Spring Over Axle vs Spring Under Axle

[Fordguy77]

I've been doing a lot of thinking on this. And i am 95% certain that i would like to run a spring over set up on the 60. The main reason i am thinking about this is because of cost. For a SOA(around a 6inch lift and will clear 35's with minimum to no trimming on stock springs) kit i am looking around $450 to $700, while a 4in spring under kit is running around $1345. The biggest concern i have seen with the SOA is the steering issues it causes. Which i have found a few different companies making solutions for this issue between $200 to $500. Which puts me between $650 to $1200. I have read that 60's with SOA on stock springs flex awesome and way better than the Spring Under set ups, however axle warp becomes more of a problem/concern with the SOA. Both setups will require the use of extended brake lines and different drive-shafts so it is a wash there. I like the SOA becuase it requires the use of a hi steer application which i would like to do anyway, and still comes in cheaper than the kit. The nice thing about the lift kits though is that most include shocks, as here i would have to come up with my own(which is a pro and a con). What are some of your opinions regarding the differences between SOA vs SUA and which would you run if it was you?

[1freaky1]

Use the springs you have now(unless worn out) and just put the axles under the springs for 4-5 inches of lift then invest the money in drive shafts, decent shocks and hi steering this should save you $$$. And from experience there is less axle wrap on this setup than SOA with the same springs. Due to the way the axles pull and push on the springs.

[scout man]

I would go SOA. I did that in my scout and I am really really happy that I went that route. I get a ton of flex from me stock springs this way, and usually aftermarket lift springs just really dont like to flex. I drove a scout with a 4" lift after having done my SOA, and it definitely reaffirmed that I made the right choice. What comes in the "kit" for an SOA? I was able to do mine without any sort of kit, including turning the knuckles and stuff. I think you will find SOA can be completely done way cheaper than lift springs.

ALso, when it comes to shocks let me know, I probably have some for you for cheap.

[Haku]

I went both ways on different rigs. My current truck came with SOA and to really get the kind of performance out of these trucks with a spring under, you have to work a lot harder and it really takes some serious fabbing. Its probably a bit different on the Cruisers though. I know there is guy on Pirate 4x4 that is trying to do a longish travel spring under project, and he had to rebuild parts of his frame and do a couple other things that made for some rather involved and complex fabrication.

On my Samurai I wanted to keep it Spring Under for the same reasons you mentioned, so I went with a Missing Link kit and 2.5" lift springs. A friend had the same missing link setup, but went SOA on it with stock YJ springs, and I think his ride was a bit nicer offroad because of it, but I think I had just a tad bit more lift.

For what its worth, SOA is a huge bang for your buck and allows you to use easier to source stock parts and will allow for a bunch more uptravel then anything SUA will. Like you said, high steer is kind of inevitable no matter what, and will answer 90% of the problems you will get with steering. Just make sure that when you weld the spring perches on that everything is kosher with the caster and driveshaft angles and you won't have any steering or death wobble issues. A cut and turn on the axle might be worth doing, but not absolutely necessary I don't think.

If I was doing it to a rig now, I wouldn't hesitate to go SOA again.

[scout man]

oh, I also have some caster shims for sale if you need them....

[Fordguy77]

What comes in the "kit" for an SOA?
One of the kits i was looking at is the one from Ruff Stuff Specialties. Its $425
http://www.ruffstuffspecialties.com/catalog/images/Complete%20FJ40SOA%20kit.jpg
The other kit i was looking at has about half of this stuff but has a cut and turned axle for $500

[Haku]

Its not hard to do the cut and turn yourself. Just grind down the weld, and then use your precision millwright skills and do the angle checks and such a million times before you weld the sucker back up. You will only really need to do this if the ujoints of the driveshafts bind up due to bad angles and you have to turn the pinion upwards. Both of my axles are pretty much flat to the ground (as they are in stock configuration) and I haven't noticed any real issues. I'll probably turn the rear one up if I ever redo the spring perches, but thats no big deal since its not a steering axle. The front axle on my rig is quite a bit taller then it used to be, and I haven't really noticed it being an issue.

