Drivers must understand both the legal requirements and physical principles governing tyre… — UK Driving Theory Test

Drivers must understand both the legal requirements and physical principles governing tyre maintenance and vehicle safety. Match each tyre condition or operational scenario to its corresponding rule, consequence, or required procedure.

Checking tyre pressure immediately following sustained high-speed motorway drivingProduces an artificially elevated pressure reading due to thermal expansion, requiring measurement when cold
Fitting an emergency space-saver spare wheel after experiencing a punctureImposes a strict operational speed limit of $50\text{ mph}$ ( $80\text{ km/h}$ ) strictly for short-term emergency transit
Preparing a passenger car to carry a full load of passengers and heavy luggageRequires increasing inflation pressures to the designated laden specifications detailed in the vehicle handbook
Operating a car tyre with a tread depth of $1.2\text{ mm}$ across the central widthBreaches the statutory UK minimum limit of $1.6\text{ mm}$ across the central three-quarters of the tread breadth

Answer

Checking tyre pressure after sustained high-speed driving matches producing an artificially elevated pressure reading due to thermal expansion; fitting an emergency space-saver matches imposing a strict speed limit of 50 mph (

80\text{ km/h}

); preparing a vehicle to carry a full load matches requiring increased inflation pressures to designated laden specifications; and operating with

1.2\text{ mm}

tread depth matches breaching the statutory UK minimum limit of

1.6\text{ mm}

Each condition matches its foundational legal or physical principle: hot tyres read falsely high due to thermal expansion and must be checked cold; space-saver tyres are restricted to a maximum speed of 50 mph (

80\text{ km/h}

) for temporary use; heavily loaded vehicles require higher inflation pressures to maintain structural integrity; and a 1.2 mm tread depth breaches the mandatory 1.6 mm UK legal minimum across the central three-quarters of the tread.

Step-by-Step Solution

Analyse the thermal effects on tyre pressure checks.

Identified that driving warms the air inside tyres, resulting in higher pressure readings. Correct pressure checks must be performed when tyres are cold.

Prevents accidental under-inflation from bleeding air out of a warm tyre.

Review the operational limitations of a space-saver spare wheel.

Determined that emergency space-saver tyres carry strict mechanical and speed limitations (maximum

50\text{ mph}

80\text{ km/h}

) and must be replaced promptly.

Ensures vehicle stability and safety under reduced contact patch conditions.

Evaluate pressure adjustments needed for heavy vehicle payload.

Matched fully laden conditions with the vehicle handbook instruction to increase cold tyre pressure settings.

Compensates for extra vehicle weight, maintaining optimal tyre footprint, stability, and fuel economy.

Check the statutory UK legal limit for car tyre tread depth.

Recognised that

1.2\text{ mm}

falls below the statutory legal threshold of

1.6\text{ mm}

across the central three-quarters of the tread.

Ensures compliance with road traffic legislation and sufficient water clearance to prevent aquaplaning.

Key Concept

UK statutory tyre regulations, temperature-dependent pressure protocols, load-based pressure adjustments, and emergency spare tyre operational constraints.

Estimated Time:1m 30s

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