Spring under or over axle?

[tclaremont]

New member looking for insight.

I have a 4 x 8 trailer that is very heavy duty. 2 foot tall steel sides. 4 foot tall Drop down tailgate that serves as a ramp. Home made, so I cant tell you too much about it. I will be towing it behind my Jeep JK.

When I got it, it was a spring under axle arrangement, and it sat ridiculously high in my opinion. It was on a homemade axle with motor home wheels, so I have ordered a new 3500 lb axle for it so I can use 5 on 5 wheels that match the JK.

I am tempted to set it up as a spring under axle strictly for height reasons, but I am wondering if there are things to consider that I am not aware of.

What is your thought process for deciding between the two? Strictly height and ground clearance, or is there more to consider?

 

[Titanpat57]

Well first off welcome aboard!!

I hope you don't catch the trailer bug like so many others here...we've lost some good , sound folks, to total trailer fanaticism :ylsmoke:

I think for an axle standpoint a few things come onto play, first one being why have a trailer with 10" more ground clearance than the Tow Vehicle?

Do you want or need to match the TV that's lifted? Is this a work and play trailer, or strictly play? I personally like a SUA...but couldn;t do it on the current build without a whole bunch of craziness.

I think another thing to consider is many guys get rid on the stock 3500# springs and opt to use JK front springs, I may be off on the Jeep model, but I've seen it done several times.

Post up some more about, and pictures always help.

Good luck, Pat

 

[Hill Bill E.]

I think another thing to consider is many guys get rid on the stock 3500# springs and opt to use JK front springs, I may be off on the Jeep model, but I've seen it done several times.

I think you're thinking of YJ springs. (2 1/2" wide leafs) the JK's are coils front/rear.

If you don't need the height, spring under should be fine.

Either way, the axle tube itself will be the low point.

I went spring over (on my M416) for 3 reasons:

1: Run same size tires as my Jeeps (becuase I use the best 2 old tires for the trailer, when the Jeep gets new shoes):coffeedrink:

2: Get the trailer tongue the same height as the Jeep(s) hitch. (don't need a 'drop' hitch)

3: Get the RTT up a bit. It's not tall enough to walk under, but it's just right for sitting under it. Nice for shade or the rain.

Now this is on my home brew "Adventure Trailer", and while it rarely sees the trail, it was designed with towing on trails in mind.

On my 5x8 cargo trailer, and other M416, I left them spring under.

 

[tclaremont]

Here is the way I bought it. It took all of about six minutes to rip the plywood off. It is hard to tell in the first picture, but it really sits higher than it appears. It was used by a roofer who threw the rubbish in the trailer from roof tear offs, etc. The tailgate is not evident in either picture, but it is four feet tall and therefore sticks up twice as high as the sidewalls of the trailer. Since the tailgate is diamond plate, I am sure it adds quite a bit of tail weight back there, too.

This is the direction I am heading:

The bed itself is four by eight. The tongue is pretty long, so it makes for a longer trailer than I would like, but I will run it for a while and see if I am compelled to shorten it. The bed and side walls are steel, so the trailer is pretty heavy. Probably not the ideal setup, but I have a long way to go before I am upside down it in.

 

[tclaremont]

Here is how it looks tonight. Axle is on order. Should be here next week. At that point I will remove the fenders, see where the tires wind up, and mount new fenders. Probably should have done that before I mounted the jerry cans... huh?

 

[Titanpat57]

Here is how it looks tonight. Axle is on order. Should be here next week. At that point I will remove the fenders, see where the tires wind up, and mount new fenders. Probably should have done that before I mounted the jerry cans... huh?

Hell no!!!!!!


Mods wait for no man!!



Mod em' if ya' got em'..........


Um..small side note...

The small picture above showed blue...did the paint store mess up?




Looks like a nice size, can't wait to see the finished product.


Pat

 

[tclaremont]

LOL.

The first small picture with the wood sides is the way I bought it. The second small picture is a copy of the first, but the wood was photoshopped out (you can still see the wood, it looks like a fence) and the Jeep wheel and blue paint was photoshopped.

The third, most recent picture is after I hit it with a grinder and threw some paint on it.

 

[tclaremont]

I picked up some JK wheels to match the Jeep. I also got a spare tire carrier from a JK and mounted it on the side of the trailer.

I needed to weld both spring hangers on one side. I think the previous owner curbed it or something.

New axle was delayed but is enroute. It is scheduled to arrive on Monday.

I am holding off on the fenders until the axle and wheels are mounted.

 

[Hill Bill E.]

Is it just my bad eyesight, or is there no shackle on the spring?

Looks like the same style mount, front and back. (but my eye's aren't that great!):snorkel:


Also, for a smoother ride, you might want to look into a longer spring.

Those are not only short, they have a lot of leaves, which equals a stiff, bouncy ride, unless there is a lot of weight in the trailer.

 

[tclaremont]

The trailer was previously set up for a lot of weight. I realize that I will probably have work to do on the suspension, but I cant really make those decisions until I get the axle mounted and see what happens.

I have shackles and will install them this weekend before the axle gets here. Previously it did NOT have them.

 

[Ford Prefect]

You know, I like a nice long tounge. I have seen them off road with both, but from watching them it seems like the long tounge works better. As for the Over Under. If you are not planning to put shocks on it you really do not (that I know of) find any difference in the over v under except height and tire size.

I did mine OVER because I have tiny tires on there, and until I can afford a new axle and wheels/tires, it is going to need the ride height.

As for a trailer a touch taller than the jeep, I actually think that is a very wise idea if you are thinking more large rock. That way you do not have to pay as much attention to where you place the trailer, however if you are thinking more sand and flat roads then go lower, because trailers flip over a lot in off road situations, therefore you you keep your stability down.

Anyhow, thanks for reading the seemingly mindless dribble of a guy who knows little.

Cheers

 

[Hill Bill E.]

I have shackles and will install them this weekend before the axle gets here. Previously it did NOT have them.

Wow! It must have really rode rough!:Wow1:

Leaf springs from a YJ work well (fronts) they are long enough to be smooth, heavy enough to carry a load (have to figure the motor, frame, front clip, etc. The front of a YJ is carrying easily 1000#'s + )

And they have a nice spring rate, so they aren't quite so bouncy.

 

[tclaremont]

A combination of short springs, many leafs, lack of shackles, and mobile home wheels and tires made for a less than spectacular ride, for sure.

 

[tclaremont]

I got the axle installed today. I should have ordered the axle about one inch wider. I may need wheel spacers because the tire ever-so-slightly rubs on the front spring shackle bolt. Maybe I can use a different bolt.

I had to rip the old fenders off, which did not disappoint me. They rubbed on the tires with the axle over the springs.

It sits pretty well when hooked to the JK. The low trailer will not allow for much off roading, but the lower height has its advantages, too.

Any suggestions for fenders would be appreciated. I think I like the idea of a flat topped fender more than a round. Everything else in the picture is pretty boxy, so adding a round fender might seem out of line.

 

[tclaremont]

I got some diamond plate, flat top fenders. I will weld them on, but what rule of thumb should I use for mounting height? Three inches of space between tire and fender? Six inches?

With the current spring setup, there is NO wheel travel up and down, so I guess this is going to be a matter of aesthetics!