Wheel alignment refers to the adjustment of the angles of the wheels relative to each other and to the car's chassis. This adjustment is necessary to ensure that the wheels are perpendicular to the ground and parallel to each other, as specified by the vehicle manufacturer.

Several key angles are adjusted during a wheel alignment:

1. Toe: This refers to the angle at which the tires point inward or outward when viewed from above. Proper toe alignment ensures that the tires are pointing straight ahead and are parallel to each other.

2. Camber: Camber is the angle at which the tires tilt inward or outward when viewed from the front or rear of the vehicle. Proper camber alignment ensures that the tire's contact patch with the road is optimized for even wear and handling stability.

3. Caster: Caster is the angle of the steering axis when viewed from the side of the vehicle. Proper caster alignment affects steering stability, steering effort, and return ability to the center position after making a turn.

Wheel balancing is the process of balancing the weight of a tire and wheel assembly so that it travels evenly at high speeds. Balancing requires putting a mounted wheel and tire on a balancer, which centers the wheel and spins it to determine where the weights should go. Every time a wheel is first mounted onto a vehicle with a new tire, it has to be balanced. The goal is to make sure the weight is evenly distributed throughout each of the wheels and tires on a vehicle. This process evens out heavy and light spots in a wheel, so that it rotates smoothly.