Oh, and I really like Ruffstuff. They have great kits, and seem like really good guys to work with. Haven't really heard anything bad about them, and plan on giving them some business in the nearish future for a 3 link kit. I drool over their fabricated axle housings too, and will so even more when they finally come out with the brand new upgraded knuckle balls.

[Fordguy77]

Oh, and I really like Ruffstuff. They have great kits, and seem like really good guys to work with.
Yeah, i've picked up a few things from them and have really liked what they have sent me, also they have always had great customer service. They just added a bunch of new stuff on there site this last month it looked like. I think this is the cut i am most likely to go with, and i will worry about the cut and turning after i have it all mocked up to see if there is going to be any binding.

[scout man]

If you have a standard u-joint driveshaft before the spring over, and you are switching to the CV joint then you do have to cut and turn, as these types of shafts operate on completely different principles when it comes to angles. Josh, yours was always a CV shaft, so you wouldnt have to change anything. Chris will most likely have to cut and turn. I definitely had to do it on mine. It simply would not have worked otherwise. And Josh is right Chris, a cut and turn is something that I would think you, of all people, would be perfectly capable of. With your mechanical and fabbing abilities I dont think you would have any difficulty with this.

That kit has a lot of crap in it!!! Might be worth purchasing just to get it all premade and all together. I ended up doing a lot of this myself. New u-bolt plates I made myself, bought new u-bolts seperate, made new spring perches, replaced my bushings at a later date, made my own shock mounts, etc. But if you have the money, then the kit would definitely save you a lot of time if not money!! Not sure I could even tell you what a few of the brackets in that kit are for though!!

[Rob]

... switching to the CV joint then you do have to cut and turn, as these types of shafts operate on completely different principles when it comes to angles. Chris will most likely have to cut and turn.

I have an SUA lift on the 40 and had some driveline wobble. Got a cut and turn and a driveshaft with a CV on the T-case end and the wobble's gone.

[Fordguy77]

The SOA kit they offer, also comes with the brackets for a disc brake conversion on the rear axle using what i believe to be uses a gm caliper(which i am not sure of) and a custom disc brake. I am not sure if its in the picture, but i do believe it said this kit can be ordered with a shackle reversal. So that might account for some of the brackets in there. I think it would be a nice time saver to just buy the kit.
Thanks for your vote of confidence in my mechanical and fabbing abilities. I really lack the sq feet to do this right now though :( which pretty much sucks! But i Believe this problem will be solved sometime soon. All this is Dependant on the ranger being back together soon(things are finally starting to come together on this).

[Mporter]

Both setups will require the use of extended brake lines and different drive-shafts so it is a wash there.

I got an OME kit for mine and I didn't need any new brake lines or driveshafts. Granted I still use my swaybars 100% of the time so that limits my flex a lot.

I'm going to be getting some extended lines and making some quick disco's here soon.

[Mporter]

And for what it's worth. Eventually i'm going to do SOA with 35's

[Brody]

HEy Chris

Call or Pm me, or email me. I have two very good articles dealing with the pros and cons of SOA and how to do one right. One article is an round table discussion with the who's who of Toyota guys. You are welcome to them and I will set them out for you when I get back to the house.

Me, I am all in favor of sacrificing a little (and I mean a little) ride quality on the road for a better performing off road rig, so there is no question in my mind.... I would do a SOA. The only other way that you are going to get the benefits of the ride quality of a stock configuration (ie-better road ride) and the lift is to spend a fortune on getting custom springs made. Going with the SOA eliminates most of the expense and there are many reasonably priced conversion kits around for it. Basically, you just need to make up your mind what you really want the rig to do. A SOA will give you a lot more options for off road. Give me a call. 303-507-3066

[Robert B]

i have no idea what you should do or anything like that and it is a chevy but my blazer has a SOA set up factory :)

[AccordRanger]

If i ever end up getting the Superlift kit for the Ex i was planning to SOA the rear to match.

[Fordguy77]

HEy Chris

Call or Pm me, or email me. I have two very good articles dealing with the pros and cons of SOA and how to do one right. One article is an round table discussion with the who's who of Toyota guys. You are welcome to them and I will set them out for you when I get back to the house.

