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.