How to Fix Under-Inflated Tires

Use a tire gauge to confirm low pressure, then inflate each tire to the manufacturer-recommended PSI listed on your vehicle’s doorjamb when the tires are cold; re-check with a reliable gauge, inspect for leaks, and seek professional repair if a tire won’t hold air. Under-inflated tires reduce fuel economy, increase stopping distance, and can overheat, so addressing them promptly keeps you safer and saves money.

Know the Right Pressure

Your goal is the vehicle manufacturer’s recommended “cold” tire pressure (PSI), not the maximum PSI printed on the tire sidewall. “Cold” means the car has been parked for at least three hours or driven less than a mile at low speed. Temperature affects pressure: roughly a 10°F drop can reduce pressure by about 1 PSI.

Here are the most reliable places to find the correct PSI for your tires.

• Driver’s doorjamb sticker (primary source; may list different front/rear values).
• Owner’s manual (confirms pressures and special load/towing notes).
• Fuel-filler door or glovebox sticker (on some models).

Confirming the correct target PSI before you inflate prevents over- or under-inflation and ensures optimal handling, tire life, and efficiency.

Step-by-Step: Inflating a Car Tire Safely

Follow these steps to check and inflate a tire accurately, whether you’re at home with a portable compressor or at a service station pump.

1. Park on level ground and let tires cool for at least three hours (cold check). If you must check hot, add about 2–4 PSI to the doorjamb value and re-check when cold later.
2. Find the recommended PSI on the doorjamb. Note if front and rear differ.
3. Use a reliable gauge (digital is best). Unscrew the valve cap and press the gauge squarely onto the valve stem to read PSI.
4. If PSI is below spec, attach the air hose. Add air in short bursts (5–10 seconds), then remove the hose and re-check with your gauge.
5. Repeat until you reach the recommended PSI. Avoid exceeding it; bleed off small amounts by pressing the gauge’s bleed button or the valve core briefly if you overshoot.
6. Reinstall valve caps to keep dirt and moisture out of the valve core.
7. Check all four tires and the spare if your vehicle has one; some SUVs/trucks have a TPMS sensor in the spare.
8. Start the vehicle and drive a few minutes. Most TPMS lights turn off after the system sees pressures back in range; some cars need several miles above 20–30 mph.
9. If the TPMS light remains on or flashes, re-check pressures and consult your manual for reset procedures; a flashing light often indicates a sensor fault.
10. Re-check pressures monthly and before long trips or major temperature swings.

Taking your time with short inflation bursts and frequent gauge checks prevents overinflation and ensures consistent, accurate pressures across all tires.

If the Tire Won’t Hold Pressure

Persistent pressure loss points to a leak or damage. Address the cause before driving at speed.

Common causes and what to do next:

• Puncture in the tread: If smaller than about 1/4 inch (6 mm) and in the repairable tread area, a professional plug-patch from inside is the industry-standard repair.
• Sidewall or shoulder damage: Do not drive or attempt repair—replace the tire. Sidewalls aren’t safely repairable.
• Valve stem or core leak: Replace the valve core or stem; a shop can do this quickly and inexpensively.
• Bead leak (where tire seats on the rim): Often due to corrosion or impact; wheel cleaning or repair and remounting may be required.
• Cracked or bent wheel: Replace or professionally repair the wheel; continuing to inflate is unsafe.
• Sealant use: Emergency sealants can get you moving, but plan a proper repair soon; tell the shop you used sealant to protect TPMS sensors and equipment.

When in doubt, use a spare or call roadside assistance—driving on a leaking or damaged tire risks a blowout and wheel damage.

When It’s Okay to Drive on a Soft Tire—and When It Isn’t

How low is too low? The lower the pressure, the greater the risk of heat buildup, poor handling, and sidewall failure.

• Down a few PSI: Usually safe to drive slowly to a nearby air source within a few miles; avoid high speeds and hard cornering.
• Very low (e.g., under 20 PSI for many passenger cars) or visibly squashed: Do not drive—add air on the spot or install the spare.
• Zero PSI/flat or off the bead: Do not drive—this can destroy the tire and wheel quickly.
• Heavy loads or towing: Treat even moderate under-inflation as serious; load raises heat and stress.