Me, I am all in favor of sacrificing a little (and I mean a little) ride quality on the road for a better performing off road rig, so there is no question in my mind.... I would do a SOA. The only other way that you are going to get the benefits of the ride quality of a stock configuration (ie-better road ride) and the lift is to spend a fortune on getting custom springs made. Going with the SOA eliminates most of the expense and there are many reasonably priced conversion kits around for it. Basically, you just need to make up your mind what you really want the rig to do. A SOA will give you a lot more options for off road. Give me a call. 303-507-3066

Thanks Pete, i will let you know tomorrow.

[Brody]

The SOA kit they offer, also comes with the brackets for a disc brake conversion on the rear axle using what i believe to be uses a gm caliper(which i am not sure of) and a custom disc brake.

Should be the standard 6 lug Chevy half ton pick up rotors and calipers. They need to be milled out a little to fit over the Yota hubs. The 1/2 ton Chevy rotors are pretty much the standard that people use for disc brake conversions on a Yota. Keep in mind that if you do do this, you are also going to have to do some sort of T case E brake kit, too as you are going to lose the factory E brake. Many companies offer T case conversions: TG, All Pro, I think Marlin, probably a lot more. All work to some degree. Dave, at Davez Off Road Performance, is also working on an E brake T case conversion that is supposed to be the best of the bunch. You may want to give him a call to see where he is with that.

There are also quite a few other options for doing rear disc conversions on a Yota, too, so you may want to do a little more research before jumping into this part. I posted up a bunch of stuff and links in the Yota Make and Model section on this. Here is that link:

http://www.frontrange4x4.com/forums/showthread.php?8745-TOYOYA-INFORMATION-AND-LINKS/page2

My thoughts on that are the disc brakes on the rear would be nice, but only if you have the time and money for them. Otherwise they aren't what one would call a necessary item since 90% of your stopping power is from the front discs. Just keep the drums for right now and upgrade the pads, calling it good enough, much like I suggested to Sean after he spent $400 plus for a rear disc conversion.

SOAs will drive differently than the stock rig. Anytime you alter the height of any rig for any reason beyond stock, you are altering the Cg and they will both drive differently and have more of a tendency to flop if they aren't driven differently. You will gain off road performance.

4.56 gears will work for the 35s OK, but you are going to be at the low end of the power/torque curve. 4.88s will work best for 35s and will work with 37s, too, but again at the lower end of the curve.

Get a rear locker. Spend the money that you were thinking for a front locker on a T case upgrade so that you have the lower gears. With the lower gears and a rear locker, you will be able to do all the trails that you will want to do, with the exception of maybe the hardest remaining 10%...

[Haku]

Disc conversion isn't high on the list for me. I've looked into every different setup that Yota guys do, and they all seem like a PITA for not a huge amount of benefit. First and foremost is the lack of an ebrake/parking brake once you do it, so then you have to figure out how to deal with that. I've heard mixed reviews on the t-case ebrakes, with some loving them and others hating them. You can do a line lock, but they aren't technically legal as a parking brake since the pressure will drop over time. Chances are to get any benefit from the brakes, you will also have to upgrade your brake master cylinder, since the stock one may or may not push enough pressure to operate it. Not sure what the FJ's have in the back for a proportioning valve, but that will likely need to be upgraded too. So, in the end, I just decided to forgo the disc conversion and put my efforts elsewhere. My truck won't skid to a halt, but it certainly stops just fine.

+1 on the locker, even if its a cheap lunchbox style or even welded. My front locker hasn't been working (figured out that the power lead got pulled off the switch) and its majorly effected what I can get up.

Also, I wouldn't attribute a roll over directly to an SOA, but rather to the fact that the suspension is more supple and the COG is significantly higher. If you could get an equally flexy and tall SUA setup, then its not going to be much different.

Anyways, good luck fabbing and let me know if you need another set of hands or a welder or anything.

[Fordguy77]

I've heard mixed reviews on the t-case ebrakes, with some loving them and others hating them. You can do a line lock, but they aren't technically legal as a parking brake since the pressure will drop over time. Chances are to get any benefit from the brakes, you will also have to upgrade your brake master cylinder, since the stock one may or may not push enough pressure to operate it.
I've been doing some reading about upgrading my brakes all around, and i found some stuff on using second gen 4runners calipers and masters for the brake setup. As far as a t-case or transmission brake i am not to concerned about. I personally have never had any bade experiences with either or, and know a few people using them and they have never said a bad thing about them.


