How to Determine the Correct Tire Pressure for Your Car

What You'll Need
Tire gauge
Air compressor

Determining the correct tire pressure for your car is essential to your vehicle's performance and the life of your tires. Here are some instructions on how to calculate the optimal tire pressure. 

Step 1 - The Car Door

Many cars have the optimal PSI (pounds per square inch) for your tires printed on the inside of the driver's door. There should also be a recommendation in your owner's manual as to the correct tire pressure. Do not go by the number on the tire itself as this is the maximum PSI the tires can hold, which will not be the best amount. 

Step 2 - Conditions

When trying to determine the correct tire pressure, make sure your tires are cold, that the car has not been running for a few hours or has recently only gone a few miles. The heat generated from being on the road increases the PSI and so measuring while the tires are hot is inaccurate. 

Step 3 - Filling the Tires

Use an air compressor to fill the tires. For lots of highway driving, you will want your PSI to be at or close to maximum. For everyday driving, your optimal PSI will usually be 10% below that.