My trailer build - I need help with trailer supplies...

[The Adam Blaster]

Hey everyone!
I'm getting pretty serious about my plans for a multi-use trailer build, and the friend (Randycj7) I'm getting to build it may be ordering parts in the next week or two, so I need some help.

I need to find a supplier for heavy-duty air struts.
The main box on the trailer is going to be a bit larger than 4'x8' and will have a hard, removable, hinged and locking lid. My idea is to have a semi-domed shape to the lid to help with roof loads, especially snow.
It's going to be fairly heavy with that size, and I'm going to want heavy duty, and quality struts.
I have no experience with how to choose the proper size and load rating compared to the load that is actually being lifted.
Example: If the roof is 100 pounds do you get 2 struts that are 50 pounds each, or 75 pounds each for that extra ummph? <-- I have no idea, help me out on that one.

Also, I have read multiple times that the standard trailer leaf springs are too short, pretty stiff and not at all ideal for navigating trails. Where can I get (order) some longer leaf packs that would be appropriate for this build?

I'm going to have the essentials built into the trailer this spring/summer and then add on accessories later as I actually use the trailer for more than just carrying garbage to the dump, and building supplies for the house.
I will probably be adding to this list as I go, but here are the details on the trailer that I can think of at this point:

52" x 100" interior dimensions of main box (maybe even wider?)
Hinged, removable, locking domed roof
Tailgate on rear, will be full width to be able to slide in sheets of building materials through the rear
Receiver hitch protruding slightly from rear frame/bumper for bike rack later, or maybe just accessory carrying rack? I don't know, but I know a receiver is mighty handy.
There will be a 2" lip on the top edge of the box where the lid meets it to help create a nice mating surface to be easily sealed against the elements, and there will be heavy duty clamps to tighten the lid down.
LOTS and LOTS of interior tie down hooks - I'm actually thinking that I could make a two-tier type of storage inside the main box. Attach a full size webbing just under the inside lip of the box and toss light stuff in there, and it would all sit just under the domed roof. An idea for later.
Small "hatch" on passenger side front to access fridge slide later (24"W x 26"H this is under review) I won't be buying a fridge for a while, but I need to build this in to the structure at the beginning so it's there when I need it later.
Solidified - 24"W x 26"H
3500# axle with electric brakes - 5 on 4.5 bolt pattern to match XJ
Removable/extend-able tongue
The fenders will extend fore and aft of the wheel wells to create platforms to mount accessories onto, like spare tires, propane tanks etc. I'm going to need tie down locations on these platforms as well.
No side boxes for now, but I want to build in the ability of the sides to have mounting locations, whether it be a removable table, or to mount small boxes later. I suppose this could be achieved with some captured nuts welded into the vertical wall supports? Any ideas on this aspect would be helpful too.
It will have a decent sized platform right in front of the main box as well, this will house a large nose box later on, as well as jerry cans. The nose box will eventually house some batteries and electrical components, as well as some straps and tools.
I'm planning on having the side walls be about 30" tall - maybe even 32". This is very dependent on the overall size of the fridge and slide combo that will protrude out of the hatch. I would be looking at the mid-sized fridges, approx. 60L size, and the size of the end is approx. 20"Wx22"H. I'm not sure how much a set of slides would add to the overall width and the height. Help on this as well?

One other design feature that I want to have incorporated, is the ability to stand this trailer up on it's tail for storage.
It's going to need some semi-circle protection bars at the rear corners that extend past any other portions of the tail end, except maybe the bumper, and actually, they could/should probably be attached to the bumper...
I'm thinking that I could rig up a winching system to pull on the tongue to raise it to a vertical position and sit on it's "butt" if I have a long section of time that I won't be using it.

And because I'm planning to have the trailer built back in my home town of Windsor, Ontario, and then tow it back to Alberta with my minivan, I'm going to start off with small trailer tires, probably 205/75R15's and later move up to 31's or 33's to match one of my XJ's wheel/tire options. I figure the smaller and lower the trailer being towed behind the van, the better. And I get smoking deals being employed in the tire industry, so I'll treat myself.

One important question I'd like advice/opinions on - placement of the axle.
Given that the overall length of this trailer is going to be 13-14 feet from tip to tail, should he axle be dead centre of the main box, or slightly to the rear?
If I mount the spare tires behind the axle on the rear platforms, and then the jerry cans beside the tongue box, would that balance everything out for the most part?

Anyways, I haven't bought a thing yet, so please throw out any and all comments, suggestions or criticisms that you think I need to hear!

And thanks for reading!


EDIT JUNE 21 '11 --- I just want to put an update in here with everything that I've actually finalized up to this point since Randy is going to be hopefully getting started on it this weekend.

