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Difficulty: EasyTires, Wheels, and Rims Inspection

During a commercial motor vehicle pre-trip inspection, a driver identifies several physical conditions across the tires, wheels, and rims. Match each inspection observation with its corresponding regulatory violation or primary safety hazard.

  • Rust trails spreading outward from around wheel lug nutsIndicates loose wheel fasteners that may lead to wheel separation if not retorqued
  • Dual tires mounted with sidewalls making direct physical contactGenerates severe friction and dangerous heat buildup between tires, risking a blowout or fire
  • Missing valve stem dust caps on tire inflation valvesAllows dirt and road debris to enter the valve core, leading to slow air leaks and underinflation
  • Front steering axle tire measured at 332 inch\frac{3}{32}\text{ inch} of remaining tread depth in major groovesViolates the mandatory minimum tread depth requirement of 432 inch\frac{4}{32}\text{ inch} for front steer tires

Answer

Rust trails correspond to loose wheel fasteners; dual tires touching correspond to dangerous friction and heat buildup; missing valve stem caps correspond to dirt entering the valve core causing air leaks; and a steer tire with 332 inch\frac{3}{32}\text{ inch} tread depth corresponds to a violation of the 432 inch\frac{4}{32}\text{ inch} minimum steer axle tread requirement.
Each observation maps directly to its established safety and regulatory hazard: rust streaks signify loose lug nuts; dual tires in contact cause destructive friction and tire fire risk; missing valve stem caps allow particulate contamination of the valve core resulting in air loss; and a steer tire measuring 332 inch\frac{3}{32}\text{ inch} fails the mandatory 432 inch\frac{4}{32}\text{ inch} front axle tread depth regulation.

Step-by-Step Solution

1
Evaluate the wheel fastener condition.
Rust streaks around lug nuts indicate loose or unseated nuts.
Relative motion between the nut and rim surface grinds metal and produces rust tracks.
2
Analyze dual tire spacing.
Direct sidewall contact generates severe friction and heat.
Dual assemblies require clear air spacing to dissipate heat and prevent sidewall abrasion.
3
Determine the role of valve caps.
Missing caps permit road debris into the core, causing gradual leakage.
Valve caps provide a secondary seal against contamination.
4
Apply statutory tread depth thresholds.
A steer tire with 332 inch\frac{3}{32}\text{ inch} is below the legal 432 inch\frac{4}{32}\text{ inch} minimum.
Steer tires require greater minimum tread depth (432 inch\frac{4}{32}\text{ inch}) than non-steer tires (232 inch\frac{2}{32}\text{ inch}) to maintain steering traction.

Key Concept

Commercial Motor Vehicle Tire and Wheel Defect Identification and Safety Thresholds
Estimated Time:1m 0s
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Topics

Tires, Wheels, and Rims Inspection

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