There are telltale signs of a vehicle in need of wheel alignment. The tire that is pointing off-center will pull the vehicle in the direction it is oriented. For example, if the right front tire is nudged slightly inward (left), the steering wheel will pull left while driving on a flat, even surface. The driver will have to maintain a right-pull on the steering wheel to keep the vehicle headed straight —- even when driving on a flat, straight road. This is not only annoying, but the tire that is out of alignment will also wear prematurely and unevenly because of the constant drag placed on its tread. The drag can also impact gasoline mileage.
Uneven tread wear is a sign that the car was driven quite a while with improper wheel alignment. Often, the inner tire tread will wear down smooth while there is still plenty of outer tread left, or visa-versa. The result is that tires have to be replaced sooner rather than later. If tread wear is "cupped," the vehicle was driven with the tires out of balance as well.
Wheel alignment normally takes less than one hour. The vehicle is placed on a platform, which allows the wheels to spin while a computer calculates orientation. The computer compares this to a database of manufacturer specifications for the year, make and model of the car. If wheel alignment is off, an adjustment is made and the vehicle is tested again. Balancing can be done at the same time, if required.