How to Check Tyre Pressure Correctly (and Why Monthly Matters)

The rule

The US National Highway Traffic Safety Administration (NHTSA) says proper tyre pressure is the most important part of maintaining your tyres. It affects safety, durability and fuel consumption. Its guidance is to check the pressure of all tyres, including your spare, at least once a month when the tyres are cold, meaning the car has not been driven for at least three hours.

Which number to use

Use the recommended inflation pressure for your vehicle, not the number moulded on the tyre. NHTSA says it is on the Tire and Loading Information Label on the driver's side door edge or in your owner's manual. The US Department of Energy's fueleconomy.gov adds a warning: do not use the maximum pressure printed on the tyre's sidewall.

Why it matters

• Safety: NHTSA says poor tyre maintenance, including not enough air, can lead to a flat tyre, blowout or the tread coming off. In 2024, 511 people died on US roads in tyre-related crashes.
• Fuel: fueleconomy.gov says under-inflated tyres can lower gas mileage by about 0.2% for every 1 psi drop in average pressure of all tyres.

Step by step

• Check in the morning or after the car has been parked for hours.
• Press the gauge firmly on the valve and note the reading.
• Compare it to the door-edge label or manual figure for your vehicle and load.
• Add air or release it to match, then refit the valve cap.
• Do not forget the spare.

Check the tread too

NHTSA says that when the tread is worn down level with the tread indicator, it is time to replace the tyres. Its penny test is US-specific, so in Sri Lanka rely on the indicator bars in the grooves.

Fact-checked on 30 October 2026 against the sources listed below. Tax rules and prices change by gazette, so confirm with Sri Lanka Customs or the Ministry of Finance before you pay.