Know Your 4×4: Chassis and Suspension
The chassis is a frame to which the vehicle’s body is mounted, the suspension and axles are fitted to the underside of the chassis, keeping the wheels in contact with the ground.
Consists of two parallel beams running the length of the vehicle, joined by cross members.
Is a unitary construction. The body, chassis, suspension etc. are all integrated. This system gives a 4×4 a comfortable ride. With a monocoque chassis, wheel articulation is reduced and the body is more rigid.
Suspension is the system of tyres, springs, shock absorbers and linkages that connect a vehicle to it’s wheels. They are designed to absorb road shocks while allowing the wheels to maintain contact with the road surface.
This is a suspension system that allows wheels on the front axle to move up and down independently of one another. It is used on most Double and Single Cabs coupled to a live rear axle.
A system allowing all the wheels to move up and down independently. This reduces wheel articulation, while giving a comfortable ride, so it is often fitted to SUVs.
This uses ‘solid’ or ‘beam’ axles which allow opposing wheels on an axle to
operate in tandem Live axles are coupled to either a ‘coil-spring-over-shock-absorber’ combination or leaf springs and shock absorbers. Live axle suspensions are fitted to tough pick-ups and large SUVs as it offers greater wheel travel and load carrying capacity. Some passenger comfort is sacrificed.
This design uses ‘coil-spring-over-shock-absorbers’. The axle is held in place using control arms, or links.
Is a spring that looks like a long metal rod. One end of the rod is attached to the
vehicle’s chassis, the other end is attached to the suspension’s control arm. When the control arm moves, the torsion bar is twisted and then returns to its original form. This is mounted to independent front suspension systems.