What is the reason for still having a slight deviation after performing a four-wheel alignment?

[ParkerFitz]

The reason for still having a slight deviation after performing a four-wheel alignment: The vehicle may have undergone the alignment in a pit-style setup or with the wheels not fully suspended. Due to assembly precision and component wear, there is always a certain amount of free play or slack in the wheels both horizontally and vertically. By lifting the vehicle and suspending the wheels, you can feel this slack by shaking the wheel edges up, down, left, and right with your hands. If, during the alignment, the vehicle's current position happens to be at the extreme of this slack direction, after calibration, the actual position of the wheels changes, resulting in the original issue not being resolved. If a more advanced four-wheel alignment device is used, which includes a rim compensation process, it is specifically designed to overcome this defect. This procedure requires suspending all four wheels before alignment and rotating them forward and backward. During rotation, sensors attached to the vehicle detect the angle changes in the wheels horizontally and vertically. If this value is too large, the system prompts a check for any damaged related components.