There is a reason why different cars suffer varying levels of damage in an accident. Small cars generally get squashed to an ugly mess, while vehicles like trucks, SUVs and buses are seldom totally crushed. The reason for this is the vehicle chassis.
This is the rigid metallic frame or skeleton of the vehicle to which all the mechanical parts are attached. The chassis is the backbone of the vehicle, thus it gives strength and stability to the vehicle.
TYPES OF VEHICLE CHASSIS
There are two main types of vehicle chassis, which are described below.
BODY-ON-FRAME CHASSIS
This is also known as the conventional chassis or the frame-full chassis. In this type of vehicle chassis, the body is made as a separate unit, then joined with a ladder frame. It is used in trucks, SUVs and bigger vehicles. This chassis is often built so solidly that it sustains little or no damage in an accident.
ADVANTAGES
- Higher load capacity and strength
- Easier to repair after accidents
- The detachable bodywork allows for quicker, easier repairs
- Easier to design, build and modify
DISADVANTAGES
- The body tends to vibrate easily, and the overall vehicle handling and refinement is lower
- Performance figures are low and fuel consumption is higher due to the weight.
UNIBODY CHASSIS
This is also known as integral chassis, frameless chassis, monocoque chassis, unit-body chassis and nonconventional chassis. In this type of vehicle chassis, the ladder frame is absent. Instead, the body itself acts as the frame for the vehicle. It supports all the vehicle systems. This type of chassis is mostly used in hatchbacks and sedan/saloon cars.
ADVANTAGES
- Less rattles and squeaks
- Handling is better due to the higher body rigidity and weight
- Better fuel efficiency
DISADVANTAGES
- The load-bearing capacity is much lower
- It suffers greatly in accidents
The unibody chassis is mostly used in modern vehicle types and is more suited for everyday, luxury and sort-oriented vehicles.
On the other hand, the body-on-frame chassis is better suited for commercial and heavy-duty vehicles, pickup trucks, SUVs. The BMW i3 and i8 are rare examples of small cars with a separate body and frame.