Spring Hanger Position for Tandem Axle Trailer with 6000 lb Axles

Question:

I have an 18 ft long tandem axle utility trailer that doesnt have axles on it at the moment. The ones that were on it previously didnt have sufficient weight rating for my needs, and had to be cut off because the bolts were seized and couldnt be removed. Everything was removed including the hangers. I have two 6000 lb axles that I will be putting on, but Im uncertain how to determine the correct placement based on the weight of my trailer, as I am going to turn it into an enclosed trailer. The framing will be made of wood and I dont know how to estimate how much it will weigh once installed. Also, I will have some permanently-installed equipment inside which I havent yet purchased and dont know the weight of. Can you offer any guidelines as to how to calculate the correct placement since I dont know total weight or tongue weight?

asked by: Jalina

Helpful Expert Reply:

To determine the location for the axles on your tandem axle trailer you will first need to make sure that you have the correct center point for your equalizer hanger.

The center point of your equalizer hanger needs to be located where you will have 60 percent of the frame of the trailer in front of the center of the equalizer hanger and 40 percent behind the center of the equalizer hanger. For example, if the trailers frames length is 18 feet, then the center-line location for the equalizer hanger will be 10.8 feet from the front of the trailer and 7.2 feet from the back.

I am including a good picture of the measurements that are required on a tandem axle and a chart that will list the hanger distances on a 2,000-lb axle and a 3,500-lb axle. The picture is from the product page of the Tandem-Axle Trailer Hanger Kit for Double-Eye Springs, part # APT1. This kit uses an 8 inch long equalizer and the leaf springs listed for a 3,500-lb axle have a length of 25-1/4 inches. If your leaf springs have a length of 25-1/2 inches you will need to add a 1/4 inch to the front hanger distance and the rear hanger distance.

I am including links to some FAQ pages on trailer suspensions and leaf springs.

expert reply by: Jameson C