I'm finally making headway on this project, and have cut the angle and box iron for the perimeter of the trailer. The bed will be 46" x 72", with a 42" length tongue. (Yes, I would have preferred to go with a 48" width, but that won't fit between the tires without modifying things)

 

Here's my dilema... Where do I locate the "axle" assembly on the 72" (6') front-to-back length? I can locate it anywhere, as I'm not using any of the Brat sheet metal. The weight will be carried just like the stock Brat setup utilizing the 4 mounting locations (two on each side), front and rear of the torsion bar. Note that I'll need spacers here of different thickness to level things out, and overall, to provide clearance over the torsion bar/swing arm junction flange.

 

Since the wheels trail behind the mounting location by 15", I'm thinking of making the mounting location dead center on the 6' run of the bed, which would locate the wheel center at the point 7/10's of the way through the bed length.

 

Anyone have any thoughts on the topic?

The rule of thumb on trailers (that I know of) is to shoot for a 10% tongue weight when fully loaded. If you could get the (estimated) weights of everything you could determine where the axle should go to match the "rule."

 

Just an idea...

The rule of thumb on trailers (that I know of) is to shoot for a 10% tongue weight when fully loaded. If you could get the (estimated) weights of everything you could determine where the axle should go to match the "rule."

 

Just an idea...

 

Thanks, that's more than what I had to go on other than looking at other trailers to see where they located the wheels. Typically, that seems to be about 60/40, strictly from a length of bed standpoint.

 

I'm just struggling a bit with how the trailing arm suspension factors in. Is the pivot point considering the mounting location or the wheel location? The wheel is what I'm thinking.

Its gonna be the wheels, as the trailer's center of gravity will be directly over them.

Be careful putting the CG directly above the wheels... any weight in the back will give you a negative tongue weight. Not very good for towing, and really bad when it's time to unhook the trailer. That would be one helluvan uppercut!

 

And yes, the wheels are the pivot point. The trailing arm just moves the CG forward a bit.

 

Lemme know how it goes!

Thanks for the input - it's kept the brain cells firing. No question, I'll keep a front weight-bias with this setup, but I think I'm going to move the mount location forward 8", now that we've confirmed that the WHEELS are the pivot point, not the mounting location. That will locate the wheels at a 60/40 split (towards the rear) on the bed, still keeping a forward weight basis.

Take a look at this thread:

 

http://www.ultimatesubaru.org/forum/showthread.php?t=41383

The offer for the spreadsheet is good for you too. Let me know if you want it, and how to get it to you.

Hey, there's two of us with this nutty idea!Appreciate anything that will help me to do this right (or at least "better"). Feel free to send anything along to brad.anesi AT netiq.com

 

Thanks!

I didn't want to disappoint Mr. Moose, so here's a pic of the basic layout.

Time for an update with pics. A couple comments - looking for any thoughts, suggestions, etc...

 

1) Unloaded as it is, there's obvious positive camber in the wheels (I'm going to guess about 2-3 degrees. Do we think this

will move closer to neutral or somewhat negative with a load on the trailer?

 

2) Will the way I've got the rear assembly mounted to the frame effect the change in camber at all? The geometry is somewhat

different than when attached to the Brat body - the attachment point sits higher. As a result, I need to space the forward

mounting points down about 1.5" compared to the rear. On the stock setup, the two vary in height by only about 1/2".

 

3) Can someone help me out with the operation of the center adjustment bolt? I assume this stiffens/loosens the

spring mechanism, which might be helpful depending on the weight of the load. Unloaded, I think I'd want it full

soft, right? Is that fully counter-clockwise?

 

Okay, enough talk....