What PSI Should My Tires Be? How to Find and Check It
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The right tire pressure is not the number molded into the tire sidewall. That number is the maximum the tire can safely hold. The pressure your car needs is set by the car maker, and it is usually lower.
Where to find your car's correct PSI
Open the driver's door and look at the door jamb. Most cars sold in the US have a tire placard there listing the recommended cold pressure for the front and rear tires, and sometimes for the spare. If it is not on the door jamb, check the owner's manual, the inside of the fuel door or the glovebox lid.
Most passenger cars land somewhere in the low to mid 30s PSI, but trucks, SUVs and some performance cars are different, and front and rear can differ on the same car. Go by your placard, not by a general rule.
Check it cold
The placard number is a cold pressure. Driving warms the tires and the air inside them, which raises the reading. For an accurate check, measure before you drive, or after the car has been parked for a few hours.
Temperature matters across the seasons too. When the weather turns cold, tire pressure drops, which is why the low-pressure warning light often comes on the first chilly morning of the year. It is worth checking once a month and whenever the temperature swings.
How to check and fill your tires at home
- Find your target. Read the cold PSI for the front and rear tires on the door placard.
- Remove the valve cap and keep it somewhere you will not lose it.
- Attach the gauge or inflator hose firmly to the valve so it does not leak.
- Read the pressure. If it is below the target, add air. If it is above, press the small pin in the center of the valve briefly to let some out, then check again.
- Repeat for all four tires, and the spare if it has one, then put the caps back on.
A cordless inflator makes this a two-minute job in your driveway. With the Dashnox ePump, you set the target pressure on the display, press start, and it stops on its own when it gets there, so you do not have to stand over it watching a gauge. It charges over USB-C, has a built-in LED light for roadside use at night, and comes with adapters for bike tires (including Presta valves), sports balls and inflatables.
What happens if your tires are under or over inflated
- Under-inflated tires flex more, run hotter, wear faster on the outer edges and can hurt fuel economy and handling.
- Over-inflated tires have a smaller contact patch, so grip and braking can suffer, the ride gets harsher and the center of the tread wears faster.
When the tire pressure light comes on
Most newer cars have a tire pressure monitoring system that lights up when one or more tires is well below the recommended level. Check all four tires with a gauge, fill them to the placard number and drive a short distance. If the light stays on, or one tire keeps losing air, have it checked for a puncture or a leaking valve.
Quick answers
Should I fill to the number on the tire? No. Use the number on the door placard. The sidewall number is the maximum, not the target.
How often should I check? About once a month, before long trips and when the weather changes.
Can I use the same pump for my bike? Yes, if it has the right adapter. Road bikes often use Presta valves, which need a Presta adapter.
Keep a small inflator in the glovebox and a low tire becomes a two-minute fix instead of a trip to the gas station. See the Dashnox ePump.