Spring Over Axle on the FJ (SOA) (1 Viewer)

[Ianominous]

I have read a lot on here about the Spring Over Axle.

The majority list it as one of the top 5 mods for the FJ.

I also know people that have done many and say that it made it ride worse and they switched back.

My question to the crew is... why do you all love SOA? Is it just the chassis height?
Obviously the diff will be the same height etc..

I am about to start my project and keen to hear the reasons for and against.

Cheers n advance

 

[snaggletto]

Main benefit is leaf flexibility. The axle has more leverage to twist and droop and compress the springs. Also you get 5-6" of lift (35-38 in tires) with flatter stock arch springs. Finally the perch and leafs are not mounted under the axle so better clearance in those areas. There are more than a few problems that arise also. Body roll, axle wrap, drive shaft angles, steering components, cut and turn knuckles etc. Done well can be great, done poorly a nightmare..,

 

[Ianominous]

That must be the difference. How well the work is done and all of the other adjustments required. Cheers

 

[franklin40]

with larger lift you can get larger tires so the diff height isn’t actually the same off the ground. bigger tires makes more axle clearance.

 

[workingdog]

For the same tire, the diff, engine, transmission move up about 4", meaning you are dragging steel over a lot less rocks.

 

[reddingcruiser]

Also, better approach and departure angles. Add a shackle reversal up front and get a little more. More clearance around the corners and along the rocker panels/sliders. I have no regrets about doing mine.

Downside? if your wife is short you'll never hear the end of it!!!!

 

[Ianominous]

Also, better approach and departure angles. Add a shackle reversal up front and get a little more. More clearance around the corners and along the rocker panels/sliders. I have no regrets about doing mine.

Downside? if your wife is short you'll never hear the end of it!!!!

Getting Separated at the moment so wont have to worry about it!

 

[reddingcruiser]

Getting Separated at the moment so wont have to worry about it!

Been there, done that! I have a 'keeper' now, so putting the sliders slightly lower than I would have normally so she can get in was worth it. She still expects me to stop near a rock on the passenger side, though. Which I always do!

 

[Toyota Pilot]

As stated before the difference is in doing it right. When I bought my 40, the SOA was horribly done, and it wandered all over the road at higher speeds. After a cut-n-turn, and 4x4 labs high steer kit, there is a night & day difference... I love it now.

 

[White Stripe]

I went soa in the rear and sua in the front. It handles great and is pretty stable, but the front is stiffer than stock springs. I should have went with Deaver springs rather than alcan up front. I think Deaver knows how to make a nicer riding spring compared to alcan and it would ride nicer. I did not have to go hi steer which saved me some money but had to buy custom springs which cost me some money. You can keep a soa suspension very low if you use reverse eye springs though. As in probably only 4" of lift. In which case you wouldn't have to cut n turn the axle.

 

[Tank5]

You can keep a soa suspension very low if you use reverse eye springs though. As in probably only 4" of lift. In which case you wouldn't have to cut n turn the axle.

White Stripe, this sounds appealing to me. Do you know of anyone who built a soa with reverse eye springs. I would like to see how it looks. It would be ideal if it doesn't require a cut and turn or steering modifications.

 

[White Stripe]

White Stripe, this sounds appealing to me. Do you know of anyone who built a soa with reverse eye springs. I would like to see how it looks. It would be ideal if it doesn't require a cut and turn or steering modifications.

No not for sure. I first heard of the idea through Dave at 4plus. But not sure if he did it. You could have a spring shop just make you stock main leafs but with reverse eyes and then add on the other leafs from old stock leaf packs to make a complete leaf pack. I would think you would still have to likely go high steer to clear the leafs most likely. Cut n turn is not necessary either way, just install high angle ujoints driveshafts from newer toyota 4x4s and you get 45 degrees of ujoint flex vs the stock 25ish degrees the stock cruiser ujoints have. But a cut n turn is nice if you want more than the stock 1 degree of caster. Reverse eye leaf springs would lower the ride height over a normal soa probably around 1.5" maybe 2". Basically giving you a 4.5" lift over stock I would think. You would also still want a traction bar most likely in the rear. Here are some examples of different spring eyes and you can kind of see how it works...
Total Control Products

 

[SMG]

White Stripe, this sounds appealing to me. Do you know of anyone who built a soa with reverse eye springs. I would like to see how it looks. It would be ideal if it doesn't require a cut and turn or steering modifications.

