Maintain Your New Tires

You've chosen carefully and finally replaced your tires. All done, right? Not so fast. You'll need to maintain your tires properly to ensure that they perform correctly.

Rotating your vehicle's tires is essential to prevent uneven wear. If left unchecked, un-rotated tires will cause increased road noise, lower fuel economy, and decreased wet-weather traction. Badly neglected tires will also have to be replaced sooner.

It is generally accepted that on front-drive vehicles, where all tires are the same size, you rotate the front tires to the rear in a straight line and cross the back tires to the front. In a rear-drive vehicle, you rotate the backs in a straight line to the front and cross the front tires to the back. On all- or four-wheel-drive vehicles, the rotation pattern most often suggested is a simple "X." The left front and right rear swap places, and the right front and left rear swap places.

Many sports cars and some luxury and sport-utility vehicles have unidirectional tires. Unidirectional tires have tread patterns that are designed to perform in the direction denoted on the tire sidewall only. They should always be rotated front to rear (assuming they are the same size). This ensures that the direction of revolution does not change.

If you are rotating a full-size spare into the mix, it is common practice to put that tire in the right rear. Consumers should consult their owner's manual for the correct tire-rotation procedure for their vehicle.

Proper tire inflation is also important for many reasons:

A properly inflated tire will generate less heat or friction with the road, increasing fuel economy and decreasing tire wear.

A tire that's either over- or under-inflated will wear unevenly.

A tire that is low in pressure loses cornering ability because the sidewall isn't as stiff.

Perhaps more important for SUV and light-truck owners, a tire's load capacity decreases as it loses air pressure. So, if you were to pack your SUV to the rafters for a family vacation without adjusting tire pressures to handle the increased load, you may be asking for trouble. Those under-inflated tires would quickly heat up under the extra load and possibly have a failure, leading to travel time lost fixing a flat -- or worse.

Regardless of temperature, tires lose between 1 to 2 pounds per square inch (psi) per month. In addition, for every 10-degree Fahrenheit (12.2-degree Celsius) drop in temperature, a tire will lose another pound of pressure. So a tire left unchecked from the time it was filled to 35 psi on an 80-degree (26.7-degree Celsius) day in May is down by 12 psi on a 30-degree (-1.1-degree Celsius) day in November. That under-inflation will affect fuel economy and wet traction, and also increase tire wear.