STATIC AND DYNAMIC ANGLES
What: Alignment angles are measured and adjusted under static conditions—the vehicle is not moving and there are no passengers or load in the vehicle. When the vehicle is moving, the static angles change to dynamic angles; that is, they change as the vehicle moves. Static angles are designed in such a way to produce the ideal dynamic angles when the vehicle is moving.
How: With ideal angles, the front wheels are pointed straight ahead (zero toe) and they are vertical (zero camber). Although you may set the front wheels with toe-in and positive camber during an alignment, ideally, when the vehicle is driven the front wheels are pointed straight ahead and they are vertical.
It does not always happen this way, however. If, for example, the driver of the vehicle weighs 300 pounds, the dynamic angles will be incorrect, even though the static angles were set correctly. The main effect of the heavy weight on the driver's side is to increase camber toward positive on the left front wheel. This would cause wear on the outside tread of the left tire and a slight pull to the left.
In such a case, it would be best to set the static alignment angles with the driver in the vehicle. If this is not possible, add more negative camber to the left front wheel. The point is, often you must adapt your static alignment setting to dynamic driving conditions. You must do this to achieve the basic objective of a wheel alignment—to allow the vehicle to travel straight down the road, with easy steering and minimal tire wear.