The geometric and physical forces behind a front-wheel turning system are complex, but they help your front-wheel vehicle stay centred on the road. How specifically, though, do these forces go to bat for you? And what do you need to know about them to preserve – or, at least, monitor – the condition of your car tyres?

An introduction to steering systems

Most vehicles on the road today benefit from front-wheel turning systems. This system places the bulk of the responsibility for your roadway safety on your front-wheels. What does it look like, though, when your car controls work to help your tyres generate the camber and torque you need to move forward?

Front-wheel turning systems can’t generate the necessary force to move your car without a balanced steering axis. The steering axis is also known as the King Pin Inclination (KPI). This access isn’t a physical part of your car. Instead, it’s a mathematical idea. Car manufacturers find your car’s steering axis by drawing two intersecting lines between your upper and lower ball joint pivots.

mechanical trails and steering system

Your car’s steering axis helps your front tyres generate positive camber. When your tyres shift away from your car’s centre axis, your tyres create a new angle with the road. This angle, known as your camber, will let your car self-right and avoid drift more effectively.

Your steering axis creates other imaginary points around your car that automotive manufacturers need to consider if you’re going to stay safe on the road. One such point is your mechanical trail. Your mechanical trail is a line between your steering axis and the part of your tyre that comes into contact with the road.

When a manufacturer can readily identify your mechanical trail and steering axis, they’ll be able to ensure that your ride is smooth and centred. Without a steering axis, mechanical trail, or affiliated pneumatic trail – which describes the path of your tyres on the road – your car wouldn’t be able to generate the torque or camber it needs to turn.

Front-wheel versus rear-wheel steering systems

Silver car on a white background

Both front-wheel and rear-wheel vehicles have steering axis and the aforementioned trails. How, though, do these elements vary from steering system to steering system?

Front-wheel vehicles benefit, as mentioned, from the self-righting measures that their steering axis and aforementioned trails allow. It’s the torque, after all, generated by the mechanical trail that helps keep your car on the road. More so than that, though, the steering axis and trails allow your car to readily adjust to new inclines, turning on a dime without causing you any distress.

Comparatively, vehicles with rear-wheel steering systems are a little less balanced than their front-wheel peers. This imbalance can be blamed on a reverse axis torque. Think of it this way: when you go to turn left on the road, a rear-wheel steering system will rotate your car tyres to the right, and vice-versa.

While you’ll still readily make your turn, the mechanical and pneumatic trails won’t be as stable as they are in front-wheel vehicles. As such, you’re at more risk for an accident if you head off-road or onto an uneven highway.

How your steering systems affect your tyres

Tyres and steering system

It doesn’t matter whether you’re off-roading or driving to and from work every day. Both front-wheel and rear-wheel steering systems are going to impact the health of your tyres. Because both systems will demand significant force from your tyres, your tyre tread will wear relatively quickly on the tyres that turn most often. 

Think of it this way: the front set of tyres on a front-wheel vehicle will wear faster than the rear tyres, and vice-versa for rear-wheel vehicles. Comparatively, 4x4 tyres and off-roading tyres tend to wear evenly.

This is why it’s especially important to keep an eye on your tyres. While your wear will vary based on the distance you drive and the environments you drive through, you never want to find yourself driving on bald tyres. When you know which tyres your steering system relies on most often, you can better determine which tyres may need to be replaced when. 

When in doubt, make sure that your tread is deep enough to meet the Queen’s head on a pound coin. If it’s any shallower than that, you’ll need to make your way to a garage to have your tyres replaced.

Your steering system may influence the balance and flow of your car, but you don’t have to let it work faster than you do. Take the time to learn about your specific vehicle’s steering system, and you’ll be better able to equip it with the high quality tyres it deserves.