"Wingin' it" 4x6-ish Trailer Thread

[nnnnnate]

I bought some tube on Saturday after hemming and hawing all last week about how much I needed to get this thing going. Then, while putting off actual work today I read a couple more build threads from EXPO and decided to alter a couple things. I need to get this thing going though because I want to be done with it before things warm up more than they already are. I'm an unapologetic fan of Adams trailer and he has been very graceful to answer a lot of my questions that I've had about it. I like that his trailer started basic and can be used for yard duty as well as camping. I don't want mine to be a one trick pony so my trailer will evolve over time but whatever it turns into its going to have to be able to have an open top for mulch trips and to be able to get a tree home from the nursery.

The plan is to build a 4'x6' box with some additional room up front for fuel and water. I'd like to get a water container at some point with a hand pump (much like whats offered by Adventure Trailer) but I can schlep 5 gallon jugs for now. I'm going to use 2.5"x2.5"x 0.120 wall tube for the frame. (I'll fill in the "steps" in front and behind the wheels with smaller tube, the hitch will be beefier.) The sides will be 24" high with a top rail and eventually a removable lid that can somewhat seal out the dust. I've got some extra stock JK 5 spoke wheels with the 255/75/17 BFG MTs which I'll be using. I'm planning on a 3,500# basic axle from Henderson with leaf springs.

Here is a real basic sketch of what I'm thinking about for the frame layout.



I'm going to be asking a ton of questions here and hope it won't get too tedious for you guys. Everyone has been great with helping out up to this point and I really appreciate it.

I could use some guidance on how to figure out how wide of an axle to order. I'd like it to track with my JK and if I remember right the JK axle WMS is 62". The interior box measurement is 48" so outside will be 53". Is 4.5" from the edge of the trailer to the hub on each side enough clearance? I'm not sure what the terminology is so if I'm not explaining something correctly or if I'm being unclear please let me know. Is there anything else I need to look at before I order the axle?

Thanks.

EDIT: 62-53=9 not 11. math

EDIT 2: I had bad info, the actual WMS of the JK axle is 65.375". (Future reference)

	quantity	product	unit price	amount
Metal Mart	2	2.5"x2.5"x0.120x24'	45	90		main frame
	2	cut	2	4
Triple S	1	2.5"x2.5"x0.238x6'	40.5	40.5		receiver tube
Henderson	1	3500# axle idler hub	186.48	186.48		axle
Discount Tire	2	mount & balance tires	13	26
SpiderTrax	1	1.75" 5x5 spacers	89	89		wheel spacers
Wheels	2	JK stock wheels	0	0
Tires	2	BFG MT 255/75/17	0	0		WC member
Triple S	3	1.5"x1.5"x12' 14 GA	15	45		vert sides
	1	2"x2"x20' 14 GA	36.64	36.64		top box rail
	2	48"x120" 18 GA	51.56	102.92		box sheet
Midnight 4x4	2	2.25"x12"x0.375" DOM	12.75	25.5		axle sleeve
State Trailer	14	Tie Loop	0.69	9.66
	2	Spring Bushing	1.04	2.08		For rear spring perch
Wasatch Steel	1	Reciever Coller	5.97	5.97
E-Trailer	2	Fender 13"x36"x20"	44.95	89.9		extra wide
	1	Swivel Jack 15" lift	42.95	42.95		tongue jack
			total	796.6

 

[UNSTUCK]

You need to know the backspace of the wheel you are using. That will tell you how far in the tire will be and then you can figure how much clearance you will need. I think your wheels have more than 5.5 inches. So the tire will rub on the frame.

 

[sixstringsteve]

subscribed and looking forward to this. I'm at least 6 months out on my trailer build. That way I can learn from your mistakes.

 

[Brian P]

Good luck!
I almost melted the brain of the axle guy when I was building mine.

 

[nnnnnate]

You need to know the backspace of the wheel you are using. That will tell you how far in the tire will be and then you can figure how much clearance you will need. I think your wheels have more than 5.5 inches. So the tire will rub on the frame.

Good stuff.

I screwed up my math so I edited with the correct numbers. It looks like backspacing is 6.25" on the stock rims I have. I'm running 1.25" spacers on my Jeep so my actual rear axle WMS is 64.5". Pushing the trailer axle to 64.5" to match what I actually have on the Jeep (with correct calculations...) would still only give me 5.75" and doesn't work. I guess the options I have are to extend the axles to fit the tub size I want or shrink the tub to fit the axle size I want. I'll have to do some searching to see what the negatives are for having different track widths but I can't imagine that it'd be horrible for the couple inches I'd be needing.

How much clearance do I want from the tire to the tub?

subscribed and looking forward to this. I'm at least 6 months out on my trailer build. That way I can learn from your mistakes.

I'll be happy to expose them! Lets start with MATH....

 

[UNSTUCK]

How much clearance do I want from the tire to the tub?



How much flex to you anticipate the axle having? If you were to solid mount the axle to the frame, you would need a very small gap. If the tires will stuff way in the wheel well, you will need more space. I would think some of the trailer owners will have good number for you.

 

[zmotorsports]

Subscribed. Love a trailer build thread.

I too just ordered my axle from Henderson but I went the torsion style because it won't see off-road. Like already mentioned, the basic measurement you need is the hub to hub width. With a spring axle the mounts are negotiable once you get the axle. For my torsion axle I had to know the exact mounting location width in addition to the hub width.

Looking forward to seeing your trailer come together.

Tire to frame or tub distance will depend on how much flex it will have. Being a 3500 pound axle, it may not have too much as those spring packs are fairly tight. On a normal trailer for street use I like to keep a minimun of 2.5" clearance from the inside of the tire to the actual trailer.

