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Difficulty: EasyTyre Safety and Requirements

Which tyre condition is most likely to cause heavy steering and increase your vehicle's fuel consumption?

  1. A
    Driving with over-inflated tyres
  2. B
    Driving on tyres with tread depth well above the legal minimum
  3. Driving with significantly under-inflated tyresAnswer
  4. D
    Driving in wet weather with tyres inflated to the recommended pressure

Answer

Driving with significantly under-inflated tyres
Under-inflated tyres create extra rolling resistance because more tyre surface is pressed against the tarmac. This added resistance forces the engine to work harder—increasing fuel consumption—and increases turning friction, causing the steering to feel sluggish and heavy.

Step-by-Step Solution

1
Analyze how tyre pressure affects the contact area and rolling resistance of the tyre
Under-inflated tyres deform and create greater surface contact with the road
When tyre pressure drops below the recommended level, the tyre walls flex excessively and the rolling resistance increases significantly.
2
Connect rolling resistance and surface friction to vehicle symptoms
Increased resistance requires more engine effort and makes turning the wheels harder
Higher rolling resistance forces the engine to burn more fuel to maintain speed, while increased friction against the tarmac makes the steering feel noticeably heavy.

Key Concept

Consequences of incorrect tyre pressures on vehicle handling and running costs
Estimated Time:45s
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Topics

Tyre Safety and Requirements

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