ASE G1 Auto Maintenance and Light RepairSuspension and SteeringEasy
A technician is performing a pre-alignment inspection and notes that the vehicle's left front tire shows excessive wear on both the inner and outer shoulders, while the center tread is significantly less worn. Which of the following alignment conditions is the most likely cause of this wear pattern?
- AExcessive toe-in
- BExcessive positive camber
- CInsufficient tire inflation pressure
- DExcessive negative camber
Show answer & explanationAnswer & explanation
Correct answer: C. Insufficient tire inflation pressure
Excessive wear on both the inner and outer shoulders of a tire, with less wear in the center, is a classic indication of insufficient tire inflation pressure. When a tire is underinflated, its sidewalls bulge, causing the shoulders to bear most of the load and leading to accelerated wear in those areas.
Why the other options are wrong
- A. Excessive toe-in would cause a feathering wear pattern across the tread, not distinct shoulder wear.
- B. Excessive positive camber would cause wear primarily on the outer shoulder.
- D. Excessive negative camber would cause wear primarily on the inner shoulder.
Tire Underinflation Wear
Insufficient tire inflation pressure leads to excessive wear on both the inner and outer shoulders of the tire, with the center tread remaining relatively unworn.
- Shoulders bear most of the load.
- Center tread sags and makes less contact.
- Reduces fuel economy and tire lifespan.
Memory trick: Shoulders Suffer when Pressure's Low, like a Heavy Load on a Slumped Row.