During traffic operations, what is the recommended action if you suspect your dual tires have a diameter difference greater than the allowed limit?

• A. Continue driving slowly
• B. Stop and service to restore tolerance
• C. Remove one tire permanently
• D. Replace with a spare

Answer: (B)

Matched dual tires on an axle must stay within a small diameter difference. If you suspect the difference is greater than the allowed limit, stop at a safe location and service to restore tolerance. That imbalance means the tires don’t rotate in sync, which can cause steering pull, increased sway, vibration, and excessive heat, raising the risk of tire failure or loss of control.

To fix, inspect both tires for wear or damage, measure the diameter, and replace the tire(s) so the pair matches within spec. Ensure proper inflation and load rating, and recheck the difference before resuming travel. Continuing to drive with a mismatch is risky, and using a spare isn’t appropriate unless it matches the diameter.