How to Understand Why Tire Pressure Readings Vary

There are 4 different reasons, you get different tire pressure readings. So getting a preferred equal amount of air in all 4 tires, can be challenging.

Difficulty: Moderately Easy

Instructions

1. In order to get the proper amount of air pressure in a tire, you need a good air gauge. If all air gauges gave the same accurate reading every time, why would tire stores spend more money for their air gauges? In addition to having a good air gauge, to get an accurate reading, you may need to get a reading 2 or 3 times.

2. Tire pressure readings in the morning will usually be lower than tire pressure readings in the afternoon. If a cold tire reads 32 pounds of air pressure, it may read 35 pounds of air pressure after a 30 minute drive.

3. The outside temperature will have less effect on varying air pressures. However, a 32 pounds of pressure cold tire in July, may have about 30 pounds of pressure in January.

4. 32 pounds of air pressure, when a tire is cold, is a standard for many tires. (Know the maximum tire pressure recommendations for your tires, for safety reasons). Over inflated tires, as well as under inflated tires, are likely to have a shorter life, due to uneven tread wear and other possibilities.

Tips & Warnings

• For consistent tire pressure readings, get them before the first crank of the day, when possible.
• 35 pounds of air, applied to a cold tire, may increase to about 40 pounds of air when the tire is hot. This may cause the tire to be inflated beyond factory maximum recommendations.
• Over inflated tires may yield a very slight increase in fuel economy, but turn your vehicle into a rattle trap. The bumps will be felt more often by you and your vehicle.
• Under inflated tires may decrease your fuel economy.

Resources

• Read Tire Size
• Stop Wheel Wobble & Rocks in a Hubcap Sound
• Change a Flat Tire in Unusual Situations
• Measure Tire Sizes