Or through the frame.

 

[jim land]

i remember an article in toyota trail mag about reverse spring eyes low soa .
also you can look at rubicon express soa springs for yj , they have the reverse eyes

 

[Tank5]

I don't want to hijack the original posters thread so I will try to contribute to his questions and then ask some questions that I hope may be helpful too. I have never owned a SOA rig so you know but I have been on an off interested in doing a SOA on a 45 project I am planning.

My Pros

• I have been considering it because I want to add some lift to my project
• I like the clearance you get from moving the springs over the axles
• Undercarriage looks cleaner to me with SOA
• Possibly a cheap way to lift it if I do my own fab work (SUA lift kit is about $2200 for 2.5inch)
• Good if I don't have to alter the steering
• New to me reverse curl leaf spring eye lowers the SOA lift

My Cons

• I only want 2.5 to 3 inches of lift to run 33" tires, this may be to much lift for that
• I really don't want the tire size to look disproportionate to the lift and I really want to stay with 33s
• Expect I would have to alter the steering for hi-steer
• Have additional fab work required
• Higher center of gravity compared to a SUA lift

I am still on the fence at this point but would like to know if anyone has seen a 40 series SOA with the reverse curl eye leaf spring. Looking at the links provided by @jim land it says it dropped the height about 1.5 inches. So if a normal SOA giver you about 5-6 inches of lift this could get it down to 3.5 to 4.5 inches. I think the lower side of this maybe ok with 33s. Although the the rear spring pack on a 45 is pretty thick compared to a 40 spring pack.

Asking those that have done this do you think a SOA that resulted in 3.5 to 4 inches of lift would need a high steer set up?
If anyone has picture of a 40 lifted with reverse eye springs please share.
I am not interested in altering the 45 frame with a shackle reversal or running the shackle through the frame so the SOA would use the original spring hangers.
Please share any known tricks for doing a SOA that will help keep it low.

​

 

[Tank5]

Please share any known tricks for doing a SOA that will help keep it low

Ever since Whitestrip mentioned the idea of reversing the eyes on the main spring to lower an soa lift I could not stop thinking that it could get me closer to where I want to be, so I did some research.

I contacted a local spring shop and inquired about having custom main springs made with a reverse eye and they suggested just reverse arching the stock spring would be a lot cheaper. Probably around 200.00 to have this done. I am pretty set on giving it a try just as an experiment at least and see how it works out. This project is not even started, so I am hoping that by sharing someone else may try it first and let us know how it works.

 

[S4Cruiser]

Ever since Whitestrip mentioned the idea of reversing the eyes on the main spring to lower an soa lift I could not stop thinking that it could get me closer to where I want to be, so I did some research.

I contacted a local spring shop and inquired about having custom main springs made with a reverse eye and they suggested just reverse arching the stock spring would be a lot cheaper. Probably around 200.00 to have this done. I am pretty set on giving it a try just as an experiment at least and see how it works out. This project is not even started, so I am hoping that by sharing someone else may try it first and let us know how it works.

In for following along!

 

[White Stripe]

Reverse arching the old stock main leafs? That sounds like a recipe for spring breakage to me. Do they realize how much the leafs will be flexing on a soa cruiser? Maybe I am misunderstanding though.

 

[Tank5]

Reverse arching the old stock main leafs? That sounds like a recipe for spring breakage to me. Do they realize how much the leafs will be flexing on a soa cruiser? Maybe I am misunderstanding though.

That is what they are suggesting. I did not disclose that I would use them for soa set up. I figured I would do that when they saw the springs in person to determine if they still recomend going this rout.

 

[69LC]

My understanding about leaves is that once they’ve been built and used they have a memory.

To re-arch them backwards to use them upside-down would cause me to think they would fatigue much faster and not hold their arch.

If you want to use the flipped spring eye idea have new main and military wrap second leaves made for the purpose and arch.