Wheel alignment is the proper positioning of the wheels in the proper angular relation to the ground, the suspension and is important in the control of the vehicle and reducing tire wear. The major angles that are measured are camber, caster and toe-in. Camber and caster are not always variable, but generally they are examined when there is wear or damage in the suspension elements. Toe-in The inward angle of the wheels is adjustable in front of all the vehicles, and on the back of those with an independent rear suspension, keeping the wheels rolling parallel to each other. A car that is at zero toe-in has the same distance between the rear and front edges of the wheels, and the toe-in actually is a few inches. Misaligned toe-in will result in inappropriate tire wear (because of rubbing against the road surface). Camber is the angularity of the wheels being tilted outwards or inwards respectively, and is positively indicated in positive camber and negatively indicated in negative camber. Camber angle in degrees determines the surface of contact between tires and the road and compensates variation in the geometry of the suspension when turning corners or when on uneven surfaces. Caster is defined as the inclination of the forward steering axis where a positive caster inclination is toward the rear and negative caster inclination is toward the front. Wheel alignment is a meticulous activity that needs specialized equipment, which is why it is recommendable to use the services of a skilled specialist to make the changes.