If the tires are worn unevenly, the vehicle is unstable on the highway or the handling is uneven during spirited driving, it is essential that you check the wheel alignment. Begin by checking for the wrong tire pressure and other causes, such as worn parts of the suspension or steering, accident damage, or unmatched tires. Any kind of worn or damaged components must be replaced before proper wheel alignment can happen. This process requires expensive equipment and precise adjustments so it should only be done by a trained technician at a properly equipped shop. The angles that are adjustable on most vehicles are caster, camber and toe, angles whose predominant effect is on vehicle handling. Caster angle, viewed from the side, describes the steering axis and positive caster improves directional stability but too much positive caster will make steering difficult. Camber, when viewed from the front, is the tilting of the wheels, negative camber can lead to better contact of the tires on turns but too much can lead to a lack of straight line stability. Toe angle - seen from above, this is a measure of how far apart the front and back of the wheels are; a little negative toe can increase stability as well as give a smoother ride on the highway.