Examkin

Question

Difficulty: HardTires, Wheels, and Rims Inspection

Match each critical tire or wheel defect observed during a pre-trip commercial vehicle inspection with its specific safety hazard or regulatory consequence.

  • Rust streaks or shiny bare metal radiating from lug nut seatsIndicates loose fasteners and ongoing movement that can cause wheel separation
  • Dual tires making contact with each other under loadCauses excessive sidewall friction and heat buildup leading to sudden blowout or fire
  • Welded repairs visible on a wheel rim or discViolates safety regulations due to weakened structural integrity prone to sudden fracture
  • Mixing radial and bias-ply tires on the same axleCreates dangerous vehicle instability due to differing sidewall flex and traction characteristics

Answer

Rust streaks match loose fasteners/wheel separation risk; Dual tire contact matches sidewall friction/fire and blowout risk; Welded rim repairs match prohibited structural alteration/fracture risk; Mixed radial/bias tires match vehicle handling instability risk.
Each defect maps directly to its distinct mechanical hazard: rust streaks or shiny metal at lug nuts signify loose fasteners; touching dual tires cause severe frictional overheating; welded rims represent illegal and structurally compromised components; and mixing tire construction types across an axle degrades steering and braking stability.

Step-by-Step Solution

1
Analyze the mechanical symptom of rust streaks or shiny metal around lug nut seats.
Identified as a primary indicator of loose lug nuts and relative motion between the wheel and studs.
Relative movement rubs away paint and plating, generating fine rust trails on steel wheels or shiny rings on aluminum wheels.
2
Evaluate the thermal and mechanical impact of dual tires touching under load.
Identified as a major fire and blowout hazard from friction between rotating sidewalls.
Adequate spacing is required between dual tires to dissipate heat and prevent abrasive sidewall wear.
3
Examine the regulatory status and metallurgical consequences of welding cracked rims.
Identified as an out-of-service violation due to compromised structural integrity.
Commercial wheels endure severe cyclical loads; field welds introduce heat-affected brittle zones prone to sudden catastrophic failure.
4
Assess the dynamic consequences of mixing radial and bias-ply tires on one axle.
Identified as a serious handling hazard caused by mismatched carcass construction.
Radial tires flex more in the sidewall than bias-ply tires, generating unequal lateral traction and unpredictable vehicle response.

Key Concept

Identifying wheel, rim, and tire inspection defects and understanding their corresponding safety hazards and regulatory prohibitions.
Estimated Time:1m 30s
Rate this question

Topics

Tires, Wheels, and Rims Inspection

More questions from this topic