What is a Car Steering System and How Does it Work?

As important as accelerating and stopping is the ability to change the direction your car is pointing. The steering system takes the driver’s inputs at the steering wheel and changes where your vehicle’s tires are pointed through mechanical means.

And if you haven’t thought much about it before, you may not understand how all of the parts work together.

Learn more about steering systems, the fundamental concepts, various types of systems, and the significance of regular maintenance.

What is a Steering System?

Steering is a system of components, linkages, etc. that allows a vehicle to follow the desired course.

An exception is the case of rail transport, by which rail tracks combined with railroad switches (also known as ‘points’ in British English) provide the steering function. The primary purpose of the steering system is to allow the driver to guide the vehicle.

The steering system converts the rotation of the steering wheel into a swiveling movement of the road wheels in such a way that the steering wheel rim turns a long way to move the road wheels a short way.

The system allows a driver to use only light forces to steer a heavy car.

The rim of a 15 in. (380 mm) diameter steering wheel moving four turns from full left lock to full right lock travels nearly 16 ft (5 m), while the edge of a road wheel moves a distance of only slightly more than 12 in. (300 mm).

If the driver swiveled the road wheel directly, he or she would have to push nearly 16 times as hard.

The steering effort passes to the wheels through a system of pivoted joints. These are designed to allow the wheels to move up and down with the suspension without changing the steering angle.

They also ensure that when cornering, the inner front wheel – which has to travel around a tighter curve than the outer one – becomes more sharply angled.

The joints must be adjusted very precisely, and even a little looseness in them makes the steering dangerously sloppy and inaccurate.

There are two steering systems in common use – the rack and pinion and the steering box.

On large cars, either system may be power-assisted to reduce further the effort needed to move it, especially when the car is moving slowly.

Parts of the Steering system

The components of a steering system are listed below. They are:

• Steering wheel
• Steering column or shaft.
• Steering gear
• Drop arm or pitman arm
• Ball joints
• Drag link
• Steering arm
• Stub axle
• Left spindle and kingpin
• Left tie rod arm

#1. Steering wheel.

The steering wheel is the control wheel to steer a vehicle by the driver. It contains a traffic indicator switch, light switch, wiper switch, etc. It is also called a driving wheel or a hand wheel is a type of steering control in vehicles.

Steering wheels are used in most modern land vehicles, including all mass-production automobiles, as well as buses, light, and heavy trucks, and tractors.

#2. Steering column or shaft.

The Steering column also known as the shaft is fitted inside the hollow steering column. When the steering wheel is turned, the steering shaft will also be rotated. Due to this, the motion is transmitted to the steering box.

The steering column is located at the top of the steering system and attaches directly to the steering wheel. The steering column then attaches to the intermediate shaft and universal joints.

#3. Steering gear.

The pitman’s arm is splined to the steering gearbox rocker arm at one end and the other end is connected to the drag link by a ball joint.

The steering gearbox contains the gears that transmit the driver’s steering inputs to the steering linkage that turns the wheels, and it multiplies the driver’s steering changes so that the front wheels move more than the steering wheel.

#4. Drop arm or pitman arm.

When the steering wheel is turned right or left the pitman transmits the motion it receives from the steering gearbox to the tie rod. A “drop pitman arm” is used to correct the steering when a vehicle has a suspension lift.

#5. Ball Joints.

The ball joints are spherical bearings that connect the control arms to the steering knuckles. The bearing stud is tapered and threaded and fits into a tapered hole in the steering knuckle. A protective encasing prevents dirt from getting into the joint assembly.

#6. Drag link.

The drag link converts the sweeping arc of the steering arm to linear motion in the plane of the other steering links. “The drag link connects the pitman arm to the steering arm, or in some applications, it connects to the tie rod assembly.

#7. Steering arm.

The steering arm is an arm for transmitting the turning force from the steering gear to the drag link, especially of an automotive vehicle.

The basic function of the steering system is to allow the driver to safely and precisely steer the vehicle. Beyond this, the steering system also provides a way to reduce driver effort by making the act of steering the vehicle easier.

#8. Stub axle.

When the steering wheel is rotated, the motion is transmitted to the pitman’s arm through the gearbox. This motion is transmitted to the drag link. Drag link transfers this movement to stub axle which rotates about the kingpin. This turns the right wheel.

#9. Left spindle and king arm.

In automotive suspension, a steering knuckle is that part that contains the wheel hub or spindle and attaches to the suspension and steering components. It is variously called a steering knuckle, spindle, upright, or hub, as well.

The wheel and tire assembly attach to the hub or spindle of the knuckle where the tire/wheel rotates while being held in a stable plane of motion by the knuckle/suspension assembly.

#10. Left tie rod arm.

The right- and left-side tie rods are connected to each other by a center link, which is also mounted to the Pitman’s arm on the steering gear and the idler arm on the passenger side of the vehicle.

Rack and pinion steering are currently the most predominant of the two steering linkage systems.

How Does A Car Steering System Work?

When you rotate the steering wheel, the car responds. But how does this steering system in cars give you a smooth route forward?

A group of parts called the steering system transmits the movement of the steering wheel down the steering shaft to move the wheels left and right – although car wheels don’t turn at the same angle.

In most cars, small trucks and SUVs on the road today, there is a rack and pinion steering system. This converts the rotational motion of the steering wheel into the linear motion that turns the wheels and guides your path.