Mike.

 

[boogie_4wheel]

4x6 with a 3500lb axle? The axle and 2.5"sq tube sounds overkill for this small of a trailer.

 

[Brian P]

4x6 with a 3500lb axle? The axle and 2.5"sq tube sounds overkill for this small of a trailer.

IIRC, a 3500# axle is needed to get a 5 or 6 lug hub.
2.5" tube might be overkill, I was told the same thing when I built my trailer, but it has held up great over the last 5 years.

 

[nnnnnate]

I stopped by Henderson on my way home and got a bit of information. They guy wasn't a talker so I didn't ask too many questions but I think I'm going to narrow the outer dimensions by a smidgen to try and keep the tracking as close as I can to the JK. I'm running 1.25" spacers on my rig and it appears I'll need to run them on the trailer as well to make the axle hub centric. The boards say I'll need at least 1.5" spacers.

This part seems like it could go a fair amount easier if I just built the basic box then figured out what axle I needed but I want to make the "bumper" extend on both sides to start the framing of the steps and fender flares. Because of this I don't want to cut them too short. I did find another guy that seems to have built the same base I'm wanting that extended his rear cross member 14.5" past the tub on both sides. He was still a little short and ended up adding a plastic lip around the fender flare.

 

[jeeper]

Why have you gone with the idea of boxing the tires in? What benefits vs drawbacks did you weigh?

 

[nnnnnate]

I figured I'd box them in to use it as a step, could also use the area to mount fuel or water cans. I'd also tie them in to the fenders for rigidity.

I don't really see drawbacks for boxing them in, I don't plan to rock crawl with the trailer so I don't think the extra width the whole length of the trailer would be an issue.

What am I missing?

 

[UNSTUCK]

I stopped by Henderson on my way home and got a bit of information. They guy wasn't a talker so I didn't ask too many questions but I think I'm going to narrow the outer dimensions by a smidgen to try and keep the tracking as close as I can to the JK. I'm running 1.25" spacers on my rig and it appears I'll need to run them on the trailer as well to make the axle hub centric. The boards say I'll need at least 1.5" spacers.

This part seems like it could go a fair amount easier if I just built the basic box then figured out what axle I needed but I want to make the "bumper" extend on both sides to start the framing of the steps and fender flares. Because of this I don't want to cut them too short. I did find another guy that seems to have built the same base I'm wanting that extended his rear cross member 14.5" past the tub on both sides. He was still a little short and ended up adding a plastic lip around the fender flare.

I guess I don't understand what you are saying. You want to narrow your axle width and then add spacers to make it wide again? Also, maybe I'm misunderstanding "hub centric". That should describe at type of wheel that is centered by the hub. Your jeep wheels are lug centric, in that the lug nuts center the wheel to the hub. And I'm not sure what any of that has to do with selecting your axle width.
If your outside frame measurement is 48" and you want 2.5" of tire clearance, and you have 6.5" backspace, you should get an axle that is 66" wms-wms. I'd avoid running wheel spacers at all cost.

 

[nnnnnate]

I thought I had read that the JK rim won't fit on the trailer axle because of the bulge in the middle of the hub. I'd prefer not to run spacers on the trailer too but thought I would have to. I'm probably wrong about that but I'll have to read more to be certain.

 

[UNSTUCK]

Ah, the center hole of the wheel may be too small to fit over the hub. Gotcha. I'd still rather machine the hole larger (hand held machine, if need be) than run spacers. It's just a pain to check torque on the lugs of spacers, and they must be checked VERY often.

 

[CobraNutt]

I had to run spacers (1.25") AND work the inside of the wheel just a smidge to get my matching Renegade wheels on my trailer. Not ideal, but it works just fine. Yes, you might need to check the lug nuts a bit more of often, but mine never backed off at all with my spacers last year. Loctite helps, and is even supplied with the Spidertrax sets.

Sent from my mystical handheld gizmo.

 

[nnnnnate]

I found a pretty decent explanation on the issue I'm likely to run into using the stock JK rims on the trailer axle.

Fitting Jeep Factory Wheels on Typical Trailer Hubs

Here is a less technical thread from EXPO

I wasn't sure if this was an issue that many vehicle rims would have but Adam doesn't have this issue on his trailer so it must just be a Jeep feature. I don't really have an issue running spacers (I am running them now) but I'd rather not unless I have to. Especially since I'm having the axle built to spec. Josh suggests milling out the rim to fit but I guess the issue I have with that is how to deal with spare tires. I'd like to be able to swap any tire on my setup to any other location on the setup whether its on the trailer or not. I may be overthinking this but if I have to add a spacer I think it'll be worth it to me in the long run.

 

[sixstringsteve]

Toyotas have huge hubs, so their wheels require a big center hole. I'm betting that's why Adam didn't have this issue. You could mill ALL your wheels (unless they're hub-centric on a jeep)

 

[Box Rocket]

4x6 with a 3500lb axle? The axle and 2.5"sq tube sounds overkill for this small of a trailer.

Definitely NOT overkill if it's to be used offroad. There are many cases of trailers this size using smaller 2000# axles breaking spindles and bending the smaller tubes. While the trailer may not ever have that kind of load in it, if you use it in rough terrain, and especially at a decent rate of speed, then you'll want the larger axle.

 

[Box Rocket]

Toyotas have huge hubs, so their wheels require a big center hole. I'm betting that's why Adam didn't have this issue. You could mill ALL your wheels (unless they're hub-centric on a jeep)

This. I've always had Toyota wheels on my trailer so I never ran into hub clearance issues.
.