Anyways, good luck fabbing and let me know if you need another set of hands or a welder or anything.
Thanks for your offer! I'm actually going to be buying a new welder for this project! Well its for more than just this project but its giving me an extra reason to get it. I'm getting a new MIG, capable of running dual shield(makes welds look awesome!)! As well as a small TIG unit for when i build my exo(still planning on this though, good tig machines are expensive :frown: )

[Fordguy77]

4.56 gears will work for the 35s OK, but you are going to be at the low end of the power/torque curve. 4.88s will work best for 35s and will work with 37s, too, but again at the lower end of the curve.
I have been in a rather serious debate with myself about all of this. I really would like to keep from taking my gears super low, so thats why i have been leaning towards the 4.56s. However after doing more reading a lot of the SOA guys end up on 37's that started out with the 35's. So i would like to keep the option to go to 37's. I've started looking at the Marlin Toybox, and am thinking i might get the toybox and regear to 4.56's. I plan on swapping the 2f out for a Ford 351 Windsor which i am going to build to suit the needs of off road, so it should be able to cope with 37's with 4.56s for highway driving. That said the FJ will only be driven to and from trails after the SOA, as it has become the new Trail Rig. Do you think that the Crawl Box and 4.56s would be enough for 37s? or am i still going to end up wishing i had gone to 4.88s?

[Fordguy77]

My official plan in pure bullet forum-
*Ranger done by the end of this month
*Motor rebulid tranny swap for the 77 by the end of next month
*Take FJ60 Off The Road
*Spend Jan to June Build The FJ60
*Be Wheeling The FJ60 Sometime In July
*Buy A House Late Next Year

[Brody]

Hey Chris

Here is the link in the Yota make and model thread where I posted every damn bit of information I could find on doing disc brake conversions:

http://www.frontrange4x4.com/forums/showthread.php?8745-TOYOYA-INFORMATION-AND-LINKS/page2

If you have doubts, go with the 4.88s, especially if you may eventually plan on going with 37s. 4.88s and 37s are almost the ideal power/torque and you won't be too far off with the 4.88s and 35s. Maybe you should just suck it up and build the thing up for the 37s....

Like I said, 4.88s with 35s will put you at the high end of the power/torque/mileage curve, where 4.56s will have you right in the center. 4.88s with 35s will have you at the low end of the power/torque/mileage curve and dead nuts with 37s. You are more apt to feel the difference going up and down hills and see the difference in gas mileage...and we aren't talking a huge amount either way. Was me, I would go with the 4.88s. I am running 5.29s which put me at the low end with 37s, but the power band is good. I just suffer a little mileage. With anything bigger, like what I have now, 38s, I am dead center again.

I know more people who have the T case brake set up and like them than don't. Mid to late 80s Yota front calipers and rotors are a common choice, also for rear discs. There are diagrams for full size brackets in the disc brake conversion link if you want to go that route. Sky sells cheap brackets, but they are geared more towards a 1/2 ton Chevy caliper than Yota.

Rotating or locating the spring perches for an SOA ain't any kind of rocket science as some people would have you believe, either. Cut off the old perches, clean the axle, set the new perches on the axle in the same location in relation to the springs, rotate the axle until the drive shaft angle is nice and lined up, double check with angle finder, tack weld, check, then weld the **** out of them. If you have an option of getting oversize spring perches, do so, as they end up acting like a partial anti-wrap bar as well as allowing you the option of three holes to tweak your axle location. Do this for both the front and the rear..

[Fordguy77]

Hey Chris

Here is the link in the Yota make and model thread where I posted every damn bit of information I could find on doing disc brake conversions:

http://www.frontrange4x4.com/forums/showthread.php?8745-TOYOYA-INFORMATION-AND-LINKS/page2

If you have doubts, go with the 4.88s, especially if you may eventually plan on going with 37s. 4.88s and 37s are almost the ideal power/torque and you won't be too far off with the 4.88s and 35s. Maybe you should just suck it up and build the thing up for the 37s....

