How to Check Tire Pressure

If you do only one maintenance task on your car, make it this: check your tire pressure every month. It takes 5 minutes, costs nothing, and saves you money on gas AND tires.

Why It Matters

• Fuel economy: 5 PSI low = 3% more gas used
• Tire life: Correct pressure = 20,000+ extra miles
• Safety: Underinflation causes 30%+ of tire-related crashes
• Handling: Correct pressure means better steering and braking

What You Need

• Tire pressure gauge. Digital ($10–$20) or analog stick ($5–$10). Digital is more accurate and easier.
• Air source. Home compressor, gas station air pump, or tire shop.
• Correct PSI for your car. Found on the driver's door jamb sticker.

The Steps

1. Do It When Tires Are Cold

"Cold" means the car has been parked 3+ hours, or you've driven less than a mile. Driving heats tires and raises pressure by 3–5 PSI. If you check when hot, you'll get a falsely high reading.

2. Remove the Valve Cap

Put it somewhere safe — you'll need it back.

3. Press the Gauge Firmly

Press it straight onto the valve stem. You'll hear a quick hiss. The gauge will read. If you don't hear anything, try again with more pressure.

4. Read the Number

Compare to the recommended PSI on the door jamb. Not the max on the tire sidewall.

5. Add or Release Air

• Low? Add air with a compressor, checking every few seconds.
• High? Press the valve core with a small tool to release air.

6. Replace the Cap

Always replace the valve cap. It seals against dirt and moisture. Consider metal caps — they last longer and seal better.

7. Repeat All Four Tires

And the spare! Spares lose air too.

Common Mistakes

• Checking when hot — reads 3–5 PSI too high
• Using the tire sidewall PSI — that's the max, not the recommended
• Forgetting the spare
• Not checking monthly — tires lose about 1 PSI per month naturally
• Ignoring temperature — 1 PSI per 10°F drop
• Over-inflating to avoid future checks — over-inflation is also dangerous

How Often to Check

• At least monthly
• Before long trips
• After temperature changes (cold snaps)
• When the TPMS light comes on
• Before towing or hauling

What About TPMS?

Your TPMS light warns you when pressure drops 25% below recommended — that's already dangerously low. Don't rely on it for regular checks. Use it as a backup.

The Temperature Effect

Rule: 1 PSI per 10°F. So if you set 35 PSI on a 70°F day, and the temp drops to 30°F overnight, you'll wake up to 31 PSI. This is why the TPMS light comes on first cold morning.

In winter, check more often — or add 2–3 PSI to compensate for cold mornings.

If a Tire Keeps Losing Pressure

If one tire loses more than 3 PSI per week with no visible cause:

• Valve stem leak — old rubber valve stem
• Bead leak — tire not sealing to rim
• Small puncture — nail or screw too small to see
• Rim corrosion — especially on alloy wheels
• Rim crack — from a hard hit

Get it checked. Slow leaks turn into fast flats at the worst time.

Free Service

Not sure? We'll check and adjust your tire pressure for free if you're nearby. Call us at 301-556-3973.