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Confused about tire inflation pressure

i have a strange scenario: supposedly my tires should be inflated to 30 psi. they look flat-ish, and when i plug in the air thing at the gas station, it says they’re way above 30. 34, 36 even. what’s wrong? this happens at multiple gas stations. thank you!

Go to an auto parts store, buy a half-way decent pressure gauge (many would say dial gauges are most accurate), and check the tire pressure in the morning before you drive the car. The recommended pressure is “cold” pressure - when you drive the pressure increases as the tires heat up.

With radial tires, you can’t go by what they look like.

But - how old are the tires? If they are very old your sidewalls might be weakened allowing extra stretch and more “flat” look to them. If that is so, I’d replace them.

Gas station gauges, being subjected to wind, water, and numerous people dropping them, are far from accurate

Where are you getting the 30 PSI figure? We need to be sure you’re looking in the right place.

At the gas station, the tires are warm because you’ve driven on them. Also, the gauges on those air pumps are rarely that accurate. You need to use a better gauge when the tires are cold.

You might also consider getting an electric air pump when you buy the tire pressure gauge. That way you can check your tires on your day off before you leave home and fill them while they are cold. If you check them weekly to start, you will see if there are any small leaks. If there are not, you could drop back to every other week or every month. Even monthly checks are far more often than most people check.