For every 10 degrees F change in ambient temperature, tire pressure will change by approximately 1psi.

Inflation Pressure
Proper inflation pressure is essential for achieving maximum performance and mileage. Improper tire inflation pressure can cause severe internal tire damage, which can lead to sudden tire failure and resulting in serious personal injury or death.Improper inflation pressure may result in rapid or irregular wear. Pressures should always be checked when the tires are cold and at least monthly. Under normal tire operation, approximately 1psi of tire pressure will escape every month. Also, for every 10 degrees F change in ambient temperature, tire pressure will change by approximately 1psi.

Vehicle manufacturers list recommended tire pressures for original vehicle tires in the owner's manual or on a placard on the end of the driver's side door or in the glove box.

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When replacing tires on a vehicle, it is recommended and preferred that all four tires be replaced at the same time for continued optimal vehicle performance. However, for those cases where this is not feasible, below are some general guidelines to consider when replacing less than four tires for a light vehicle, whether it is one or two tires. If the vehicle manufacturer has alternate recommendations, always follow their recommendations.

IMPORTANT
In some cases, the vehicle manufacturer may specifically advise against replacing less than all four tires. Always check and follow the recommendations in the vehicle owner’s manual. For 4WD and AWD vehicles, even small differences in outside diameter may cause drive-train damage or mechanical malfunction.

Replacing Two (2) Tires - When a pair of replacement tires is selected in the same size and construction as those on the vehicle, the two newer tires shou ...[more]