CDL Combination Vehicles TestInspecting Combination VehiclesHard
During an en route inspection, you notice that the trailer's tires on one side are significantly hotter to the touch than the tires on the other side. There are no visible signs of tire damage or low pressure. What is the most likely cause of this discrepancy?
- AA malfunctioning wheel bearing or brake assembly on the hotter side.
- BThe vehicle consistently driving on a banked road surface.
- CImproper alignment of the tractor's steer axle.
- DUneven cargo distribution causing one side to bear more weight.
Show answer & explanationAnswer & explanation
Correct answer: A. A malfunctioning wheel bearing or brake assembly on the hotter side.
Excessive heat in a tire without visible damage or low pressure often indicates internal mechanical issues. A malfunctioning wheel bearing or a dragging brake assembly generates significant friction and heat, which transfers to the wheel and tire.
Why the other options are wrong
- B. Driving on a banked surface would affect both sides similarly or cause very minor, non-significant differences.
- C. Steer axle alignment issues primarily affect the front tires and steering, not typically causing significant, unilateral trailer tire overheating.
- D. Uneven cargo could cause slight temperature differences but usually not 'significantly hotter' without other signs like bulging or sagging.
Tire Overheating Causes (En Route)
Unexpected tire overheating during a trip can point to underlying mechanical issues that require immediate attention to prevent tire failure or further damage.
- Common causes: underinflation, overloading, dragging brakes, bad bearings.
- Can lead to tire blowouts.
- Always check tire pressure and condition.
- Feel for excessive heat during inspections.
Memory trick: Hot tires tell tales of trouble in their bearings or brakes.