Looking for SOA geometry experience input (1 Viewer)

Cdaniel

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Into a next phase of a rework project, Project link While waiting for some perches to arrive, I've started mocking up my SOA to see where things may or may not line up. I've removed the front hangers from the previous shackle reversal and am considering keeping the rear ones in place. With some stock springs attached under the axle and the original brackets in place, I've got about 42-3/8 between the spring eyes. The brackets hang off the front edge about 1-1/2. Shackle angle seems good. Anyone see any problem with building out the frame to support the original bracket in this location?

And what is the reasoning for moving the shackle mount into the frame rail I've seen on some SOA shackle reversals?

(Yes, I know brackets are on the wrong sides, easier to deal with right now)
DSCF0133.JPG
 
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I'm sure there is no problem, but it isn't optimal. I put my shackles in frame to lower the cog and to keep the spring flat in relation to the truck. Made setting up the cnt much easier.

Dan
 
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I'm sure there is no problem, but it isn't optimal. I put my shackles in frame to lower the cog and to keep the spring flat in relation to the truck. Made setting up the cnt much easier.
Using a hanger below the frame and a steep shackle angle will result in better flex due to the shackle angle. Putting the top of the shackle through the frame results in a more-vertical shackle with limited fore/aft travel. I don't see any benefit. It would be way harder to relocate if you f'd up the measurement too.

shackleReversal74.jpg

Before finish-welding. Hangers relocated from their original positions in the front. Profitt's outboard shackles to accommodate fj60-width axle:



The drop brackets you removed were there to keep the spring flat. The C&T might be easier that way, and if it's already done and you're working to that, it might be necessary, but if you have the luxury of doing the shackle reversal first and the C&T 2nd, do it. You have a lot more options. The high-steer clearance needs to be addressed at the same time. Trust me.
shackleReversal74.jpg
 
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What I found when I recently did mine was when you do the SR it changes the angle of the spring (obviously). So if the FRONT of the springs are higher in elevation, the hysteer arms wont clear the drag ling OVER the springs.
THREE ways to combat this if you leave the shackle hanger where it is as...

1. Rotate the caster angle up (TOO high and you get sluggish steering and pre mature wear on your steer components)

2. Raise the height of the steering arms (4x4labs can do this, but its spendy for his arms)

3. DROP the front hanger DOWN in elevation. Fast eddy did this IIRC.

I ended up cutting the rear shackle hanger so its about flush to the frame bottom. Have about an inch of clearance for the tie drag link over the springs, but....I may end up going with the 4x4 labs arms and having him bend em up a bit. I Set the castor angle @ 5* which (arguably) is almost the MAX you wanna go, depending who you talk to.

Ya just dont hear much about this when reading SR threads with SOA's, so I was surprised to find this out. It took a LOT OF TIME getting it to where its at on mine. Hope its worth it.:doh:
 
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Using a hanger below the frame and a steep shackle angle will result in better flex due to the shackle angle. Putting the top of the shackle through the frame results in a more-vertical shackle with limited fore/aft travel. I don't see any benefit. It would be way harder to relocate if you f'd up the measurement too.

View attachment 512978

Before finish-welding. Hangers relocated from their original positions in the front. Profitt's outboard shackles to accommodate fj60-width axle:



The drop brackets you removed were there to keep the spring flat. The C&T might be easier that way, and if it's already done and you're working to that, it might be necessary, but if you have the luxury of doing the shackle reversal first and the C&T 2nd, do it. You have a lot more options. The high-steer clearance needs to be addressed at the same time. Trust me.
Well, I am not concerned as much with ultimate "flex" as I am with strength and height. My front end flexes just fine and has for 8 years. My shackle mount is strong and everything lines up.

Difference of opinion I guess.

I also feel through the frame is much strong then welded to the bottom.

My shackle angle, I believe, has also kept me from going through springs like crazy.

Since were posting photos, I'll get some up later for an educated decision.

