SPUA (SPring Under Axle)
Pro's:
* Cheaper
* Easier to install
* More stable in turns / jumps - Sean Devinney's (of Aftermarket 4x4) race rigs are mostly (all?) SPUA for this reason
Con's
* Less leverage on the suspension (doesn't articulate as easily)
* More things below the axle = more things to snag on rocks / drag in mud
* Only good to about a 31" tire (maybe 33" if you don't fear fender cutting, & BFH)

SPOA (SPring Over Axle)
This re-locates the leaf springs above the axle. This action automagically lifts the rig 3 to 4.5" - neat eh?
Pro's:
* "Cheap" way to gain big lift numbers
* Suspension articulates easier (it's a physics / leverage thing)
* Moves more of the bits out of the way of rocks & mud
* Virtually unlimited on the upper limit of tire size
Con's:
* Cost (see hidden costs below)
* Generally requires more tools & higher mechanical skill set
* More body-roll in turns

Below I'll break down the SPOA into "minimal" and "proper / complete" conversions. Going from SPUA on 29" tires to SPOA with 31" can EASILY be $1000 more in TIRES & WHEELS ALONE. Minimal setup is my (non-engineer) opinion on the minimum needed to safely get down the road. I am NOT an advocate of doing the minimum needed for SPOA. If you're just looking for height to mall-crawl, go with taller springs and / or body lift. If you're wanting it to go off-road, just doing the minimum is cutting corners on usability & reliability. I also tend to round up / include estimated shipping for heavy items (Remember: this article is about hidden costs). Can it be done cheaper if you have the right tools to fab stuff on your own? Sure. Might you have a friend's cousin's borhter's uncle that can give you free parts? Sure. But again - that's not what this article's about.

NOTE: I'm a HUGE advocate of doing lockers before lifts & tires.

The minimum needed to technically / safely run a SPOA:
* Spring perches
This is what your leaf springs are going to sit on. They're also used to center / locate the springs properly.

* Drive shaft spacers
If you don't use these, drive lines fall apart.

* Extended break lines
So you don't rip out your break lines when the axle drops in a hole.

* Steering correction
Re-locating the axles in the suspension changes the geometry of the steering system - making it difficult to control the vehicle. At minimum, a Z-link bar should be used. Over The Top (OTT) steering re-locates steering components up and out of the way of things like rocks (which tend to bend / break steering components).

* Re-locate shock mounts

There are many many kits out there (most of them are far from complete), but there's kits that have the above bits in the neighborhood of $600 shipped (minimum).

* Tires: $750
All five of them. By far, tire failure is the #1 failure off road. Along with your tire repair kit (you do have a tire repair kit, and ability to inflate tires right?), a full sized spare to get you home is a must. A full sized spare is especially critical when running a non-selectable locker. Let's not forget tire installers like to gouge you for mounting and balancing M/T tires.

* Offset wheels: $550
Wider tires need to be moved away from the frame (to keep from rubbing).

Anything less than 31" on a SPOA looks dumb, so let's do our baseline price |removethispart||removethispart|@ $1300 for five 31" Super Swamper tires mounted & balanced on cheap steel wheels. Add that to our minimal SPOA kit, and we're up to about $2,000.


The bits that make it a proper SPOA:
* Shocks: $80+
Stock shocks will limit suspension travel. Think cheap here ($15 - $50 per shock). More expensive shocks provide more resistance to suspension travel - good for heavy rigs, BAD for light vehicles like ours. People report good success with Monroe, Napa and Doetsch DT3000 shocks.

* Bump stops: $100
Needed to keep your springs from moving the wrong way & destroying them.

* Gearing correction (T-case, diff, both): $400-$1,000
Suzuki engines love to rev, so it's especially important to be geared properly (improper gearing KILLS power & MPG). Samurai has is the only transfer case that reduces both hi and low range. This is fantastic news, since you can re-gear for street use, and automagically be reduced (even lower than stock) in low range! It's up to you what's more important: value, or reliability.
Another hidden cost: Breaking open the diff or the t-case = new fluid & rebuild kits ($100)

Don't forget about...
* Power Steering: $250
If you ever plan on running any real trails which require aired down tires - power steering is the only way to fly. I've boiled over my power steering with 29" tires, so now every rig I run how P/S coolers ($50). And, let's not forget the price of P/S fluid ($10).

