Once the proper tire for the vehicle has been selected the best practice is to replace all four tires at the same time. In fact, on certain all wheel drive & four wheel drive vehicles, the vehicle manufacturers require all four tires to be replaced so the drive trains are not damaged.
Regardless of the type of vehicle, replacing all four tires at the same time, and maintaining the inflation pressure with regular rotation maximizes performance and tread life. However, when the drivers fail to rotate their tires, the tire on one axle may need to be replaced before those on the other axle. If a consumer is relaxing only one tire, they should be advised that the new tire should be mounted on the rear and paired with the tire that has the most remaining tread depth. While the best practice is to replace all four tires, the most important thing to remember is when replacing only two tires, you should be advised that the new tires should be placed on the back of the vehicle.
If the new tires are installed on the front axle with worn tires on the rear, the vehicle is more likely to lose control when turning in wet or sliloerly conditions. While the front tires with the deepest tread depth grip the road, the rear tires won’t grip at the same level. So the possibility of a oversteer condition may increase as the vehicle turns or changes lanes. When the same vehicle approaches the same curve at the same speed with the deeper tread depth tire in the rear and the worn tires in the front, you may feel the loss of control in the steering wheel and make the necessary adjustments to speed and steering. Since the deeper tread depth tires in the rear are gripping better than the worn front tires, the back of the vehicle does not lose control as it turns. The same is true for winter and studded tire installations. When winter or studded tires are applied to the front axle of a vehicle, the chance of Losing control when turning in wet or snowy conditions may significantly increase. Winter tires are best applied to all vehicle positions. If winter tires are applied to the front axle of any vehicle, they must also be installed in the rear.