If your tires are not wearing down uniformly, then there may be a problem with the car that may not even be related to the tires. Different forms of wear point to different problems. Here are three examples of car wear, and what they may mean:
Camber is the angle a car's wheels make with the vertical axis of the vehicle. Camber wear, therefore, occurs unevenly on one side of a tire tread. It occurs when the tire is leaning to one side, with one side pressing on the road more than the other side. The side of the tire pressing on the road too much experiences high friction that leads to increased wear.
Camber misalignment may occur due to maladjustment in the wheel assembly system (such as loose ball joints) that allows the wheel to lean in or out. It may also occur when you lower your car's suspension, but doesn't do a good job of it and even a collision may cause physical damage to the when assembly and cause camber misalignment.
Just like the name suggests, diagonal wear occurs across the face of the tire from one side to another. This type of wear occurs if the tires are misaligned and do not face direction as the car's centerline when you are driving in a straight line. In essence, your tires will be rotating as if they are in a never-ending curve, even if you are driving straight forward.
Apart from misalignment, other possible causes of diagonal wear include carrying (especially if you do it frequently) heavy loads whose weights aren't properly distributed in the car. Such weights may change the geometry of the suspension system. Even an incorrect toe setting may result in a diagonal wear.
This is what you are dealing with if the center of the tire is more worn than other parts. It occurs if only the center of the tire is in contact with the ground, or it presses too much and the other parts only brush the ground.
The most common cause of center wear is over-inflation, which bulges out the center ring and increases its friction with the ground. Check the door placard or your owner's manual for guidance on the correct tire pressure for your car. The problem may also occur due to a mismatch between the wheels and tires.
Therefore, don't just replace your tires whenever you see them wearing unevenly. If you can't diagnose the issue, take your car to a mechanic (such as Felix Auto Repair & Towing) so that your new tires do not go the same route.