Look at my signature picture below. The third axle is the tag. You can increase/decrease the pressure in the axle which puts more/less weight on the drive axle and corresponding weights on the steering axle. Lifting it raises it off the ground to allow for a shorter turning radius in tight situations without dragging (scuffing) the tires. It provides more stability in windy situations and s smoother ride overall. Weight capacity on my tag is 10,000 lbs......Dennis