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  • Writer's pictureTony Begley

Steering and Suspension 101

Updated: Feb 23

Steering Systems

The primary function of your car's steering and suspension systems is to allow the wheels to move independently of the car, while keeping it "suspended" and stable. Any play or uncontrolled motion in these systems results in a deterioration of handling and accelerated tire wear. Vehicle alignment is closely tied to the condition of the steering and suspension systems. Worn or loose components affect the ability to control the toe angle and may result in a loss of directional stability and accelerated tire wear.

The main components of the conventional system are:

  1. Steering Gear Box

  2. Center Link

  3. Pitman Arm

  4. Idler Arm

  5. Tie Rods

diagram of a car steering and suspension system

The main components of the rack and pinion system are:

  1. Rack and Pinion Assembly

  2. Bellow Boots

  3. Tie Rods

Suspension Systems

Worn or loose components affect the suspension system's ability to control motion and alignment angles, resulting in a deterioration of vehicle handling, stability, and accelerated tire wear. The main components of the suspension system are:

  1. Control Arms

  2. Ball Joints

  3. Springs (Coil or Leaf)

  4. Shock Absorbers

  5. Struts

What Are Ball Joints All About?

Ball joints are part of your vehicle's suspension system that connect the steering knuckles to the control arms. A ball joint is essentially a flexible ball and socket that allows the suspension to move and, at the same time, the wheels to steer. Cars and light trucks will have multiple ball joint assemblies depending on their type of suspension system. Like any other suspension component, ball joints will eventually wear out and become loose. Excessive play in the joint can affect wheel alignment and tire wear. Loose joints can also cause suspension noise (typically a "clunking" sound when going over a bump). If a ball joint fails the suspension can collapse causing a loss of control of the vehicle.

What is a Tie Rod End All About?

A car's steering wheel is connected to the steering gear that helps the steering wheel turn the wheels. The steering gear is connected to the wheels via the tie rod ends. The job of the tie rod end is to ensure the wheels are aligned. It provides the adjustment for wheel alignment that keeps the tires from wearing out on the inner and outer edges. If they wear out, the wheels will lose alignment and you may find that the tires and steering wheel are shaking when you drive the car.

Shock Absorbers and Struts - How Do I Know If My Vehicle Really Needs New Shock Absorbers

You need new shocks (and/or struts) if your original shocks (or struts) are worn out, damaged, or leaking. Leaking is easy enough to see - just look for oil or wetness on the outside of the shock or strut - as is damage (broken mount, badly dented housing, etc.). But, wear is often a more subjective thing to judge. There are also instances where the original equipment shocks may not be worn, damaged, or leaking, but may not be adequate for the job they're being asked to do. In such cases, upgrading the suspension with stronger, stiffer, or some special type of shock (or strut) may be recommended to improve handling for trailer towing, hauling overloads, or other special uses.

Shocks and struts do not require replacing at specific mileage intervals like filters or spark plugs, but they do wear out and eventually have to be replaced. How long a set of original equipment shocks will last is anybody's guess. Some original equipment shocks may be getting weak after only 30,000 or 40,000 miles. Struts usually last upwards of 50,000 or 60,000 miles.

But, when exactly a shock or strut needs to be replaced is hard to say. Because the damping characteristics of shocks and struts deteriorate gradually over time, the decline in ride control often passes unnoticed. So, by the time you think you need new shocks or struts it's usually way past the point when they should have been replaced.

Why Replace Them?

Weak shocks and struts won't necessarily create a driving hazard if you continue to drive on them, but there are studies that show worn shocks increase the distance it takes to stop a vehicle on a rough surface. Increased body sway due to weak shocks or struts can also increase the risk of skidding on wet or slick surfaces.

Worn shocks and struts also increase suspension wear - though marginally - but can have an effect on tire wear.

shock absorber wheel steering link and lower control arm of a car

The reason why most people decide to have worn shocks or struts replaced, however, is to improve overall ride quality. If you're sick of bouncing and rocking on rough roads, a new set of shocks or struts will firm up your suspension and restore proper ride control.

If you're interested in performance handling you can upgrade to premium "gas" charged shocks or struts. These are charged with high pressure nitrogen gas to help minimize foaming in the hydraulic fluid inside the shock. This lessens "fade" on rough roads and helps the vehicle maintain better ride control when cornering.

There are also "heavy duty" replacement shocks and struts that have larger diameter pistons than stock. These also provide increased resistance for greater control but may be a little too harsh for everyday driving. Finally, some shocks have special or adjustable valving that allows the amount of resistance to vary.

Another option to consider if you tow a trailer or haul extra cargo are overload or air-assist shocks. Overload shocks have a coil spring around them to increase the load carrying capacity of the suspension (these also tend to ride stiffer than standard replacement shocks). Air-assist shocks have an adjustable air bladder that acts like a spring to carry extra weight. With this type of shock air can be added on an as-needed basis when hauling extra weight.


A strut is basically a shock absorber mounted inside a coil spring. Struts perform two jobs: they provide a dampening function like shock absorbers and they provide structural support for the vehicle suspension. That means struts deliver a bit more than shock absorbers, which don't support vehicle weight - they only control the speed at which weight is transferred in a car, not the weight itself.

Because shocks and struts have so much to do with the handling of a car they can be considered critical safety features. Worn shocks and struts can allow excessive vehicle weight transfer from side to side and front to back. This reduces the ability of the tires to grip the road as well as handling and brake performance.

Begley Auto Repair Steering and Suspension Service and Repair

If your ride quality is suffering, you're experiencing abnormal tire wear, or just want better handling then bring your vehicle to one of our two convenient Bradenton, Florida locations. Have one of our ASE Certified Technicians take a look and provide you with a solution. We have been Bradenton's trusted auto repair shop for over 50 years!


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