* Swing away tire carrier: $500
Four options: a) Keep the larger / heavier tire on the tailgate, and risk ripping it off. b) Moving the tire into the vehicle and killing a lot of valuable storage space. c) Move the tire to the roof and raise the center of gravity. d) Install a swing-away tire carrier that transfers the weight to a heavy-duty bumper (which is tied to the frame). Proper SPOA = option d.

* Stronger axles: $250+
Stock axles are generally accepted as safe up to 31" (all of this depends on your driving style, terrain & a little luck). A few can make 33" survive reliably. The most common upgrades are Trail Tough's Double Toughs, Toyota axles, or Dana 44. Double Toughs are stong, relatively cheap, and the easiest to install. Full axle swaps are more difficult, but open up more locker / gearing / axle possibilities. Toyota (easier to adapt) and Dana 44 (a bit harder) are the most common axle swaps.

* Armor: $300-$2,000
A must-have for rock crawlers, and probably useful for anyone else planning on off-pavement fun. Rock sliders, axle trusses, t-case and diff protection add up $$$ quickly. A roll cage will double armor costs (but my head's important to me).

* Bigger breaks: $300+
I can definitely feel a difference between my stocker & my SPOA'd rig on 31" tires. Breaking distance is increased, and it's more difficult to keep the tires from locking up (and therefore loosing control) in inclement weather. IHMO upgrading the breaks is a "should do" with 31"+ tires, and a "must do" for people with 33"+. yeah yeah - safety's boring, but it's also important. Hidden cost: e-brake kit, new pads & fluid. May require upgrading the break master cylindar as well ($100+).

Can you see how quickly a complete & properly setup SPOA will easily get into the $3,000 "true cost" range? We haven't even got into other spring options (RUF, CJ, YJ, Toyota, coil & links, shackle reversal...). And, you've already installed that locker right?

Brent |removethispart|@ Trail Tough disagrees with me on the T-case / Diff gear issue. His thoughts:
http://www.trailtough.com/index.php?view=article&catid=36:techinfo&id=60:gears&option=com_content&Itemid=60

I disagree about there being a proper SPOA lift.  Everyone has their own way of doing it, sometimes you need to just play with it to find out what works for you.  A "proper" conversion is one that accomplishes what you set out to do and does it safely.

As for the shocks, you can simply swap your spring pads from right to left, this will allow your shock position to remain the same as a stock vehicle.  You will not gain any additional travel, but they will work fine.

Power Steering is nice, but not required.  I have run 33"x12.5" tires with manual steering for 4 years and have not had any issues.  It does get harder steering when locked.

A lot of the items listed are more for upgrading your vehicle rather then what is needed for the SPOA conversion.  That being said, I would add a Roll Cage to the list of things to add to your vehicle.

Having owned at least 6 Samurais, most of them SPOA that I did myself, I have to agree with the above reply. While the OP did have some good things for people to think about, most of the additional costs are unnecessary. Instead of $500 for wheels, use a set of Ford truck or CJ wheels. You should be able to get a good used set of wheels for under $100. Much less if you find someone who upgraded wheels. For shocks, I always buy the cheapest I can for a Samurai, and when going SPOA, I use 70's Dodge truck rear shocks. Easy to find at any part's store, have a LOT of travel for off the shelf shocks, and by using cheap brands, they are still very soft. Custom shock mounts are required for these, but if you are doing your own SPOA, fabbing shock mounts is nothing.

I would add in that some type of torque arm is a good idea for the rear axle. Axle wrap is the easiest way to trash the rear springs.

Tire cost is minimal if you plan it right. If you have a stock rig, you will be upgrading tires no matter how high you go. And buying cheap 31s or even 33s doesn't add a ton over buying 29" off road tires. So just plan ahead, and think about what you want to do before you start modifying the vehicle. 29" tires will run around $90+ in my area, and I can get cheap 31s for $110. Thats only $80 more for a set of 31s over 29".

Brakes: With stock brakes in good condition, I never had a problem locking up 33s. Yes, there is more pedal effort, but not a safety issue. Rear disks are nice, but aren't necessary. I was actually quite impressed with the Samurai brakes. My Samurais on 33s stopped better than my '98 XJ with 34".

