Questions about doing an FJ40 SOA with 80 axles (1 Viewer)

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pjohnson

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BTW, don't use the shackle reversal kit you have with a SOA. The proper method is to have your front spring mount as flush to the frame as possible and the shackle mount through the frame (although flush as @batcon shows isn't bad). This keeps the spring geometry as close to horizontal as possible and keeps the overall SOA height as low as possible.

I have this exact design on my 40 with flat stock springs and 37x12.5 tires. No problems.
 

DangerNoodle

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BTW, don't use the shackle reversal kit you have with a SOA. The proper method is to have your front spring mount as flush to the frame as possible and the shackle mount through the frame (although flush as @batcon shows isn't bad). This keeps the spring geometry as close to horizontal as possible and keeps the overall SOA height as low as possible.

I have this exact design on my 40 with flat stock springs and 37x12.5 tires. No problems.

Could I get some pictures of that for reference? I don't really have much to base what good and bad looks like on these. How is clearance with the 37s? Do you have much rubbing or need to trim any panels with them?
 

pjohnson

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I was afraid you would ask for pics. I don't have my 40 with me right now. I'll see if I can dig up anything.

The only thing I had to do was turn the steering stops out to prevent the tire from rubbing on the spring. I don't mind this because it also helps prevent birfield breakage due to greater stress (bigger tire) and extreme angle of the joint. At full stuff with the wheel turned, I get a slight rub inside the fender. Enough to leave a small tire mark.
 

DangerNoodle

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I was afraid you would ask for pics. I don't have my 40 with me right now. I'll see if I can dig up anything.

The only thing I had to do was turn the steering stops out to prevent the tire from rubbing on the spring. I don't mind this because it also helps prevent birfield breakage due to greater stress (bigger tire) and extreme angle of the joint. At full stuff with the wheel turned, I get a slight rub inside the fender. Enough to leave a small tire mark.

It was worth a shot. Thanks for the information though, that is really helpful!
 
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What wheelbase are you shooting for? You will have a lot of scrub with the 80 axles unless you stretch it a bit. I run a 60 axle widened in the front so I can turn 40's lock to lock and not touch the springs with the stops all the way in. It matches up pretty close with the 80 rear as far a width goes. You are talking about a 93-97 80 series axles (full float rear) I would assume? Do you have the axles yet?
 

DangerNoodle

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What wheelbase are you shooting for? You will have a lot of scrub with the 80 axles unless you stretch it a bit. I run a 60 axle widened in the front so I can turn 40's lock to lock and not touch the springs with the stops all the way in. It matches up pretty close with the 80 rear as far a width goes. You are talking about a 93-97 80 series axles (full float rear) I would assume? Do you have the axles yet?
I'm picking up the axles this weekend. It is a full float rear, but it has the reverse cut high pinion on the front (which I am a bit worried about), but I am planning on gearing both to 4.88, doing a complete rebuild and installing ARB lockers. Hopefully, the 350 and stock transfer case will not have enough power to break that stuff super easily. I'm not super keen on trying to find a 60 axle and space it to fit, but I think I can try and adjust the steering or fabricoble a stop together to try and stop stuff from rubbing. I really like the stance of the 80 axles, and that is what I'm going to shoot for.
 
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I have run 38.5" and 37" tires with 4" lift SUA. Simple, stable and reliable. Beadlocks, lockers and low tire pressure will do more for crawling than the SOA.
 
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No matter what you do, something ends up being the weak link. For the high pinion 8 inch differential on the front axle of an 80, it is going to be the pinion gear, especially with 4.88 or 5.29 gears. Even so, people wheel 80s pretty hard and they weigh more than 40s. Carrying a spare differential is a little unwieldy, so if you go with an 80 front, you might think about running weaker hubs, like Warns, that are easier to replace.
 

RustyNailJustin

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As stated it's not a big deal these days. I would build a hybrid like @reddingcruiser did. Get the big knuckles and CVs with a 9.5 center section and Hellfire knuckles all at the width you want. Super straight forward, easy. Just be ready to drop 5K on a steering axle. This frontend we did is on a 4600 class Toyota truck but same concept for whatever.
IMG_20191107_185017.jpg
 

mattcamp

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Thanks for the picture. That helps to clear stuff up a lot!
As stated it's not a big deal these days. I would build a hybrid like @reddingcruiser did. Get the big knuckles and CVs with a 9.5 center section and Hellfire knuckles all at the width you want. Super straight forward, easy. Just be ready to drop 5K on a steering axle. This frontend we did is on a 4600 class Toyota truck but same concept for whatever. View attachment 2127844
I love seeing paint on tightened nuts and bolts and I keep telling myself to do that and I never do... I know its unrelated to the whole soa/sua conversation, oh yeah, this might be, I ran 36" swampers sua w/4" springs but my 37" iroks are the same hieght as my 36" swampers so take that for what it's worth, probably not all that much. Cheers!
 

DangerNoodle

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mattcamp said:
I love seeing paint on tightened nuts and bolts and I keep telling myself to do that and I never do... I know its unrelated to the whole soa/sua conversation, oh yeah, this might be, I ran 36" swampers sua w/4" springs but my 37" iroks are the same height as my 36" swampers so take that for what it's worth, probably not all that much. Cheers!

Did you have to trim the rear panels to get those tires to not rub? I know that I'll have to check once everything is on this rig, but I'm deciding if I should start designing some rear fenders or not.
 

fjgoober

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I did it 5 or so years ago. I have been very happy with the the wider stance E-lockers are nice too!!! I've run 37.5's.

I went coil on the front and leafs on the rear. @Pin_Head is right, anything you do means changing the weak link.

I also put in an Orion, One thing you will want is a traction bar, even with leaf springs on a SOA you tend to snap rear pinion shafts if too much skinny petal.

I also moved the front axle forward I think like 11 inches??? to get a longer wheel base. My DD.

Here's the link:

 

DangerNoodle

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I did it 5 or so years ago. I have been very happy with the the wider stance E-lockers are nice too!!! I've run 37.5's.

I went coil on the front and leafs on the rear. @Pin_Head is right, anything you do means changing the weak link.

I also put in an Orion, One thing you will want is a traction bar, even with leaf springs on a SOA you tend to snap rear pinion shafts if too much skinny petal.

I also moved the front axle forward I think like 11 inches??? to get a longer wheel base. My DD.

Here's the link:


Sorry for the late reply, I just started looking at doing coils on the front. When you did it, did you 3 link the axle, if so, how hard was it to 3 link? Did you use stock FJ80 coil baskets? I'd really like to run coils on the front, but I need to figure out exactly how hard it would be to do.
 

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