The system involves a circular gear (the steering pinion) which locks teeth on a bar (the rack). It also transforms big rotations of the steering wheel into small, accurate turns of the wheels, giving a solid and direct feel to the steering.

Types of a Steering System

#1. Rack and Pinion Steering System.

This is the most common type of steering system used in modern vehicles. The system consists of a gear-like mechanism, known as the rack and pinion, that connects the steering wheel to the wheels. The steering wheel rotates, which in turn moves the pinion gear.

The pinion gear then moves the rack, which then turns the wheels. This type of steering system is highly efficient, easy to maintain, and provides precise control over the vehicle’s direction.

Related Post: What Is Rack and Pinion Steering?- A Full Guide

How does a rack and pinion steering system work?

Rack and pinion is the most common steering system, and preferred by car makers and drivers because it’s simple and direct.

The steering wheel turns the steering column which is attached by a coupling (called a universal joint) that transfers the motion to another shaft below it. This arrangement allows some flexibility in where the steering wheel is located.

This second shaft is attached by its other end to a small gear wheel, called a pinion gear, that engages, or meshes, with gear teeth on one side of a bar, called the ‘rack’, that runs at right angles to it across the width of the car. Depending on which way you turn the steering wheel, the gear winds the rack left or right.

#2. Power Steering System.

Many modern vehicles come equipped with power steering systems, which use hydraulic pressure to make steering easier and more convenient. The system consists of a pump, hoses, and a power steering gear.

The pump is driven by a belt connected to the engine and provides the necessary hydraulic pressure to turn the steering wheel with ease. Power steering systems make it easier for drivers to maneuver the vehicle, especially during low-speed driving conditions.

Related Post: What Is Power Steering?- Definition, Types & Working

How does a power steering system work?

Most steering systems in modern cars are power-assisted. The dominant system is hydraulic power assisted steering (HPAS).

A pump powered by the car’s engine forces hydraulic fluid to operate a piston located at the steering gears. Depending on which way you’re turning the steering wheel, this piston pushes the steering gears accordingly.

The system knows which way you’re turning the wheel and with what force because it has a torsion bar that twists as you turn the wheel.

This bar is connected to a steering control valve which opens and closes to let hydraulic fluid into a reservoir, where it acts on the piston.

However, more car makers are now turning to electric power assisted steering (EPAS) systems. These require less power to operate so have a vital role to play in reducing fuel consumption.

A small electric motor located either near the steering wheel or on the steering rack provides steering assistance.

Early versions were criticised for a lack of feel but modern systems use multiple sensors and complex electronics to vary the steering assistance and provide greater feedback to the driver in terms of steering load.

#3. Recirculating Ball Steering System.

This type of steering system was popular in older vehicles and is still used in some trucks and SUVs today. It consists of a gear, ball studs, and worm gear. The steering wheel turns the worm gear, which then moves the ball studs.

The ball studs then rotate the gear, which in turn moves the wheels. While this type of steering system is less precise than rack and pinion or power steering systems, it is durable and can handle heavy loads.

How does a recirculating ball system work?

This system is much less common on cars because it’s less sensitive and more complicated than a rack and pinion system. Instead of a pinion gear and a steering rack, it uses a so-called ‘worm gear’, to which the steering column is connected.

This worm gear has a thread cut into its exterior and passes through a block of metal called the nut that has a corresponding thread on its inside walls.

Where the nut and the worm gear mesh, ball bearings, intended to reduce friction as well as take up any slack as the worm gear turns, pass up and down the channels created by the threads.

As the balls exit, they are channelled back to the top, giving rise to the term, ‘recirculating ball’.

The nut also has teeth cut into the outside of it which engage with teeth on one end of an arm, called the Pitman arm.

This is connected to the steering linkage which has, at either end, track rod ends attached to the wheel hubs. As the steering wheel is turned, so the worm gear turns the nut which turns the Pitman arm, which moves the linkage and turns the wheels.

Common Steering Problems

Steering problems can get worse over time or suddenly appear. Steering problems are dangerous because they make it more difficult for the driver to safely operate the vehicle. Common steering problems can include:

• Difficulty in turning the wheel, especially at rest or lower speeds. This may be caused by a problem with power steering, low power steering fluid, a fluid leak, or worn parts.
• Lack of response from the steering wheel or looseness. This can be caused by worn parts in the steering system.
• Steering wheel vibration or shaking. Vibrations and shaking can get worse over time, when turning, or at high speed. In some vehicles, extreme shaking can be called a speed wobble or “death wobble.” Extreme shaking can make it difficult to control the vehicle and increase the risk of an accident, especially at high speed.
• Drifting or tracking problems. When a vehicle tends to steer to the left or right, does not maintain a straight course, or is stiff in returning to the center, this could make it more difficult for the driver to maintain control, increasing the likelihood of getting into an accident.
• Grinding noises. This can be a steering gear issue or related to worn or damaged parts.

The causes of these steering system safety issues can be related to a variety of defective parts, design defects, manufacturing defects, improper repair, or lack of maintenance. Causes of steering problems can include:

• Defective wheel assembly
• Worn steering or suspension components
• Fluid leaks
• Electrical shorts or malfunctions
• Damages rims
• Damaged tires
• Suspension problems
• Out-of-calibration steering system
• Low-power steering fluid
• Poor alignment
• Broken or defective stabilizers
• Defective suspension bushings
• Defective or damaged control arms
• Tie rod damage

FAQs.