ASE A4 Suspension and SteeringSuspension System Diagnosis and RepairHard
A customer complains of a recurring vibration that is felt primarily through the steering wheel, particularly at speeds between 45-60 MPH. The vibration lessens after the vehicle has been driven for a while and the tires warm up. The technician has already balanced the wheels and tires, and the problem persists. Which of the following is the MOST likely cause of this vibration?
- AWorn inner tie rod ends
- BOut-of-round tire or wheel assembly
- CWorn steering rack bushings
- DDamaged constant velocity (CV) joint
Show answer & explanationAnswer & explanation
Correct answer: B. Out-of-round tire or wheel assembly
A vibration that is felt through the steering wheel at specific speeds, and lessens as tires warm up, is highly indicative of an out-of-round tire or wheel assembly. As the tire warms, the rubber becomes more pliable, temporarily reducing the effect of the non-uniformity. This is distinct from imbalance, which is typically corrected by balancing.
Why the other options are wrong
- A. Worn inner tie rod ends would cause loose steering, clunking, and alignment issues, but not typically a speed-sensitive vibration that lessens with tire warm-up.
- C. Worn steering rack bushings would cause loose steering, clunking, or play in the steering, but not a speed-sensitive vibration that diminishes with tire warm-up.
- D. A damaged CV joint typically causes clicking or popping noises during turns or acceleration, not a speed-sensitive vibration through the steering wheel that warms out.
Out-of-Round Tire/Wheel
A tire or wheel assembly that is not perfectly circular. This non-uniformity causes a rhythmic vibration, often speed-sensitive, that may temporarily improve as the tire warms and softens.
- Non-circular shape of tire/wheel
- Causes speed-sensitive vibration
- May lessen as tire warms up
Memory trick: Vibration in the wheel, warms up and lessens the feel? Out-of-round, the culprit's revealed!