Tire maintenance - Underinflation It is impossible to determine whether tires are properly inflated by simply looking at them. It is almost impossible to “feel or hear” when a tire is being run underinflated or nearly flat. Tires must be checked monthly with a tire pressure gauge. Pressures should be checked when tires are cold, in other words, before they have been driven on. Driving, even for a short distance, causes tires to heat up and air pressure to increase. We recommend that you manually monitor and check tire pressure inflation with a pressure gauge. Your tires should have the recommended pressure listed by your vehicle's manufacturer. This information can be found in the vehicle owner's manual and often on a placard located in the vehicle's door jamb, inside the fuel hatch, or on the glove compartment door. If you have a plus size fitment that requires a higher inflation pressure, your tire pressure monitoring system will require re-calibration to new inflation pressure. Refer to your tire dealer/installer of plus size tires for proper inflation pressure. We recommend checking air pressure once each month, and before a long trip. Whether you have a full-sized or mini-spare, make sure that it is properly inflated as well. If the TPMS generates improper monitoring or signals, we recommend that you consult your owner’s manual provided with your vehicle and follow-up with your vehicle’s manufacturer.