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
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.