Main box outside ~ 56" x 104"
Main box inside ~ 52" x 100" (I want to make sure that the interior will not be too tight when loading 4'x8' sized building materials)
Long and wide tongue platform - enough to accomodate mounting 2 full sized spare tires (33's) in a vertical position right in front of the main box, along with a large tongue box in front of them, and also long enough to jacknife the trailer and have full access to the rear of the tow vehicle.
Axle dead center of the main box - with the extra weight and length of the tongue, I think this placement will be the best.
Sidewalls of main box = 30" high.
Side hatch = 24" W x 26" H and this opening will begin 2" above the floor of the main box.
Side step/platform width = equal to width of fenders but at least 8" wide to accomodate jerry cans.

 

[randycj7]

So now I have to get to work on it I suppose.

 

[MOAK]

4x8

Sounds like you have considered most everything. When I built mine up I centered the axle on the box. Also am using a 360 degree pintle hook for full articulation. The larger question looms in my mind. Why an 8' box? Mine is 6 ' and has better approach & departure angles than my rubi. 33s on the rubi & 31s on the trailer..

 

[The Adam Blaster]

So now I have to get to work on it I suppose.

Ya, once it's in writing, than you (we) are committed! lol


I want an 8' box because this trailer is going to see a lot more action carrying building supplies than it will see trail duties within the next few years, so I'm designing it around what it will be used for most.
And the maiden voyage will be 3000km from Windsor to Alberta carrying back a bunch of tools and stuff that is sitting in the garage behind my rental property that I still own in Windsor. I have a significant amount of stuff I want to bring back with me, and the larger box will help with that. I don't know if I'll be able to bring back my 60 gallon vertical compressor, but I should be able to grab my stand up drill press - that's something I've been missing out here since I moved 5 years ago!

 

[Paladin]

If you're doing the 4x8, I would suggest the axle centerline be at least 6" behind the center of the box. I can do the math for you if you want, just let me know what kind of loads you want and what kind of tongue weights you want. There's always the 10% rule but I don't follow that rigidly.

It sounds to me like you have similar requirements to the second trailer I want to build. Might I suggest you consider a 50"x72" box with 24" wall height. Make the tailgate full width, and support it with cables just like a pickup truck. Then when you want to carry 8' building materials, drop the gate and leave it hanging flat with the floor. Just like a pickup truck.

I have Autocad drawings already...

For leaf springs, maybe just look for Jeep leaves? Maybe even say... from a CJ7? Suggest comparing the rear axle load rating of the Jeep to your intended maximum trailer weight, see if you can get a match.

 

[The Adam Blaster]

I had thought about the 6' length at the beginning of my design ideas, but I went back on that and again thought about the majority of use it's going to see - hauling stuff in town. (And across the country as well...)
I would really rather have the tailgate closed with the materials inside. I like this idea because I could park the trailer full of stuff and just leave it safely locked. Also, it's much safer to carry the load completely contained when/if I use it for hauling larger items down the highway. My wife's parents live about an hour away, and I could see using it to help them carry something to or from their home on occasion.
The other issue I thought about with a slightly longer trailer - the longer outside walls allow more materials, more "things" to be able to be attached to the sides.
Just in the last day or so I've gone back and forth on where to store the tires and jerry cans separately. I thought first of mounting the tires just behind the wheel wells, and the jerry cans between the tongue and main box.
But then I changed my mind as the tires (whether it be 31's or 33's) would be heavier than the jerries, and the heavier load should be out front right?
Plus aesthetically, I think the tires sitting flat against the front of the box would look pretty cool, and they could be unlatched and roll off the side when and if they are ever needed.
If the tires are mounted to the side of the box, I'd have to "lift" them off their holding pins and lower them to ground level - harder for me with just one arm...
That's it, tires in the front! :victory:


The idea with the fridge sliding out of the front passenger corner is to create a kitchen area on the passenger side of the trailer. Add a table that attaches to the side and you've got a readily available fridge that opens right beside your work station and where your stove sits.
And that's also why I'll need the side walls at a minimum height - to allow the fridge the needed room to slide between the lower main frame structure (the floor of the trailer) and upper horizontal support.
And thinking about this kitchen setup... It would actually be nice to have a double-slide with the fridge. The fridge would be held on the main heavy duty slide, and then a secondary slide with a small shelf could be attached underneath and slide out to provide another surface to hold objects such as that cold drink you just pulled from the fridge.

 

[The Adam Blaster]

I have Autocad drawings already...

For leaf springs, maybe just look for Jeep leaves? Maybe even say... from a CJ7? Suggest comparing the rear axle load rating of the Jeep to your intended maximum trailer weight, see if you can get a match.

Oh, and I'd love to see those drawings, so far I have some very rough sketches of the frame and front platform/tongue structure I did while was at work, while I was supposed to be... well, working... :coffeedrink:

Regarding the leafs, I need to go back and search this sub-forum.
I was following a few builds and I am now thinking I asked this already, and Jeep leaf packs came up...

