HF trailer frame + subaru IRS

[alfio]

hello all, how's everyone doing?

i'm reaching out for some help with my trailer project. i picked up a bolt-together trailer from Harbor

Freight (i know, i know...) and i'm wanting to strengthen the frame and, while i'm at it, also modifying the

design to better suit my needs.

this is what the underside of the frame looks like:

any tips on strengthening the layout? i found this on another forum:

i will probably (at least) do that much to mine to give it a little more strength but is there something else

i can do to complement?

also, like i said above, i'm modifying the trailer in two ways. 1) i'm going to add a central draw tube

running all the way down the trailer (which shouldn't be too complicated) and 2) i'm swapping the leaf

suspension to a torsion bar (IRS) setup i got from an old subaru to copy deepmud's trailer:

i picked up the same torsion bar set up but haven't started fabbing up mounts for my trailer frame. any ideas

as to what the best way to do it would be? my frame is slightly wider than the mounting points

for the suspension (by about 6") so i will have to supplement the frame somehow to create a solid mounting

point.

this is the what the subie suspension looks like:

i don't have a MIG but i'm decent with an ARC welder.


to sum up, i'm looking for input/ideas with 1) strengthening the frame and 2) adapting the subie suspension/fabbing mounting points for it.

i would appreciate any ideas with this, thanks!

 

[deepmud]

Ok - I am, of course, a big fan of the Suby suspension. Lots of travel, sturdy, has shock mounts, easy to get parts, mine is heading towards 20 years of HARD use and I STILL haven't swapped out those old bearings, so they are like 32 years.

Harbor Freight trailer - not so much in love with it. I don't want to be all negative, especially since this isn't "should I get an HF trailer" - this is " I bought it already"......

So....you plan to mount an extendable 2" tongue.... I think I can see a way to do that, and build it as a subframe for the suby axle to mount to, that will bridge to the extra width of the HF frame. I'm not sure you'll have a lot of value from the HF frame at that point, but I'll try to do a bit of "paint cad" to show my thoughts on how this might work.

Did you see where I converted mine to extendable tongue? I've lost track of which thread I posted that work on....

 

[Aspen Trails Trailers]

If the frame is 6 inches wider than that attachment points on the Suby, aren't you going to run into trouble with tires hitting the frame? I maybe missing something.

Bob

 

[Mark Harley]

Cut 6" out of the center of the Subie sub frame.
slide in a sleeve, square it up and weld it together.

 

[alfio]

Harbor Freight trailer - not so much in love with it. I don't want to be all negative, especially since this isn't "should I get an HF trailer" - this is " I bought it already"......

right, i'm not an HF fan either but i got a good deal on this and i don't need much cargo capacity so for the time being, this will work. i also got the side walls kit for dirt cheap which will help make it more multifunctional. HF is horrible but for the money and my very limited needs, it should work out nicely

So....you plan to mount an extendable 2" tongue.... I think I can see a way to do that, and build it as a subframe for the suby axle to mount to, that will bridge to the extra width of the HF frame. I'm not sure you'll have a lot of value from the HF frame at that point, but I'll try to do a bit of "paint cad" to show my thoughts on how this might work.

yeah, that's the tricky bit, would love to see what you come up with since you are so familiar with this setup

Did you see where I converted mine to extendable tongue? I've lost track of which thread I posted that work on....

yes, i'm planning to do somehting similar with this one to get the same kind of set up going on

 

[alfio]

If the frame is 6 inches wider than that attachment points on the Suby, aren't you going to run into trouble with tires hitting the frame? I maybe missing something.

Bob

possbily, but i'm not there yet. once i figure out how exactly i'm going to try to mount the subie axle, then i'll worry about wheel clearances and such. but, yes, potentially that's another fun hurdle to deal with. if i figure it out tho, the trailer should end with the same track width and height as my truck which is the ultimate goal to all this

 

[Aspen Trails Trailers]

I think it needs to be six inches wider. Not sure how much of the stuff on the axle is necessary or used.

 

[deepmud]

So I'm imagining a piece of expensive 2" ID tube down the middle - your 2" OD tube fits inside, and can run to the back of the trailer or be pulled most of the way out - I think 20" or so of overlap would be enough - the HF frame is supported by the two 2" OD tubes (this is all square) that the Suby axle bolts to.

This subframe would be usable even if you decide the HF frame sucks and has to be scrapped - but I think it will work ok.

 

[deepmud]

That's a side view and sort of mini top view . The black tube part would be towable by itself. Does the terrible drawing make sense ?

 

[alfio]

That's a side view and sort of mini top view . The black tube part would be towable by itself. Does the terrible drawing make sense ?

yes, makes perfect sense. as soon as i source enough steel, i will give it a go. thanks man, much obliged

 

[navigator]

I think I would go with Mark's suggestion and cut out the center, extend/sleeve it.
I like deepmud's suggestion also but it would seem if you go through that much trouble, it wouldn't be much more trouble/expense to build a whole new frame.
You could likely throw a sheet of plywood on the HF trailer, sell it on CL and get more than enough money to fund building the trailer like you want.

 

[Lizella Fella]

Subaru Suspension

What year and model suspension are you using for this project?

 

[deepmud]

I think I would go with Mark's suggestion and cut out the center, extend/sleeve it.
I like deepmud's suggestion also but it would seem if you go through that much trouble, it wouldn't be much more trouble/expense to build a whole new frame.
You could likely throw a sheet of plywood on the HF trailer, sell it on CL and get more than enough money to fund building the trailer like you want.

There is a steel torsion bar thru the center of the axle - you can't cut it and still have it function - it's not like the rubber-sprung trailer axles. He's also using a 4wd axle vs a 2wd axle - this means not using a traditional spindle/cone bearing arrangement for the wheel bearings, more of front wheel drive, caged-bearing-assembly type. The bearings are beefy, and placed about 2" apart this is as opposed to many modern bearing assemblies that are spaced very closely and will not tolerate much wheel offset. A plus of the 4wd axle has preload adjustment - I'd build the trailer with the preload set to minimum, and then crank it up if it becomes clear it needs more load capacity. On my old Suby that I treated as a "side by side ATV" (oversize tires and chains will get you waayyy out there) I got about 2" more clearance in back by cranking the preload to max.

I think is correct that the HF trailer, if sold, would pay for the steel you need for the whole trailer - only the value in the HF frame might be that stake pockets that will allow you to put sides on with ease - but I am sure you can just buy stake pockets and weld them on your own frame. Even if you got the HF free, I still think you would like your own steel better than stripping the HF trailer down for a simple rectangle of metal. The heavy duty subframe idea would still make sense. The frame on top could be 2"x2" with 1/8" wall and be plenty strong, what with the over-built tongue/suspension assembly.


EDIT: on the width of the Suby axle - the mount points are well inboard of the wheels - perhaps Alfie can lay the Suby axle on top of the HF frame so we can see, but it may be that it's just fine as-is. If he want's it the same track width of the tow vehicle, he may need some spacers - I've never found it to be an issue, however. I've towed my trailer with everything from a 3-wheeler to an Expedition, sometimes in VERY nasty terrain - I don't think it's important to track in the wheels of the tow rig, "usually" - ymmv

EDIT 2: - my thread, for anyone not familiar : http://www.expeditionportal.com/forum/threads/19803-homebuilt-Subaru-IRS-trailer

 

[deepmud]

I know this is old - but did this ever get built?