Single Axle Trailer Design

Hey Y'all, I am thinking about building a new trailer for hauling my TJ and LJ. I currently have a 16' tandem axle trailer with 2 3.5k axles and I have been having problems with its reliability. Most recently I bent the front axle on a trip to Utah which caused the tires to wear on the inside causing a blowout again. I have also been having bearing issues where the bearings are constantly loose and needing adjustment. I looked at 10k trailers here locally and they are $6-7K plus the taxes and have to be custom built. The other issue here in Texas is a 10k trailer needs a yearly inspection. An annoyance by any standard. I also wanted to go shorter, but the custom builders won't go shorter than 16' for a 10k. After all that research I landed on building my own trailer. My current tandem has geometry issues with the suspension and the equalizers that put more pressure on the front axle. That is the likely cause for the bending IMO. I wanted to avoid those problems with this build along with being shorter than 16'. I'm planning on running a Dexter 10k oil filled axle with dually wheels. The frame I laid out with 2x4 rectangle tubing that is 3/16" thick. The deck is 2x2 3/16" square tubing and the runners are 2x6 wood. The deck is 12' long and 88" wide and underslung of the frame rails. I have the axle already and am in the process of collecting the rest of the parts. I thought I would post it here before I ordered the steel and wood in case someone can see an issue I haven't. TIA.

3jeepfan said:

Nice, but you should check out this for ideas. https://wranglertjforum.com/threads/single-axle-crawler-hauler.77912/

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I had read through that thread. Nice build.

Steel showed up today. Another step closer to getting this thing rolling.

sierradmax said:

Any progress? Did you design the trailer around your jeep or any other rig(s)? Your trailer will be significantly higher than the one I built. What provisions do you have for ramps? Also, what do you plan on doing for a finish?

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A little bit done. Some of the frame is cut and tacked. The deck should be about 20" high. I am building some aluminum slide in ramps for the rear. I'm probably just going to go the implement paint route.

sierradmax said:

Any reason why you left the rectangular tube long in the front? Are you going to pie-cut and bend them to make up the rails for the tongue?

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Yeah, I already cut them down and pie cut the inside to fold them in.

I made a slight design change on the fly with the tongue. I had a nice piece of 2x4 left so I made a center beam for the tongue. It should help strengthen the tongue.

sierradmax said:

I did similar. Helped lengthen and strengthen the tongue. FYI, a little more tongue weight is good for these single axle trailers. I splurged and bought a weigh-safe hitch. Peace of mind knowing proper load positioning. Besides, I tow with a 2.8L colorado duramax and a 6.6L sierra duramax. Both have different tongue weight capacities.

https://www.weigh-safe.com/ball-mounts/

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I did quite a few weight calculations regarding tongue weight and axle placement. A guy can really go down a rabbit hole between that and tongue length. Ultimately it's not as big of an issue for me. I pull with a 4 door 2500HD Duramax and my 30' class C motorhome. Neither care about the tongue weight of a small trailer and Jeep.

Update, a few more parts installed. I also tacked up the axle mounts and test fit the axle. Looks like the deck is between 20 and 21 inches high. There is more clearance between the axle tube and frame than I calculated. Not entirely sure where I got off there. No big issue more clearance actually works in my favor.

sierradmax said:

I think clearance for my trailer is something like an inch and I have around 1.5" between top of tire and the fender. Those leaf packs barely compress with the weight of my Jeep on the trailer. You could always add lowering blocks if you think the trailer sits too high.

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I think the Dexter spec for my setup is 1.9" for the bump stop to the frame. I'm probably closer to 3 inches right now. That's a good idea on the lowering blocks. I actually thought about shortening the spring hangers before I welded them on, but ultimately decided that wasn't the fabrication rabbit hole I wanted to go down over an inch.