A customer complains of a vehicle pulling to the right and accelerated wear on the outer edge of the right front tire. The technician inspects the suspension and finds no loose components. Alignment readings show the following: Left Front Camber: +0.5° Right Front Camber: +0.5° Left Front Caster: +3.0° Right Front Caster: +2.0° Left Front Toe: +0.10° Right Front Toe: +0.10° Which of the following alignment angles is MOST likely contributing to the customer's complaint?
- AExcessive positive camber on both front wheels
- BEqual positive camber on both front wheels
- CInsufficient positive caster on the right front wheel
- DIncorrect toe on both front wheels
Show answer & explanationAnswer & explanation
Correct answer: C. Insufficient positive caster on the right front wheel
A vehicle will pull towards the side with less positive caster, or more negative caster. The right front caster of +2.0° is significantly less positive than the left front's +3.0°, causing the vehicle to pull to the right. Accelerated wear on the outer edge of a tire is typically associated with excessive positive camber or excessive toe-in, but the primary complaint of pulling is best explained by the caster difference.
Why the other options are wrong
- A. Excessive positive camber on both wheels would cause wear on the outer edges of both tires, but wouldn't cause a pull to one specific side if equal.
- B. Equal positive camber would cause outer tire wear on both sides, not a pull to one side.
- D. Incorrect toe (toe-in or toe-out) causes tire wear but doesn't typically manifest as a strong pull to one side with equal toe settings.
Caster Angle
The forward or backward tilt of the steering axis when viewed from the side of the vehicle. Positive caster means the top of the steering axis is tilted rearward.
- Influences steering returnability and straight-line stability.
- Unequal caster causes a vehicle pull.
- Too little positive caster can make steering feel light.
Memory trick: When the car pulls, check the 'CAT' (Camber, Caster, Toe) for an uneven stance.