Dan
 

Lil'John

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Through the frame with a shackle or not has nothing to do with the shackle angle.

If a person picks a poor location, then yes, the shackle angle will suck.

One of the more popular places to put the shackle through the frame in an FJ40 is the rivet hole from the old spring hanger. This plus doing the "popular" 1" frame extension WILL result is a poor shackle angle.

On my last SOA conversion, I used a 1" block to space the spring from the frame. I then mocked up my shackle at ~45 degrees. I THEN drilled a hole through the frame and welded my sleeve in.

I am going to take the same approach on the rear of my FJ55.
 
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I just did what lil' john described, I put a 1.5" steel tube in-between the frame and spring, my shackles were more like 60 degrees with 6" shackles eye to eye.
 

Cdaniel

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Thanks to everyone chiming in so far. As I expected there's many approaches to this mod out there. My thinking right now is: If it's feasible to keep a reversed shackle configuration with my SOA while reusing the bracket currently welded to the frame, (as shown in the picture) I'll go that route. It would seem that it's been done this way in the past. Would love to see some more pictures/experiences with it.

If this approach is problematic, and removing that existing bracket is required. I'll be seriously looking at putting all of my original Toyota parts back on with the shackle in the front. The theory behind reversing the shackles makes some sense, but I've never really seen a major difference in my real world wheeling experiences. Not worth the extra work if that bracket needs to come off. And even less work If I leave it there.

However I do like the improved approach angle with the SR-SOA

I know this statement may be controversial, but.....

I'm sticking with OEM shackles. I'm not really a fan of extra long shackles these days. I've had them and observed them over many years. I see lots of extra cantilever loading on the bushings, quirky handling on and off road. To me the perceived extra suspension flex is overrated. Better to find some longer springs if that’s what your shooting for. IMHO when locked front and rear, the tires on the ground thing isn't as important anyway. Traction is where the weight is. A lightly loaded tire touching the ground adds a little, but the less flexy suspended one will get there soon enough. With good gearing and throttle control I can carry that airborne tire to a more useful purchase everytime.

Not to take away from those uber flexy rigs out there. If it works for ya, Wheel on! I'm happy to watch if it takes you farther than I can manage. :cheers:
 
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Here is mine, late but what the hell.

My shackle angle appears horrid but works well for me.

The front setup is all tied together, Steering box mount, SR, etc. I can get you better pics if you so desire.

Dan
shackle reversal 1.jpg
shackle reversal 2.jpg
 
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To add, I am in complete agreement about articulation, it is overrated. The down tire is barely making contact anyways and really plays no part when locked up.

My front setup is AT LEAST 7 or 8 years old, no cracks, no fatigue, same springs.

Dan
 
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Here is mine, late but what the hell.

My shackle angle appears horrid but works well for me.

The front setup is all tied together, Steering box mount, SR, etc. I can get you better pics if you so desire.
That shackle angle will, of course, work fine. It will make for a harder front suspension given the same springs. Some people like that. My suspension rides like a Cadillac and I have almost 8" of usable down-travel for the whole axle, both sides at the same time. Jack up your rig from the center of the front bumper and see how far up you can go with the wheels on the ground.

Where's your steering? At the rear of the axle?
 
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That shackle angle will, of course, work fine. It will make for a harder front suspension given the same springs. Some people like that. My suspension rides like a Cadillac and I have almost 8" of usable down-travel for the whole axle, both sides at the same time. Jack up your rig from the center of the front bumper and see how far up you can go with the wheels on the ground.

Where's your steering? At the rear of the axle?
It works fine, steering is 4x4 labs.

I'm not saying your setup is inferior in anyway, I'm just saying that mine has worked for nearly a decade as is.
 

Cdaniel

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Been hunting around for steel to do an extension.

Where in the heck did they find tube or channel that's 3-1/2" tall?
----and 2" wide?:hmm:



 

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