Correct tyre pressure is one of the simplest and most impactful maintenance checks you can perform. Under-inflated tyres increase fuel consumption, accelerate tyre wear, reduce handling, and increase stopping distances. Over-inflated tyres reduce grip, cause harsh ride quality, and accelerate wear in the centre of the tread. Checking and adjusting your tyre pressure takes five minutes and costs nothing.
Finding the Correct Pressure
The correct tyre pressure for your vehicle is listed on the tyre placard, which is usually found on the driver’s door jamb, inside the fuel filler flap, or in the glovebox. It is also in your workshop manual. The pressure listed on the tyre sidewall is the maximum pressure for that tyre, not the recommended pressure for your vehicle. Different vehicles using the same tyre size may specify different pressures, and some vehicles specify different pressures for front and rear tyres or for different load conditions (e.g., a higher rear pressure when the vehicle is fully loaded).
How to Check
Always check tyre pressure when the tyres are cold (before driving or after the vehicle has been parked for at least three hours). Driving heats the tyres and increases the pressure reading by 4 to 6 psi, which will give you a false reading. Remove the valve cap, press the tyre pressure gauge firmly onto the valve stem, and read the pressure. A digital gauge is more accurate than a pencil-type gauge. Check all four tyres and the spare (if you have a full-size spare, it should be at the same pressure as the road tyres).
Adjusting Pressure
If the pressure is low, add air using a compressor (at a service station or with a portable 12V compressor) and recheck with your gauge. Service station gauges are often inaccurate, so using your own gauge gives more reliable readings. If the pressure is too high, press the small pin in the centre of the valve stem briefly to release air, then recheck. Replace the valve caps when finished, as they keep dirt and moisture out of the valve core.
How Often to Check
Check tyre pressure at least once a month and before any long trip. Tyres naturally lose approximately 1 psi per month through normal permeation. Temperature changes also affect pressure – a 10 degree Celsius drop causes approximately a 1 to 2 psi decrease. This means your tyres may be significantly under-inflated after a few months of winter if not checked regularly.
TPMS Does Not Replace Manual Checks
If your vehicle has a Tyre Pressure Monitoring System, it is set to alert you when pressure drops significantly below the recommended level (typically 25% below). By the time the TPMS light comes on, your tyres have already been under-inflated long enough to cause uneven wear. The TPMS is a safety warning, not a maintenance tool. Regular manual checks keep your pressures optimised.
Recommended tyre pressures for all loading conditions are in your workshop manual. MechanicMate offers PDF workshop manuals for over 960 models at mechanicmate.net/shop.
