CDL General Knowledge TestDriving SafelyHard
You are driving a commercial vehicle and your dual tires become hot during operation. What is the most likely cause of this overheating?
- AA faulty wheel bearing.
- BUnder-inflation of one or both dual tires.
- CExcessive braking downhill.
- DOver-inflation of the tires.
Show answer & explanationAnswer & explanation
Correct answer: B. Under-inflation of one or both dual tires.
When one tire in a dual set is under-inflated, it carries less of its share of the load. This forces the properly inflated tire to carry an excessive load, causing it to overheat. This can lead to tire failure and is a common cause of dual tire overheating.
Why the other options are wrong
- A. A faulty wheel bearing can cause heat in the hub assembly, but the question specifically asks about dual tire overheating, which is more directly related to inflation issues.
- C. Excessive braking heats the brakes (drums/rotors, linings), not primarily the tires themselves, unless the brakes lock up and cause a skid.
- D. Over-inflation can lead to uneven wear and a harsher ride, but is less likely to cause significant overheating compared to under-inflation in duals.
Dual Tire Overheating Cause
The most common cause of overheating in dual tires is under-inflation of one or both tires. This leads to uneven load distribution and excessive flexing, generating heat.
- Under-inflated tires flex more, generating heat.
- In duals, one under-inflated tire overloads the other.
- Proper inflation is crucial for tire longevity and safety.
- Check tire pressure regularly, especially before trips.
Memory trick: Duals too hot? Pressure's forgot!