ASE A4 Suspension and SteeringSuspension System Diagnosis and RepairEasy
A technician is performing a pre-alignment inspection on a vehicle with a MacPherson strut front suspension. The customer reports excessive tire wear on the outer edges of both front tires. During the inspection, the technician notices that the top of both front tires lean outward. Which of the following alignment angles is MOST likely out of specification?
- AExcessive toe-in
- BExcessive positive camber
- CInsufficient caster
- DExcessive negative camber
Show answer & explanationAnswer & explanation
Correct answer: B. Excessive positive camber
Excessive positive camber means the top of the tire leans outward. This causes the tire to ride on its outer edge, leading to excessive wear on the outer shoulder of the tire.
Why the other options are wrong
- A. Excessive toe-in causes feathering wear across the tire tread, not specifically outer edge wear due to the tire leaning.
- C. Insufficient caster primarily affects steering returnability and stability, not direct outer edge tire wear in this manner.
- D. Excessive negative camber causes the top of the tire to tilt inward, leading to wear on the inner edge of the tire.
Positive Camber & Tire Wear
Positive camber is when the top of the wheel tilts outward from the vehicle. Excessive positive camber causes accelerated wear on the outer edge of the tire.
- Top of wheel tilts outward
- Concentrates load on outer tread
- Leads to outer edge tire wear
Memory trick: Positive camber, like a proud chest, pushes the outer edge to the test.