Spring Hanger Placement When Using Spring PR6 With Spring Hanger Kit APT9  

Question:

Expert Reply:

If you look at the provided diagram, you can see the recommended spacing of the spring hangers of the # APT9 kit used with the # e64SR springs.

As a first step, you will need to determine the axle placement before welding the spring hangers into place. The general rule of thumb for double axle trailers is that 60 percent of the trailer weight should be forward of the center between the two axles.

There is a formula that can be used to tell you how far to move the spring hangers when mocking up the trailer. Once you have all of the parts you will need to determine the correct position for the two axles. This is done by weighing the trailer weight under the wheels and then weighing the tongue weight. Once these weights are determined, you will need to add the two numbers together to get the total weight.

Once the total weight is determined, you need to measure the distance to the center point between the two axles. Now figure the percentage of tongue weight. If it is more than 10 percent, you will need to subtract 10 percent of the total weight of the trailer from the tongue weight. Then, divide that number by the total weight of the trailer. Next, multiply the answer by the on center distance between axle center and center of the coupler. The result will give you the distance that the center line of the axles should be moved forward.

If you have less than 10 percent tongue weight, you will need to move the axles rearward using the following equation. Take 10 percent of total trailer weight and subtract the tongue weight. Then, divide by the total weight. Multiply that by the center line distance between axle center and center of the coupler. The result will be the distance that the center line of the axles should be moved rearward.

I have provided a copy of the formula used above.

expert reply by: Mike L

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