....Weight-jacking refers to adjusting the lower spring perches up or down to alter how much weight is on that particular diagonal of the car. Weight-jacking can only be done diagonally, to change the cross weights. Weight-jacking does not shift weight from one side of the car to the other, or from the front end to the back end. The front-and-rear weights will always remain the same, and the left side and right side weights will always remain the same. The only way to change the front-to-rear, or side-to-side weight percentages is to move something around in the car.