What is Diagonal Tread Wear / Tread Scuffing?

Diagonal tread wear is intermittent angled wear across the face and all of the way around the circumference of rear tires. It is caused by incorrect rear wheel toe settings that direct the tires to follow a path slightly different than the vehicle.

Uneven and unusual tire wear patterns typically are the result of worn, loose or broken chassis parts, wheel misalignment or extreme service conditions. And while it may seem unlikely, one of the most unusual wear patterns can be found on the rear tires of misaligned front-wheel drive vehicles.

Diagonal tread wear on the rear tires of front-wheel drive vehicles is caused when the direction the alignment points the vehicle's tires is not the same as the vehicle's geometric center line.

If a vehicle's axle toe settings are incorrect, the tires will be pointed further towards (toe-in) or away (toe-out) from each other than intended. Essentially, the tires will be forced to operate as though they are in a gentle, but never-ending curve.

Since the design of pneumatic tires requires them to corner by running at slip angles as they grip the pavement, the severity of the misalignment may cause the pair of rear tires to transition through repeated grip / slip contact while being pulled straight ahead, resulting in a diagonal tread wear pattern.

Minimizing Diagonal Tread Scuffing / Diagonal Tire Wear

Maintaining the vehicle alignment is critical, especially the toe settings.

Periodic tactile tire inspection (running your hand around the circumference of the tire) may reveal developing wear patterns sooner than visual inspections. The tires can be saved if noticed early enough. However if not discovered in time, both rear tires should be replaced.

Periodic tire rotation is also important. The recommended rotation pattern for front wheel drive vehicles allows each tire to serve at all vehicle positions, sharing the work and sharing the wear.

Note: Tire rotation cannot remedy tires that already exhibit significant diagonal tread wear. These tires should be replaced.