How to Determine Spring-Center and Hub-Face Measurements when Building a Trailer

Question:

Hello I am attempting to build an off road trailer for camping and such. The trailer will be 4x8 and Id like to use hubs to fit my 6x5.5. Im pretty sure this means i will buy 48 inch spring center but im not sure which overall length axle to get.

asked by: Jim

Expert Reply:

It sounds like you are heading in the right direction. To decide where your springs seat will be you will need to mock up your trailer as if you were installing all of the equipment on it.

Once you have the suspension part mocked up you will want to measure the distance between the middle of your hangers since that is where the middle of your spring seats will be. If that measures 48 inches, like you believe it will, then you will just need to find what the hub-face dimensions are needed.

To find your hub-face-to-hub-face measurement you will need to mock up your trailer and measure from where the base of one wheel stud will be to where the base of the other wheel stud will be (see attached photo). We recommend having at least 2 inches of space between the tire and the frame of your trailer. You can then look at axles with the same spring-center and hub-face measurements that you took.

Part # T20BTR-6048 is a Dexter axle that we carry with a spring-center that measures 48", a hub-face that measures 60", and a weight capacity of 2,000 lbs. It is compatible with hubs that have the bearing # L44649 for both the inner and outer bearing. You may have trouble finding a hub that fits these specs and is compatible with the 6 on 5-1/2" bolt pattern that you are wanting to use so you might be better off looking at custom axle options.

We also have some axle-less suspension options available that you may be interested in. The Timbren systems, like the Timbren Heavy-Duty Axle-Less Trailer Suspension # ASR35HDS02 is a great option to consider since it eliminates a lot of the technical and intricate details that a typical leaf spring setup requires. I have attached a sample installation for this system that you can check out.

expert reply by: Jon G

click to enlarge

7/17/2020

How much space is needed between the back of the hub and the trailer. How far does the wheel or tire extend beyond the back of the hub, on average of course

Chris R.

7/21/2020

You should have at least around 2" of clearance between the tire's side wall and the trailer frame. A little less than half the tire's width will extend past the back of the hub.