The # APT4 Tandem-Axle Hanger Kit will provide about 4 inches of clearance from the center of the trailer axle to the bottom of the trailer frame, with no load on the axle. This is assuming that your axle tube is 3 inches diameter. If your axle tube is smaller the height will be sightly less. The curve of the springs you select will have some affect also.
I would recommend that you go with the APT5 hanger kit because all of the hangers are the same height and it will make it easier to... view full answer...