Why you should always put better tyres on the rear axle
Which axle should have better tyres installed? It may seem complicated, especially since different car models have other types of drive - front, rear, or all-wheel. However, the answer is clear no matter what type of drive we are dealing with. Let us explain.
In an ideal world, we would have the possibility to change the whole set of tyres at the same time. Such an operation would be most beneficial and leave no room for doubt. Unfortunately, it's not always possible. In modern cars, which are usually front-wheel-drive, tyres on the front axle wear out faster.
Why is that? The reason is simple. The front axle is more heavily loaded, both statically and dynamically. This means not only does a larger mass of the vehicle exert pressure on it, but it also has more work to do. The front axle drives the car, steering and braking. Even if we eliminate the drive, two additional functions remain.
In most cars, the front is more heavily loaded with mass, regardless of the road situation. This load only changes slightly, and only during acceleration does it reduce. However, it's rare for the balance to shift to the rear axle. This might only occur in very powerful cars with rear-wheel drive or 4x4.
Additionally, the driver can quickly increase the front axle load by releasing the gas pedal or gently pressing the brake. Therefore, the more significant number of "duties" the front wheels have is partially compensated by their greater grip, resulting from mass distribution.
The situation is different in the case of the rear axle. It is less statically loaded and often does not have the possibility of its additional dynamic loading. In fact, the rear axle leads the vehicle around a curve. The front axle sets the direction, and the rear maintains it. Therefore, car manufacturers usually use more complicated suspension for the rear axle.
Due to the lesser load, the rear axle is more prone to losing grip. For example, during sudden braking on uneven roads, the car can become unstable due to the loss of grip of the rear wheels. In a turn, releasing the gas pedal or even gentle braking can make the rear seem ostensibly lighter, leading to dangerous oversteer skidding.
Which axle should have better tyres in a car?
Therefore, the rear wheels should always have the best possible grip. This can be achieved in two ways - by installing better tyres or loading the rear part of the car. Obviously, the latter option is not always possible or convenient.
Interestingly, in the world of motorsport, and specifically in rally driving, better tyres are usually installed on the front axle. This happens when the driver has to make a decision about fitting specific tyres to a specific axle, for example, when setting out on a loop (several special stages, between which there is no possibility to return to the service area) on slick tyres with two spare rain tyres. If it is wet on a given special stage, the driver may decide to fit the better, i.e., rain tyres to the front wheels. Why?
Because in a rally, safety is not as important as the time to complete the stage. Thanks to such a maneuver, the car brakes much better. In the case of a rear axle skid, the driver can compensate for technical deficiencies with their exceptional skills.
