If your vehicle is showing tires wearing out unevenly or cupping on the edges, here are the most likely causes and the parts you'll need to fix each one.
Consistently under-inflated tires will wear heavily on both outer edges. Failing to rotate tires regularly allows normal front-to-rear wear patterns to become severe and uneven.
Incorrect toe or camber angles force the tire to drag or lean as it rolls down the road, rapidly scrubbing off the inner or outer tread edges.
Worn shocks or struts fail to dampen road impacts, causing the tire to bounce rapidly. This creates a scalloped or 'cupped' wear pattern around the circumference of the tread.
Loose tie rods allow the wheels to shift left and right independently while driving, causing erratic toe angles and feathered edge wear on the tires.
Degraded ball joints allow the wheel assembly to tilt outward or inward, leading to severe inner or outer edge wear and potential steering safety hazards.
Torn or collapsed rubber bushings allow the control arms to shift under braking and acceleration, dynamically changing the alignment and scrubbing the tires.
A severely worn wheel bearing allows the entire wheel hub to wobble, causing uneven tire wear that is usually accompanied by a loud humming or roaring noise at speed.