I am trying to set up the ride height so I can get ready to go-cart. I have the 3-link. The specs in the manual show 4.5 inches in the front and 5 inches in the rear, measured from the ground to the bottom of the frame. I am trying to set the rear end, but even when I drop it all the way down it is still well above 5 inches. I am measuring from the bottom frame rail beside the passenger seat. Do I need to adjust those numbers based on my tire size? The tank isn't full, would that make a difference?

In general what am I doing wrong?