Tire wear can be equalized by switching the position of the tires about every 6000 miles (9654 km). Including a conventional spare in the rotation pattern can give up to 20% more tire life.
Follow the recommended tire rotation pattern shown in the illustration or in your owner's manual.
Store the tires at proper inflation pressures if they are mounted on wheels. All tires should be kept in a cool, dry place. If they are stored in the garage or basement, do not let them stand on a concrete floor; set them on strips of wood.
Tire inflation is the most ignored item of auto maintenance. Gasoline mileage can drop as much as 0.8% for every 1 pound per square inch (psi) of under inflation.
Two items should be a permanent fixture in every glove compartment; a tire pressure gauge and a tread depth gauge. Check the tire air pressure (including the spare) regularly with a pocket type gauge. Kicking the tires won't tell you a thing, and the gauge on the service station air hose is notoriously inaccurate.
The tire pressures recommended for your car are usually found on the door post or in the owner's manual. Ideally, inflation pressure should be checked when the tires are cool. When the air becomes heated it expands and the pressure increases. Every 10° rise (or drop) in temperature means a difference of 1 psi, which also explains why the tire appears to lose air on a very cold night. When it is impossible to check the tires ""cold," allow for pressure build-up due to heat. If the ""hot" pressure exceeds the ""cold" pressure by more than 15 psi, reduce your speed, load or both. Otherwise internal heat is created in the tire. When the heat approaches the temperature at which the tire was cured, during manufacture, the tread can separate from the body.
Before starting a long trip with lots of luggage, you can add about 2-4 psi to the tires to make them run cooler, but never exceed the maximum inflation pressure on the side of the tire.
The tires should be checked for damage at every oil change. Any cuts or signs of bulging requires replacement of the tire.
All tires made since 1968, have 8 built-in tread wear indicator bars that show up as 1 / 2 in. (13mm) wide smooth bands across the tire when 1 / 16 in. (2mm) of tread remains. The appearance of tread wear indicators means that the tires should be replaced. In fact, many states have laws prohibiting the use of tires with less than 1 / 16 in. (2mm) tread.
You can check your own tread depth with an inexpensive gauge or by using a Lincoln head penny. Slip the Lincoln penny into several tread grooves. If you can see the top of Lincoln's head in 2 adjacent grooves, the tires have less than 1 / 16 in. (2mm) tread left and should be replaced. You can measure snow tires in the same manner by using the ""tails" side of the Lincoln penny. If you can see the top of the Lincoln memorial, it's time to replace the snow tires.