Short of getting ackerman angles, center of gravity, roll centers and twenty or so other terms most people don’t want or need to understand. Here is alignment in a nutshell. Simply stated there are really only 3 angles that control an alignment on cars and trucks.
Caster: The least understood angle on the front end. The easiest way to describe caster is this. The right front tire needs to be slightly ahead of the left front tire when looking down from above the car. This helps compensate for the crown in the road. This way the car has directional stability and makes the car go straight down the road. When you turn the steering wheel to go around a corner, castor also raises the car slightly. After the turn is completed, ease your grip on the steering wheel and it will return to straight and level.
Camber: If the top of a tire leans outward, this is positive camber. If the top of the tire leans inward, this is known as negative camber. In most cases the vehicle manufacture wants the tires to stand up almost straight. However, some performance cars require a small amount of negative camber to help the car handle better when cornering.
Toe: The most important tire wear angle. On many cars today toe is the only angle that can be adjusted. Toe-in means the very front of each tire points inward, such as being pigeon toed. This will show as edgewear or feathering on the outside edge of the tire.
Toe-out will mean the very front of the tires point outward. Toe-out will create edge wear on the inside edge of the tires. In most cases you need to be at the same level of your tires… on your hands and knees looking at the front of your tires to see this wear pattern. Misaligned tires will cause excessive tire wear and drastically increase tire expense.
Proper wheel alignment is essential to the safe steering and handling of a vehicle.
Your tires last longer. You get better fuel mileage. Your vehicle behaves properly so as not to dart or wander around on the road. The steering wheel is straight, not crooked to one side or the other, for driving comfort and your turn signals will self cancel properly.
Choose your alignment professional carefully. A good technician with good equipment will keep your tires wearing evenly for a long time.