trailer build.....leaf placement

[hidefxj]

Hey guys, I am building my first expedition trailer and I have my first question.
Basically, I am modifying a 4x6 trailer. I have a rear axle and leaf spring setup as well as mounting plates from a mini van. I want to utilize a SOA set up.
Most people flip the trailer upside down and put their axle on top for assembly purposes then right side the rig when done. Does this create issues with the leaf springs?
Every time I have replaced leafs on a vehicle, they seem to have tension on them which tells me the perches are installed slightly inboard (closer together) and the leafs installed with a "forced bow" .
Is there some formula or rule of thumb when placing the perches on so there is an adequate amount of tension or "spring" from the very beginning?

Hope I explained this well enough.
Thanks in advance!

 

[goodtimes]

There shouldn't be any tension or pressure on a leaf spring when it's installed & you haven't loaded it - there is no 'built in' or 'forced bow' to them (other than the arch).

When I built my trailer, I welded the spring hangers to the frame while it was upside down, but flipped it right side up before I welded the perches to the axle. This let me put the fenders, tires, & wheels on it to double check the axle position before I welded the spring perches on. I don't see an advantage to doing all of that while it is upside down.

 

[hidefxj]

Thanks good times!
So just to be clear, when I weld the perches in place, they should allow the shackles to hang straight down when the rear is on the ground or off the ground?

 

[Mark Harley]

Many ideas on shackle angle out there.
My knowledge is that it has full motion, the eye does not hit the frame on full compression and is not pre loaded.

http://gitout.com/content.php?179-Leaf-Spring-Tech-Shackle-Length-Shackle-Angle

 

[hidefxj]

Mark,
Yes, this is essentially what I was looking for. I just didn't know how to ask for it.
I'm installing from scratch, the axle and wanted to get the shackle mounts correct from the get go.

 

[Mark Harley]

Keep us posted on the build.

 

[hidefxj]

Oh, I will definitely keep you guys posted. I am in the gathering stage as far as the foundation is concerned. Once I get a little more free time and warmer weather I will immerse myself in the build and not come up for air food or sleep until completed.