When pressures are significantly below spec, it’s safer to inflate before moving than to limp the vehicle to a pump.

Tools You May Need

A few inexpensive tools make tire maintenance quick and accurate at home or on the road.

• Digital tire pressure gauge (accurate to ±0.5 PSI).
• Portable 12V or battery-powered air compressor with auto shutoff.
• Valve caps and a valve-core tool; spare valve cores.
• Spray bottle with soapy water to spot leaks (look for bubbles).
• Work gloves and a flashlight for low-light checks.

With a good gauge and compact compressor, you can correct pressures anywhere and avoid relying on inaccurate public pumps.

Tips for Bikes and Motorcycles

Bicycles

Bicycle tire pressures vary widely by tire width and rider weight; check the sidewall and your bike manufacturer’s guidance.

• Road bikes: Roughly 70–110 PSI depending on tire width and rider weight; modern wider tires run lower PSI for comfort and grip.
• Gravel/commuter: Often 35–70 PSI, tuned to terrain and load.
• MTB (tubeless): Commonly 18–28 PSI; tubed setups slightly higher to reduce pinch flats.
• Use a bike-specific pump with an accurate gauge; match the valve type (Presta or Schrader).

Start at the recommended range, then fine-tune based on comfort, grip, and pinch-flat resistance.

Motorcycles

Motorcycle pressures are model-specific and sensitive to load and speed; always use the owner’s manual or swingarm/chain-guard sticker values.

• Check pressures cold, before riding.
• Front and rear pressures often differ; obey load/speed-specific recommendations.
• Use a quality gauge and a compact moto pump or station air; avoid overinflation, which can reduce grip.

Correct pressures improve stability, tire wear, and braking—especially critical on two wheels.

TPMS Basics

Most modern cars have a Tire Pressure Monitoring System (TPMS). A steady warning indicates low pressure; a flashing light usually signals a sensor or system fault. After inflating to spec, the light often clears after several minutes of driving; some cars require a manual reset or calibration. Note that some SUVs/trucks monitor the spare tire; a low spare can keep the light on. If you’ve filled with nitrogen before, it’s fine to top up with regular air; nitrogen is optional and mixing is safe.

Preventing Under-Inflation

Simple habits reduce the chances of running on soft tires and extend tire life.

• Check pressures monthly and before long trips or major temperature swings.
• Use the doorjamb PSI, not the tire’s sidewall maximum.
• Re-check a day or two after major weather changes (about 1 PSI per 10°F).
• Inspect tires for nails, cuts, bulges, or uneven wear; address issues early.
• Rotate tires on schedule and maintain proper wheel alignment.
• Replace valve caps and aging valve stems to prevent slow leaks.

Regular checks take minutes and help avoid flats, blowouts, and premature tire replacement.

Summary

Confirm pressures with a reliable gauge when tires are cold, inflate to the doorjamb-recommended PSI, and re-check for accuracy. If a tire won’t hold air, locate the leak and get a proper repair or replacement—never drive on a badly under-inflated or damaged tire. With a good gauge, a small compressor, and a monthly routine, you’ll stay safer, spend less on fuel and tires, and have fewer roadside surprises.

Why is my tire pressure low after filling tires?

Residual Air Loss: Sometimes, air loss occurs after filling tires due to improper sealing or valve issues. Recheck pressure after a few hours to ensure it remains at the recommended level.

How does a tire wear if it’s under inflated?

In contrast to center wear, edge wear may occur when tires are under-inflated. If you’re driving on tires that are under-inflated, the edge of the tires will make the most contact with the road, causing the edges to wear down more quickly.

How to fix low air pressure in tires?

How to Put Air in Your Tires

1. Check your tire pressure. It’s important to complete this step in the morning or when the tires are cold.
2. Park your car in the right place.
3. Remove the tire valve cap.
4. Place the compressor fitting firmly on the tire valve stem.
5. Add air for a few seconds.
6. Replace the valve cap.

What happens if my tires are under inflated?

Underinflated tires can increase rolling resistance, forcing the engine to work harder and consume more fuel, impacting the environment and your wallet. Uneven tire wear is another consequence, reducing tire longevity and requiring premature, costly replacements.