Like I said, 4.88s with 35s will put you at the high end of the power/torque/mileage curve, where 4.56s will have you right in the center. 4.88s with 35s will have you at the low end of the power/torque/mileage curve and dead nuts with 37s. You are more apt to feel the difference going up and down hills and see the difference in gas mileage...and we aren't talking a huge amount either way. Was me, I would go with the 4.88s. I am running 5.29s which put me at the low end with 37s, but the power band is good. I just suffer a little mileage. With anything bigger, like what I have now, 38s, I am dead center again.

I know more people who have the T case brake set up and like them than don't. Mid to late 80s Yota front calipers and rotors are a common choice, also for rear discs. There are diagrams for full size brackets in the disc brake conversion link if you want to go that route. Sky sells cheap brackets, but they are geared more towards a 1/2 ton Chevy caliper than Yota.

Thanks, i am checking some of the links now!
I think your right pete, i should suck it up, then worst case i am over built which typically isnt a bad thing. Once this all starts in January, i am probably going to be calling on all of that wonderful yota knowledge experience you have every once and a while! Thanks Pete!

[Haku]

I've been doing some reading about upgrading my brakes all around, and i found some stuff on using second gen 4runners calipers and masters for the brake setup. As far as a t-case or transmission brake i am not to concerned about. I personally have never had any bade experiences with either or, and know a few people using them and they have never said a bad thing about them.


Thanks for your offer! I'm actually going to be buying a new welder for this project! Well its for more than just this project but its giving me an extra reason to get it. I'm getting a new MIG, capable of running dual shield(makes welds look awesome!)! As well as a small TIG unit for when i build my exo(still planning on this though, good tig machines are expensive :frown: )

I've been thinking along the same lines with welding stuff too. I have the MIG already, but it would be nice to have the TIG. The one I have been looking at is a Multi Process unit from either Everlast or Longevity. That way I can use it for Plasma and TIG. If you don't care about doing Aluminum with it and don't need to cut more then 1/2" metal, you can get one for as little as $800. The AC/DC ones that can do Aluminum are more along the lines of $1200-1400. Still, considering that you get a 3 in 1 (TIG/Stick/Cut) for the same price that you get a Hypertherm or similar Plasma, its enough to ignore the fact that they are Chinese made.

As for the gears, I really like having Duals, but I find that its only really worth doing if you have 4.7 gears in one of the cases. That gives you a good range of choices for gearing. On stuff where I only plan on going 30-40 miles per hour, I'll throw the doubler on and stay in 2wd high range on the main case, and its nice for that. Then most of the time running the trail I'll put the doubler in high range and do the 4.7 gears until I hit a bigger obstacle where I'll do Lo/Lo. Marlin should have something that bolts right on I would think, but not sure. Says "its in the works" on their website, but not sure what the deal is.

For me, its a no brainer to go from for 37's over 35" tires. The Landcruiser axles are a bit beefier, so they'll take more abuse, though I would still get some Longfield 30 spline shafts. Once you get that big, you might as well take it all the way. Most guys I see on 35's in anything but a Samurai go with 37's or more for their next tires. That said, if you are wanting 35's, I will be selling the ones that the Pitbulls replaced (BFG MT KM's) with the 15" rims they are on.

[scout man]

Here is my :2c:, although it my be the unpopular advice. Research with people that have your exact rig as to the preference for gear ratio. People love to say that "x" is the correct gearing with "y" tires... end of story. This is NOT true!! i was told over and over that I needed 4.88s for my 35 inch tires. However, scout people were saying 4.56, and that is what I chose. With this gearing I am damn near red-lining my rig at highway speeds. If I had gone with 4.88s I would no longer be able to easily drive my rig to the trails and I would have been horribly unhappy with it. It all depends on engine redline (mine is low, 4000), transmission gearing, tcase gearing, etc. I dont know if this is the same from yota to yota to yota, but if it were me I would see what the other FJ60 guys have found to be a good choice, and go with that. Especially since this rig seems to be a DD more than an exclusive trail rig. And yes, even if you start with 35's you will probably want 37's, so take that into consideration. I was originally thinking 33s, so I went with 35s instead. NOW, I am already thinking my next tires with be 37s, although it will take a LOT more effort for me to fit those, so that is something to consider also.

[Brody]

Thanks Steve and good point.