 

[The Adam Blaster]

I knew I had asked somewhere...

From Chasingdreams' trailer build thread, post# 61:
http://www.expeditionportal.com/forum/showthread.php?t=54859

The item # that I see listed on the Invoice from Quadratec for the springs is 16203 020

I'll likely use those same ones as they are proven to work well.

 

[Paladin]

Not complete, but here you go:

I set the axle well back so that it balances in 4x8 mode. The tongue weight will be high, but no huge deal for typical camping loads. Only problem would be if hauling dirt or firewood in the 4x6 mode.

One could even do like a "bed extender" just like a pickup as well. Just saying, an 8' trailer is really big for offroading. (yeah, like I should talk...)

From my experience... I *have* a 4x8 trailer right now, and I use it a lot. However, if I had the time, I'd build the 4x6 and sell the 4x8.

 

[Scoutman]

Check out McMaster Carr's website. They have a section on their Gas Spring pages that tell how to properly spec out and mount gas springs for your lid lift application.
http://www.mcmaster.com/#gas-springs/=bujej6

 

[SWITAWI]

Subscribed, Adam! Since my project is still collecting dust I'll be living vicariously through you for the time being. :sombrero:

As for the question of axle placement... You going with a 4'x8' box, but what is the planned overall length? I can see the axle more likely being centered on the dimensions of the load box itself in the case of a 'utility' trailer for reasons of balance during maximum loading capacity. It might prove squirrely with a short drawbar, but would okay if further away from the hitch point. That's been my enduring idea for my multi-use trailer because I plan to have an extended platform out in front of the load box.

 

[Paladin]

No, for a utility trailer, the axle must be set back a little bit, so that the tongue load builds up as load is added evenly in the box. Otherwise, say if you have 50lbs tongue load with an empty trailer, axle centered, but as you add load the tongue load does not increase. You could have 3000lbs in there with still only 50lb tongue load.

On my big camping trailer, I did center the axle, but I knew I would be loading way more stuff in the front, and the rear is mostly empty sleeping quarters. I also made the centerline of the water tank about 6" ahead of the axle. That way as I load water, it adds a little to the tongue weight.

 

[JeepFreak21]

I'm not sure how much a set of slides would add to the overall width and the height. Help on this as well?

Accuglide makes some REALLY heavy duty slides that can be mounted under the drawers if you don't have room on the sides. The maximum capacity goes down significantly, but may still be sufficient (150lbs+). I found a pair on eBay for $40 that are perfect for my build.

One other design feature that I want to have incorporated, is the ability to stand this trailer up on it's tail for storage.
It's going to need some semi-circle protection bars at the rear corners that extend past any other portions of the tail end, except maybe the bumper, and actually, they could/should probably be attached to the bumper...
I'm thinking that I could rig up a winching system to pull on the tongue to raise it to a vertical position and sit on it's "butt" if I have a long section of time that I won't be using it.

I was planning this for my build as well. I was going to make a "stand" that will slide into the receiver on the trailer's rear bumper when I wanted to store it upright.

I know a receiver is mighty handy.

Good luck,
Billy

 

[The Adam Blaster]

Ok, I'll solidify the needs of the hatch now - 24"W x 26"H.
That's at least 2-3 extra inches larger than either a 60 or 80 L fridge, so that should be enough space around for a shelf below the fridge, and some extra width for the slides as well. I'll have to edit my first post now...

I'd like to get some slides that would fit underneath, I am just not sure on the load capacity - especially if I end up getting a large 80L model fridge. That will be a future product anyways, so I can do the math on the load capacity of the loaded fridge at that time. I know the 80L models tend to weigh around 70-75 pounds empty, I actually have no idea how heavy a fully loaded 80L fridge would be, probably a lot...

As for the placement of the axle, I'm thinking dead centre at this stage.
In camping trim, I'll have two 31" or 33" tires right in front of the main box, in front of those I'll have a larg-ish nose box that will eventually have at least one large and heavy battery in it, possibly 2. So there will be lots of weight out front, and the only counter-balance to that will be 2 jerry cans that I will mount on the platforms that are just behind the wheel wells. But the net result is that the front will be heavier than the rear.

Before I have that all set up, and for it's maiden trip from Windsor to AB loaded with my tools etc., I will make sure to load the front of the trailer with the heaviest items. As well, I just remembered I have one of those really large (4' long) Rubbermaid Action Packers that I can fill with stuff and bolt it to the tongue to help load the front up even more. So, with those provisions, I should be pretty good.

 

[The Adam Blaster]

I was in the "Cheap Fridge" thread, and a vendor posted up that he's making slides for the Edgestar/Whynter line of fridges, probably the brand that I will eventually buy.
A perfect slide with cutting board attachment:
http://tembotusk.flyingcart.com/index.php?p=detail&pid=4&cat_id=

And it will easily fit in my 24x26 hatch.