How to check tire pressure, and how often to do it
Check all four tires, and the spare, once a month and before long trips, on cold tires. Set them to the pressure on the sticker in the driver's door jamb, not the number on the sidewall.
How often should you check it?
Once a month and before long trips, with the tires cold. Check again after a cold spell: pressure drops roughly 1 PSI for every 10 °F, about 5 to 6 °C, that the temperature falls, without any leak.
Why it matters
Tires are the only thing connecting the car to the road. Correct pressure affects handling, fuel efficiency and how long the tires last. Underinflated tires wear unevenly, reduce fuel efficiency and increase the risk of a blowout, especially at higher speeds.
Pressure is also the simplest cause to rule out when a car pulls to one side or vibrates. An electric car is heavier and its torque arrives instantly, which wears tires faster, so checking pressures stays on its list too.
What you need
- A tire pressure gauge
- Cold tires, so measure before you set off rather than after a drive
- The figures on the sticker in the driver's door jamb, including the one for a loaded car
How to check it, step by step
- Measure before you set off. After driving, the gauge reads high.
- Find the pressure on the sticker in the driver's door jamb. The number on the sidewall is the maximum, not the figure for your car.
- If the car will be loaded for a long drive, use the figure for a loaded car on the same sticker. A loaded car needs more.
- Measure all four tires, then the spare, and set each one to the sticker.
- Put the valve caps back on all four. They keep water and road salt out of the valve.
- While you are down there, glance at the tread for uneven wear.
- Write down what you find, so you remember it next time.
What the gauge and the tires are telling you
- The reading is high just after a drive: the tires are warm. The most accurate reading is taken cold.
- All four are lower after a cold night: the temperature, not a leak. Pressure falls when it gets colder.
- Wear down the center of the tread: typical of running overinflated for a long time.
- Wear on the inner or outer edge: usually alignment rather than the tire. Mention it at the next service.
- The car pulls to one side: rule out tire pressure first. Alignment, tire condition and suspension wear can all cause the same.
- A bulge in the sidewall: a break inside the tire. Drive to a tire shop, not onward.
What people get wrong
That the warning light will tell you. By the time a tire pressure light comes on, a tire may already be significantly underinflated, and a manual check once a month catches it sooner.
When to leave it to a workshop
Pressure is yours to check, but uneven wear is worth mentioning at the next service. Wear on one edge usually means the alignment is out, and wheel alignment is a job for a professional. If one tire wears noticeably faster than the others, the cause is usually pressure or the suspension. Cuts, bulges or cracks in the sidewall mean the tire should be replaced, not watched.
Read next
- Tire pressure light: a puncture, or just the cold?
- Car pulls to one side: how to find the cause
- Car shakes while driving: what is causing it
This page is general information and does not replace a professional assessment. Symbols, codes and behaviour vary between makes. Always check the handbook for your own car.
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