The left front tire has cupping on both the inner and outer treads. What is the most likely cause?

Cupping on both the inner and outer treads of a tire typically indicates that the tire is bouncing or experiencing oscillations as it rotates. This condition can be attributed to various factors, but worn shocks are a principal cause. When shock absorbers are not functioning correctly, they fail to dampen the vibrations effectively, allowing the vehicle's suspension system to react excessively to road imperfections. This results in uneven tire wear, characterized by the periodic high and low spots (cupping) on the tire tread.

In this scenario, the presence of cupping on both sides suggests a consistent issue impacting the suspension's ability to maintain proper contact with the road. If the shocks are worn, they cannot control the movement of the vehicle's body and suspension components properly, contributing to this uneven tire wear. Addressing the shock absorbers can help resolve the cupping and improve overall ride quality and tire longevity.