TL;DR
- Use the door-jamb sticker, never the sidewall maximum.
- Set pressure when tires are cold (sat 3+ hours or driven less than 1 mile).
- Air contracts ~1 PSI per 10°F drop, which is why TPMS lights flicker in winter.
- Check monthly and before any long trip. Tires permeate 1-3 PSI per month even sealed.
- Use the load-adjusted PSI when towing or carrying near max payload.
Why pressure matters
The right tire pressure is the single biggest free safety gain you can make. Under-inflated tires flex more, run hotter, and can delaminate at highway speed (the famous Ford Explorer / Firestone recall in the early 2000s was largely under-inflation). Over-inflated tires wear in the center, ride harshly, and lose grip.
Pressure also affects fuel economy. NHTSA estimates each 1 PSI under-inflation across all four tires costs about 0.2 percent in MPG. A typical commuter driving 5 PSI low burns 1 percent more fuel year-round.
Door jamb vs sidewall
Two pressure numbers exist on every car. They mean different things.
Door-jamb sticker (USE THIS)
The vehicle manufacturer’s recommended cold inflation pressure for the original tire size. It balances ride comfort, fuel economy, load capacity, and grip for your specific car. Found inside the driver-side door jamb on every modern vehicle (sometimes inside the fuel filler door).
Sidewall “Max Pressure” (DO NOT USE THIS)
The maximum pressure the tire is rated to hold safely. It is a ceiling, not a target. Inflating to the sidewall max usually over-inflates for your vehicle’s weight, harshens the ride, and accelerates center wear.
Cold vs hot pressure
Tire manufacturers and door-jamb specs always reference coldpressure. “Cold” means the tire has sat at least 3 hours or has been driven less than 1 mile. As you drive, air inside the tire heats up; pressure rises 4 to 6 PSI in normal highway use. Never bleed off hot pressure to match the sticker, you will end up under-inflated when the tire cools.
Temperature and pressure
Air follows the gas laws: pressure drops about 1 PSI for every 10°F drop in ambient temperature. That is why your TPMS warning light comes on the first frosty morning of fall. If your door jamb says 35 PSI and you set them on an 80°F day, by a 20°F morning they read ~29 PSI on a cold-soaked tire, low enough to trigger TPMS even though nothing is leaking.
Top up at the start of each season. In winter, check monthly. See our home FAQ on why tires lose air in cold.
How to check pressure
- Buy a quality digital gauge (~$15). Pencil gauges are unreliable.
- Check when tires are cold.
- Remove the valve cap. Press the gauge firmly onto the valve stem.
- Read PSI. Compare to door-jamb spec.
- Add or release air to match.
- Replace the valve cap (it keeps dirt out of the valve core).
- Reset the TPMS if your vehicle requires it (check owner’s manual).
Load-adjusted pressure
Many trucks, SUVs, and minivans list two PSI values on the door jamb: one for everyday use, one for “loaded” conditions (towing, max passengers, extended highway with cargo). Use the higher value when applicable. Failure to do so on a hot summer highway with a loaded vehicle is the classic recipe for a blowout.
Run-flats
Run-flat tires require the same pressure as standard tires (door jamb spec). The reinforced sidewall lets you drive on at zero PSI for ~50 miles at ~50 mph after a puncture, but only the manufacturer’s exact rating. See our run-flat guide.
Buying tires with TireOrbit
New tires reset the conversation: factory inflation defaults, fresh rubber, no slow leaks. Every TireOrbit price includes a $130 install credit at your selected local installer, covering mount, balance, valves, and pressure-set on delivery. Browse all tires or shop by vehicle.
Sources
- NHTSA tire safety: nhtsa.gov/equipment/tires
- US DOT TPMS regulation FMVSS 138.
- Manufacturer technical data sheets (Michelin, Bridgestone, Continental).