Vehicle Suspension and Safety on the Road

Introduction

Driving skills like parking, cornering, and overtaking rely heavily on one’s ability to steer in a fluid but precise manner.

Many fatal rollover crashes and head-on collisions are directly related to our failure to steer our vehicles safely.

We find on the Arrive Alive website a rather comprehensive section on wheel balance and wheel alignment.

Wheel balance and alignment reduce stresses and strains on the vehicle suspension components and improve the handling of the vehicle.

In this section, with assistance from Goldwagen and Febi Bilstein, we would like to focus on the importance of the vehicle suspension on our ability to safely steer a vehicle.

Why is a safe and effective vehicle suspension so important for safe driving?

The suspension of a vehicle not only connects the body of the vehicle to the wheel assembly but also transmits all driving and braking forces generated by the friction between the road and wheels to the vehicle’s body. Even a single worn or damaged suspension part can have an adverse effect on the driving characteristics of a vehicle and jeopardise the safety of the driver, passengers, and other road users.

What are the warning signs that a vehicle owner needs to be concerned about vehicle suspension?

Knocking noises when cornering, going over bumps, braking and driving on uneven road surfaces.
Vehicle pulling to one side when braking.
Vehicle “wandering” on the road and lack of directional stability.
Excessive under or oversteering.
Excessive vehicle leans around corners.
Uneven tyre wear.
Excessive “play” on the steering wheel.

Where do we start with vehicle repair when we spot these warning signs?

We recommend that any diagnosis, maintenance and repairs are carried out by a fully trained and qualified vehicle technician. When the early signs of steering and suspension wear become evident, we recommend taking the vehicle to a reputable workshop for inspection and repair.

What are the components/ auto parts needed for the safe suspension of a vehicle?

Shock absorbers.
Shock top mountings and bearings.
Coil springs.
The stabilizer bar (also known as anti-roll bar), bushes and stabilizer link rod.
Control arms and bushes, some vehicles are fitted with hydraulic control arm bushes, which can start leaking over time.
Ball joints.
Wheels and tyres.
The steering rack and relevant power steering components like pumps, hoses, reservoirs and oil coolers.
Steering rack ends and ties rod ends.

How important is it to understand the concept of "combination parts" when referring to the suspension of a vehicle? Would a damaged part have a negative impact on how well another part is functioning?

The steering & suspension system of a vehicle consists of various precisely manufactured parts that must work together in perfect harmony to improve driving stability, comfort and more important safety. If even one single part is damaged or worn out, it will hurt the performance and durability of the other parts of the system.

How much of vehicle repair and maintenance can be done as a DIY job and when would you recommend professional assistance from a qualified mechanic?

In most cases, we recommend assistance from a qualified technician working for a reputable workshop. There are however parts like stabilizer link rods which can be replaced quite easily and wheel alignment is normally not necessary afterwards. Parts like tie rod ends can also be replaced quite easily but this should be done by a workshop as wheel alignment would be required.

When it comes to more specialised repairs like pressing in of hydraulic control arm bushes, shock absorber replacements, ball joint replacements and repairs to steering racks, there are normally special tools and presses needed to ensure the repair is done according to the OE manufacturing standards, some modern vehicles also require some suspension bolts to be replaced as they are “stretch bolts” and cannot be reused, all bolts and nuts should be torqued according to OE specifications so if you don’t have a torque wrench please visit your workshop.

What are the risks involved in making modifications/ alterations and suspension changes to your vehicle?

Vehicle manufacturers invest millions into the construction of automotive vehicles and their suspension designs, with the aim of safety, comfort, and durability. Did you know that most control arms are designed to rather bend than break when the vehicle experiences a direct impact on the wheel? This will allow the driver to maintain a certain degree of control over the vehicle rather than lose all control, which would be the case if the control arm snapped in two.

As seen in the example above, modification of the steering & suspension set-up can have adverse effects on the safety of the driver and passengers. When done incorrectly, and not considering the direct impact on the rest of the very delicate system, modifications and alterations can negatively influence the vehicle characteristics and compromise the safety of not only the driver of the vehicle but other innocent road users as well.

Suspension modifications or alterations should be performed by a fully trained specialist. In general, the majority of these modifications are found in racing cars and 4 X 4 off-road vehicles.

What would be the most important recommendations to a buyer of auto parts looking to attend to the suspension of his vehicle?

Buy from a reputable spares shop that stocks quality brands as steering & suspension parts are safety-critical parts. Never compromise quality for the price, fitting of inferior quality parts will compromise safety, durability and comfort and cost you more in the long run. “Goedkoop koop, is duur koop!”

Do your homework, try and source a brand that has its name built on quality as your life, and those of your passengers will depend on it.

If you are unsure or unfamiliar with suspension repairs, take it to a reputable workshop. Don’t try and save money by attempting to do it yourself, you might damage other parts and put your safety at risk (if you have seen what damage a compressed coil spring can do, you will know what I am talking about) and end up with additional costs.

A word of appreciation to Goldwagen and Febi Bilstein for the assistance received.