis. Sedans, saloon cars, hatchbacks, and other modern cars have this type of chassis.
- It is lighter and more rigid, resulting in better car handling and refinement.
- There is less rattling.
- Cars with this type of chassis use less fuel.
- It does not fare well in accidents.
- It has a lower load-bearing capacity.
How Do You Know a Chassis Is Damaged?
Unless the damage is to an unconventional chassis, it’s easy to miss the signs of damage to an otherwise “hidden” structure. Even the slightest damage can produce obvious signs if you know what to look out for. Here are a few to note:
- Tears that wear out fast indicate issues with the wheel alignment and suspension. One function of the suspension is to maintain friction between the tire and the road. If your tires also wear out in an uneven pattern, it suggests a damaged chassis.
- Strange noises are another sign of issues with the chassis. Pinpointing the source of strange sounds in a car can be like searching for a needle in a haystack. However, combining the strange sounds with other specific signs of chassis damage helps narrow it down.
- When your car becomes difficult to handle on the road, check your chassis. Remember that the steering system is attached to it, and any damage to the chassis could compromise it.
- Decreasing fuel efficiency also suggests a chassis problem. One of the mechanical parts that rest on the chassis is the fuel tank. Once you have ruled out other potential causes of an increase in fuel consumption, look at the chassis.
Considering the importance of the chassis to the general structure and functioning of your car, you should maintain it properly. Inspect and lubricate your chassis at least every six months. You can do this alone or add it in with other checks when you visit your mechanic.
Strive to keep your chassis as clean as possible. Its location under the car sets it up for easy accumulation of mud and dirt. A simple wash with water and a sponge at home is enough.