Uneven wear happens because tires aren’t all exposed to the same stress level. For instance, the tires that take the brunt of the braking and those connected to the drivetrain have different loads. The NHTSA recommends that you rotate your tires every 5,000 to 8,000 miles. While that’s a safe bet, reading your vehicle’s manual is better to know how often you should rotate them and what rotation pattern is best.
Most people own a front-wheel drive (FWD) vehicle because they’re cheaper to make and supply better traction. However, with FWD, the front tires are responsible for turning, braking, and propelling the car forward — that’s a lot of stress. A diagram on the NHTSA’s website suggests front-wheel drive cars should advance their two front tires to the back, the left back tire to the front right, and the right back tire to the left front.
Unsurprisingly, rear-wheel and all-wheel drives have a different pattern for rotating tires. The diagram suggests an inverse for these drivetrains where you advance your back tires to the front, then advance your left front tire to the right back and the right front to the left back.
Nonetheless, if you notice your tires have worn out unevenly, you may have to exchange all your tires. Be more careful in the future to avoid uneven wear because it can provoke bad traction, leading to accidents.