ASE A4 Suspension and SteeringWheels and Tires Diagnosis and RepairMedium
A technician is performing a pre-trip inspection on a commercial fleet vehicle. They notice that the tires on the drive axle are worn more heavily on one side of the tread than the other. What is the MOST likely cause?
- AUnderinflation
- BExcessive positive caster
- COverinflation
- DToe misalignment
Show answer & explanationAnswer & explanation
Correct answer: D. Toe misalignment
Toe misalignment causes a scrubbing action across the tire tread as the vehicle moves, leading to feathering or excessive wear on one side of the tread, depending on whether it's toe-in or toe-out.
Why the other options are wrong
- A. Underinflation causes wear on both inner and outer edges, not just one side.
- B. Excessive positive caster primarily affects steering returnability and can cause slight edge wear but is less likely to cause significant one-sided wear compared to toe.
- C. Overinflation causes wear in the center of the tread, not on one side.
Toe Wear Pattern
Improper toe alignment causes a 'scrubbing' wear pattern across the tire tread, often resulting in feathering or accelerated wear on one side of the tire.
- Toe-in causes wear on the outer shoulder.
- Toe-out causes wear on the inner shoulder.
- Can lead to feathering (smooth on one side, sharp on the other).
Memory trick: Toe Scrapes the Tread Sideways.