How narrow is too narrow?

[computeruser]

Before too long I'd like to finally set to work on building a camping trailer, since camping with a spouse and three dogs (granted 2 are pugs) is asking more of the interior space in my Jeep TJ than it can really provide. I've seen all the designs on the market, and if money and space were irrelevant, I know what I'd be buying. But money and space are relevant, so here's my situation.

I want to design and build a trailer that can nest inside my existing utility trailer when not in use. Interior dimensions of my existing trailer are ~8' x 59.6". I'm planning on duplicating the tube-in-tube removable/adjustable tongue design that was posted on here a while back, so I don't foresee the length being an issue. But the width is my concern. I'd love to have the identical track width as the tow vehicle, but I have nowhere to store such a trailer right now. So I'm kinda stuck with the nesting trailer idea.

I had hoped to be able to run the same 31-10.50-15 tires and rims as the TJ, but when I start playing with the width numbers I don't get the sense that I'll have a lot of left-over width for the frame when tire-to-frame clearances are figured in. Maybe a 34" frame width, and even that would be fairly tight. If I went with 215-85-16, I could probably gain back enough clearance to have a 38" frame width and adequate clearance, and still have a tire that could double as a spare for the Jeep if I could find (or have made) an appropriate rim.

Alternatively, I could run a shorter narrow tire, like a 215-75-15, at the expense of tire interchangeability. I really don't foresee axle clearance being a problem in any of the places I anticipate traveling, so the shorter tire wouldn't be the end of the world. But I'd then have to buy three trailer-only tires, and still carry a spare or two for the tow vehicle.

I'm still uncertain about springs, but they will be leaves and will have shocks. They may or may not be setup spring-over. CJ or YJ leaves, minus a leaf or two, would probably be best. But lighter-load standard trailer springs with shocks would be easier/cheaper in the short run, and trailer spring hangers/shackles could be more easily affixed to a 2" wide frame (whether c-channel or box).

This trailer would be used primarily to transport camping gear, food/clothing, vehicle (and trailer?) spare tires, and possibly a RTT in the future. I suspect that 5-700lbs would be the absolute maximum load that the trailer would see, and it would usually be much less than that. The trailer would probably see 75% of its use on paved roads, and only 5% in truly "off-road" circumstances.

So here are my questions:

1. Is there anything inherently bad about having a <36" frame width, apart from less width to overcome the forces attending a relatively high COG?

2. Is there anything inherently bad, beyond the obvious instability of a high COG trailer, about running 31-10.50 tires on such a narrow trailer?

3. On such a narrow trailer, would you trade a lower COG for non-interchangeability of trailer tires?

4. Assuming that overall trailer weight never exceeds 1200lbs, would you think that trailer springs would be "good enough," or should I go the distance and run CJ/YJ springs? I think I know the answer, but the % increase in price may or may not pass the spouse test for a purely recreational, frivolous trailer.

 

[Renrag]

I'm a lurker here mostly.

Any reason you couldn't build the trailer to the same track width as your TJ and use space saver spares on it when storing inside the other trailer? I know, not ideal, but the trailer you could build might be a better overall unit in the end.

mikE(random mind dump)

 

[Martyn]

Renrag has offered a good solution, if you had bolt on fenders those could also be removed to narrow the trailer down.

Try to keep your track width slightly narrower than the tow vehicle by a couple of inches. This will help when making tight turns if the trailer wants to cut the corner.

Short trailer springs are not very compatible with off road trailers. Look for something at least 36" eye to eye.

Go with 3500 lbs bearings.

 

[stick]

Another vote for something you can take apart easily for storage. Something that you can take the fenders off of and put smaller tires on so it will store inside your other utility trailer.

 

[computeruser]

Thanks for the input, all. Sometimes the easiest solution is sitting right there...and gets missed. Even though it requires an added step, I suspect it's worth it in the long run.

Now to spend a bit of time with a pen and some graph paper...


EDIT: Any suggestions on good spring choices? I know folks have used used YJ Wrangler springs, but is there something else that would be better or require less playing with the leaves to get a good spring rate?

 

[stick]

Most tractor supply type stores have trailer parts, including leaf springs. YJ or CJ springs would be okay, but they'd be pretty stiff for a trailer. You'd probably have to take a leaf or two out of the spring pack. The leaf springs that Tractor Supply Company sells might be a good choice since they're for utility trailers.

Here's a link to the Tractor Supply Company site. They sell all kinds of trailer parts including leaf springs and fenders:
http://www.tractorsupply.com/webapp/wcs/stores/servlet/DisplayCategory_10551_10001_131301_14338__14297|14337|14338

But then again, maybe I'm totally wrong. I've never built my own trailer before

 

[ExpoMike]

EDIT: Any suggestions on good spring choices? I know folks have used used YJ Wrangler springs, but is there something else that would be better or require less playing with the leaves to get a good spring rate?

Ah... the $100 question. In most cases, the longer the spring, the better it will ride. A shorter spring (like most trailer springs) has to have a higher spring rate to keep the load capacity but because the leverage points are shorter they tend to resist flexing. A lot of things can factor into this, such as shackle length. A longer shackle will make a spring ride softer then a shorter shackle.

Most trailers are made for load capacity and not ride quaility. This is where airbags have a major advantage as the spring rate can be changed depending on air pressure. Now airbag are not completely a simple thing as different diameters of airbags will react differently to air pressure and you have to find the right one for your use.

I for one, if I end up staying with leaf springs, am going to use the stock ones off my Cherokee and tune with removing leafs. This assumes I don't go with some type of airbag system, which is really tempting.

YMMV. :coffeedrink: