The steering system is a mechanism that enables the driver to guide and direct the vehicle in a chosen direction.
Suspension is the term given to the system of components, springs, shock absorbers and linkages that connects a vehicle to the road surface via the wheels and tyres.
Suspension systems serve a dual purpose — contributing to the car’s road holding/handling and braking for good active safety and driving pleasure, and keeping vehicle occupants comfortable and reasonably well isolated from road noise, bumps, and vibrations.
These goals are generally at odds, so the tuning of suspensions involves finding the right compromise. It is important for the suspension to keep the wheels in contact with the road surface as much as possible, because all the forces acting on the vehicle do so through the contact patches of the tyres. The suspension also protects the vehicle itself and any cargo or luggage from damage and wear. The design of front and rear suspension of a car may be different but the following diagrams show a common type of system.
The steering wheel is connected to the rack and pinion system, which moves the wheels right and left via the inner and outer tie rods. These are connected using a track rod end.
The track rod ends are adjusted to ensure the wheels are perfectly aligned (“Tracking”) and that tyre wear is minimised. The track rod end is a common wear item and simple to replace.
A CV joint (constant velocity joint) is part of a drive shaft (the shaft that attaches to a car’s transmission at one end and the wheel at the other). CV joints are designed to be able to bend in any direction while continuing to turn the drive wheels at a constant velocity. CV joints are mainly used in the drive shafts of front wheel drive cars.
Due to bumps and uneven surfaces in the road, a car’s wheels tend to move up and down continuously while driving down the road; as a result, drive shafts cannot be made up of a solid shaft.
The CV joint is used in front wheel drive cars because of its ability to maintain a constant drive force to the wheels despite the many different kinds of movements in the front end of the car. The CV joint is often used in rear wheel drive and four-wheel drive cars too. CV joints should be checked regularly and may need replacing as a car ages.