Front-end alignment specs are the recommended angles for the front wheels of a vehicle. The vehicle manufacturer sets the specs, which vary by vehicle. Each specification usually includes the preferred angle for the wheel, as well as the acceptable deviation in either direction. Manufacturers provide recommendations for different angles in the wheel and steering system, including the caster, the camber and the toe. The alignment specs may also include the preferred angle for the steering axis.
The caster and camber angles are two of the most important front-end alignment specs. The caster angle refers to the imaginary line that connects the top and bottom pivot points in the steering system. To calculate the angle, a mechanic compares the first line to a second imaginary line that runs straight up from the ground. The caster angle may be negative or positive. The camber angle refers to the way the tire leans left or right as the mechanic views it from the front. A negative camber angle means that the tire leans in; a positive camber angle means that the tire leans out.
Many front-end alignment specs also include the toe angle, which expresses the direction of the tires in comparison to a line that runs down the center of the vehicle from front to back.