The most complex tyre problems are uneven wear patterns. However, reading wear pattern is not an impossible task. We need to understand that uneven wear patterns are symptoms rather than being the problems. More often, it is the result of worn, loose or broken chassis parts, misaligned wheels or extreme service conditions.
One of the unusual wear patterns is the diagonal tread wear on the rear tyres of a front-wheel driven car. It is caused when the wheels of the car do not align correctly and do not follow the vehicle’s geometric center line. Now, you know that if the rear tyres of your front-wheel drive cars are showing signs of diagonal wear, then it is due to misalignment.
To narrow it down further, it is due to your vehicle’s incorrect axle toe settings. Because of this, the tyres will be pointed further towards (toe-in) or apart (toe-out) from each other compared the manufacturer recommended settings. The tyres will be positioned in a way that it simulates the condition of being on a gentle but a never-ending curve.
Generally, while cornering, pneumatic tyres grip the surface running at slip angles. Therefore, the misalignment of the front wheels may cause the rear tyres to grip and slip contact repeatedly while the front wheels are pulling the car in a straight line. This repeated grip and slip is what result in diagonal tread wear pattern.
Getting the alignment checked periodically goes a long way in ensuring better handling, good ride and less tyre wear.
To catch the uneven tyre wear early, it is recommended to run your hands along the tyre tread to feel the uneven pattern. This method helps to detect the problem earlier than it can be noticed visually.