Spring Hanger Spacing Dimensions for a Tandem Axle Slipper Spring Suspension on a 14,0000 lb Trailer

Expert Reply:

The hanger spacing for a tandem axle trailer suspension setup can be determined, but you need to take into account the axle spacing needed for the overall diameter of your wheel and tire combination and the springs you will be using.

Lets say that you plan on using 4 of the 5-Leaf Slipper Springs, # 1203T3, for 7,000-lb Trailer Axles, and that your wheel and tire combinations are the Karrier ST235/85R16 Wheel and Tire, # AM32764.

The AM32764 wheel and tires overall diameter is 31.61 inches, so you will need your axles to be centered at least 33-1/2 inches apart and you might be better off going with 36 inches apart, so there is clearance for the suspension to work and the tires do not contact each other at the center between the axles.

Hanger spacing is also dependent on the center equalizer used in the slipper spring setup. The longer the center equalizer, the wider the axle spacing will be, causing a wider hanger spacing.

To get 33-1/2 inch axle centers, for two 7,000 lb axles using the 5-Leaf Slipper Springs, # 1203T3, and the Tandem Axle Hanger Kit, # AP202-H202, the hanger spacing would be 28-3/4 inches between the front and center spring hangers and 28-3/4 inches between the center and rear spring hangers. This hanger kit uses # 13-4 equalizers.

To get 36 inch axle centers, for two 7,000 lb axles using the 5-Leaf Slipper Springs, # 1203T3, and the Tandem Axle Hanger Kit, # AP216-H202, the hanger spacing would be 30-1/2 inches between the front and center spring hangers and 30-1/2 inches between the center and rear spring hangers. This hanger kit uses # 13-44 equalizers.

The equalizer you referenced, # 13-118-03, is for newer 8,000 and 9,000 lb axles. We carry it as a replacement part and it is not used in any of our hanger kits. If you were to use this equalizer with spring hangers designed for 2 inch slipper springs, you would need to mock up your suspension and determine the hanger spacing you will need. You will also need to make sure there would be clearance between the axle centers for your suspension to move with the wheels and tires you are using.

expert reply by: Bob G