I was speaking from a Yota owner's perspective for the most part. I have also used the 4.88/4.56 combo for 33-35" tires on a mess of other rigs, though not on the Scout I had. I actually never messed with the gears on that Scout, just stuck bigger tires on it and called it good.

So, bottom line, ANY tire chart out there is going to be a general "rule of thumb", whether it is from the Interco site, 4Wheel Parts, Off Roaders.com, Bryan's Yota site, etc., etc. Dave Nay, for instance, has 37s and 4.88s on his LC80 and is perfectly happy with them. I know other people who are perfectly happy with the 5.29s and 37s and actually prefer them over the 4.88s. One of the things that you are dealing with is the very torquey inline 6 that is in your rig, an engine not known for huge power, much like the Jeep 258. Another thing is, that on any Yota chart you find, it 90% of the time relates to the 22R/RE 4 banger. I would spend a bit of time Googling


Here is one link to a popular chart:

http://www.offroaders.com/tech/gear-ratio-chart.htm

Here is one for Toyotas:

http://www.off-road.com/trucks-4x4/tech/toyota-gear-ration-and-tire-chart-18931.html

And yet another one:

http://www.4x4offroads.com/gear-ratio-chart.html

Here is a link for reduction boxes/lower T case gears:

http://www.tlc4x4.com/new/tlc_rockcrwlg.htm

And another from Advanced Adapters:

http://advanceadapters.com/category/80/Toyota-Land-Cruiser-Low-Gearing-Options.html

Here is a set of gears F/R from Iron Pig Off Road with master install kits for $649 with free shipping:

http://www.ironpigoffroad.com//index.php?main_page=product_info&cPath=2_18&products_id=45

Not the best, but not the worst. I would price them through Randy's Ring and Pinion

I think you would probably be satisfied with 4.56s with either the 35s or 37s and maybe happier with the 4.88s with 37s. That is the way I would go. Like I said, do some research on the FJ forums like I H8TE Mud, research Man A Fre, Slee, Iron Pig Off Road, and TLC Cruisers for more information. Of course, if you are going to drop in a LT in the future, then anything relating to gears/power, etc you find for the Yota 6 is going to go out the window....

Oh...I ran across this nice article on an SOA for an FJ60:

http://www.off-road.com/trucks-4x4/tech/offroadcoms-land-cruiser-tech-toyota-land-cruiser-fj60-spring-over-19178.html

[Brody]

There is probably a bunch of stuff in the Yota tech section as I seem to remember someone else asking about this awhile back and I think I posted a bunch of links on it there. Here are some links:

Proffitt's Cruiser conversion parts stuff:

http://www.proffittscruisers.com/suspensions/spring-over-axle.html

Cruiser Outfitters Cut and Turn:

http://www.cruiseroutfitters.com/customfab.html

RuffStuff Specialities Kit:

http://www.ruffstuffspecialties.com/catalog/fj60-soa-kit-p-197.html

Pirate 4x4 FJ62 build thread/SOA w/pictures:

http://www.pirate4x4.com/forum/showthread.php?t=183005

Off Road.com article:

http://www.off-road.com/trucks-4x4/tech/offroadcoms-land-cruiser-tech-toyota-land-cruiser-fj60-spring-over-19178.html

Off Road.com X2:

http://www.off-road.com/trucks-4x4/tech/offroadcoms-land-cruiser-tech-toyota-land-cruiser-fj60-spring-over-19171.html?printable

Off Road.com X3:

http://www.off-road.com/trucks-4x4/tech/offroadcoms-land-cruiser-tech-toyota-land-cruiser-fj60-spring-over-19170.html

Pirate 4x4 FJ40 SOA article (you are going to be dealing with essentially the same crap)

http://www.pirate4x4.com/tech/spring_over/index.html

Keep in mind that this is one of those things that has been absolutely beaten to death, like fat tires vs skinny tires, tall tires vs simply oversized tires, shackle reversal vs regular lift, yada, yada, yada. They were beating all this stuff to death back when I started wheeling in the 70s and it hasn't stopped yet. What it comes down to is simply what do you want your rig to do, modifying it to fit YOUR needs, and learning to drive with the different driving characteristics that the modifications you do to it result in. All of these modifications, or lack of, work, and have worked for thousands of people.