Hanger Spacing for Tandem Axle Trailer Using 25-1/4-Inch Leaf Springs

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Question:

I have 25 1/4 inch springs with treq310 equalizer what is my hanger spacing

asked by: Kelley

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Expert Reply:

The distance on center between the spring hanger bolt holes for dual axle setups, with the # APT9 Tandem-Axle Trailer Hanger Kit, should be 29-1/2 inches for double eye springs that measure 25-1/4 inches on center between the spring eyes and for axles that are 3 inches in diameter. This will put your axle spacing somewhere between 33-1/2 and 34 inches.

You will also need to determine the position of the axles 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.

The linked article on trailer suspensions will give you additional information.

expert reply by: Adam R

0

Answer 1

It is likely you can use the Trailer Idler Hub Assembly for 3,500 lb Axles #AKIHUB-5475-35-K as it has the most common bearing and seal for 3,500 lb axles, but you'll need to verify this as we don't have any way of knowing the exact hubs that…

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Answer 2

There is no exact way to determine the leaf spring length. The best way to determine the length for a replacement is by measuring the existing leaf springs. The hanger distance and shackle length can help you get a good idea, but you're looking…

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Answer 3

Thank you for the measurements you provided and for the photo of your trailer suspension mockup showing the spring components' spacing. As long as your shackles do not hit the trailer frame (you mention 1/8-inch clearance) you should be fine, but…

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Answer 4

It depends on the leaf springs you are using. Basically you will need to mock it all up before permanently installing anything on the trailer. Generally speaking the distance between hangers would likely be 24-3/4 inches on center to 29-1/2 inches on…

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Answer 5

I would be happy to help, but the only way to find the exact location for mounting the hangers to your boat trailer is going to be by tacking the hangers in place and moving them around until you get the suspension correct. When done correctly the…

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Answer 6

Your 13-10 equalizers, which should be equivalent to Equalizer #TREQ310 measures 6-1/16 inches from bolt hole to bolt hole (see accompanying photo) and due to that you will need to use the E-Z Flex Heavy Duty Rubber Suspension System #K71-652-00.…

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Answer 7

The center hangers in the Tandem-Axle Trailer Hanger Kit #APT8 that you recently purchased are indeed longer. This is actually pretty common for tandem axle trailers. The reason for the extra length on the middle hanger is related to the shackle…

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Answer 8

The recommended clearance with leaf spring suspension on an unloaded trailer is between 2 - 2-1/2 inches. You should have sufficient clearance with your loaded trailer, as leaf springs only tend to deflect 1-1/2 inch when carrying a load.

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Answer 9

Hey Caleb, so generally what you see is that on lower capacity trailers the wheelbase between the axles is 33 inches and above like 6k or so the wheelbase most commonly seen is 35 inches. This just works out the easiest and corresponds with how most…

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Answer 10

The closest leaf spring set we have available to the 22-1/4 inch length you mentioned is the 3-Leaf Double-Eye Spring #SP-113275. This double-eye leaf spring features a length of 23-1/2 inches from the center of the spring eye to the center of the…

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Answer 11

Front and rear springs hangers should be equally spaced around the center hanger and spring equalizer. It may be that your trailer was modified (if not originally built) with a different height center hanger and that might be how the spacing became…

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Answer 12

Thank you for providing the specs for the suspension components that you already have. Correct hanger spacing really depends on the components being used such as springs, hangers and equalizers. Most of the hanger spacing dimensions that we have are…

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Hanger Spacing for Tandem Axle Trailer Using 25-1/4-Inch Leaf Springs

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