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Difficulty: MediumHydroplaning and Wet Road Traction Loss

When driving in heavy rain, wider tires installed on a light passenger vehicle will hydroplane at lower speeds than narrower tires installed on a heavier vehicle with equal tread depth.

Answer: Answer

Answer

The statement is true because wider tires on a lighter vehicle spread weight over a larger area, reducing contact pressure and allowing standing water to lift the tires at lower speeds.
Hydroplaning occurs when the hydrodynamic pressure of water under the tire equals or exceeds the downward contact pressure exerted by the vehicle. Wider tires spread vehicle weight over a larger area, and lower overall vehicle weight reduces the downward force. Together, these factors lower the ground pressure, enabling standing water to penetrate beneath the tread and lift the vehicle at lower speeds.

Step-by-Step Solution

1
Analyze how vehicle mass affects downward contact pressure on wet roads.
Higher vehicle mass creates greater downward force per contact area, helping tires push standing water out of the way.
Adequate contact force is required to prevent standing water from forming a liquid wedge under the tire.
2
Evaluate how tire tread width influences ground pressure distribution.
Wider tires distribute downward weight across a broader surface, decreasing the pressure exerted per square inch of contact patch.
Lower unit pressure reduces the tire's physical ability to displace water through its tread channels effectively.
3
Synthesize the combined effect of tire width and vehicle weight on the hydroplaning threshold.
The lower ground pressure of wider tires on a light vehicle enables water to separate the tire from the pavement at lower vehicle speeds.
Hydroplaning occurs when water pressure exceeds the vehicle's downward contact pressure against the road surface.

Key Concept

Tire Width and Vehicle Mass Effects on Hydroplaning Thresholds
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Topics

Hydroplaning and Wet Road Traction Loss

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