As with any modification, you can take a SPOA as far as you want and add all kinds of costs to it. But a basic SPOA can be done very cheaply, which is why its the most common lift I've seen on a Samurai.

Jim

Yes but a SPUA lift done with all the goodies will out perform a SPOA lift done on the cheap every time.

The OP wasn't even doing a fair comparison. He was comparing a SPOA (5" lift minimum, do the measurements- (axle diameter) + (spring pack thickness) + (2x spring pad thickness) to a couple inch spring lift. If the comparison was fair, compare the same lift numbers- say 5" for each- and the SPOA comes out much better. Both require the same steering, shock, driveshaft, and brake line modifications. The difference is, you save the cost of the springs with a SPOA, and the SPOA is softer, rides better, and flexes better than a heavily arched spring pack. I used all of my Samurais as daily drivers, and drove (not trailered) them to every event- trail runs and mud bogs, even several hundred miles away.

If all you want is 2 or 3" to fit some 31s, then fine, go with a spring lift. The overall cost will be about what a 5" SPOA costs, but you will have less off road capability. Still a decent way to go for a daily driver and moderate off roader.

Jim

I like the "no stone left unturned" approach. Nice write up jeremiah. Myself I dont like to incorporate random parts or mix and match. Nothing like being on the phone w/ the parts house and not being able to remember what year make and model you need a thingamajig for!!

Great comments guys. I wanted to clairify a few things...

This article is more of a "thinking piece" and sharing some of my personal experiences. Different people have different places they're wheeling (and therefore have a broad range of needs), budgets, fabrication skills, access to equipment etc. The things I listed are things people should be taking into consideration. SPOA and SPUA is an apples & oranges comparison. And, yes, SPOA at a certain lift height is (economically) a better choice... which is why I tended to use smaller tires with the SPUA, and larger with the SPOA. This article wasn't intended to be "all inclusive" of every possible lift option / combo. It was intended to help people who may not realize there's more to a lift than spring purches & extended break lines.

I know when I took the leap to SPOA, I had a different set of financial & finctionality expectations. I read over and over again how people did a SPOA "on the cheap". And, I learned that on the cheap can = stuck on the trail. Or, that they were talking about JUST the lift, and not really accounting for the "complete" cost of the lift. For example:
* I consider non-stock "sets" of tires & wheels to = 5 not 4. A stock 27" passenger tire isn't very helpful if the other tires are 31"+ M/T. Tires seem to be one of the biggest failures people experience on and off pavement, so I consider a useful spare a "must have" item.
* Around here, the difference between a 29" TSL and 31" TSL is about $85 ea x 5 = $425
(http://www.4wd.com/productdetails.aspx?jeep-sid=0&plID=456&partID=16229)
(http://www.4wd.com/productdetails.aspx?jeep-sid=0&plID=456&partID=16232)
If they can be found for less, I'm all for hearing about it. I have to get a new set soon  :'(
* Generally speaking, one can use stock wheels for 29" tires, but may need to run a different offset for 31"+ tires (x5 not x4). Again, something to consider.
* I believe I forgot to mention the hi-lift jack that's needed to swap out larger tires. A $50+ item.
* I personally believe running better breaks with bigger tires is still a good idea. Can the big tires be locked up with the stock breaks? Sure. But, locking up tires is a bad thing. It's not the best way to come to a quick & controlled stop. Larger breaks give a better "feel" to the pedal. This feedback allows the driver more control in an emergency-stop event. I've especially noticed the difference in bad weather - I can stop much more easily without locking up.
* Power steering is a "luxury item". I'm an average build. With the 31" tires, my arms get quite tired when the tires are aired down, or if I'm in sand. Some people have no problems with 33" tires and no power steering. I'm sure this depends on a persons build, their tires, and where they're wheeling.
* I ran a z-link for steering correction. My steering linkage was exposed, and a rock are my steering. I was stuck 3+ hours down a trail. Fortunately someone had a torch, and brazed my steering linkage back together, and we used a strap to band-aid my TRE, and get me to the trail head. I learned the lesson: steering is CRITICAL, buy over the top steering.

Again, the writeup is from my personal experiences, expectations, and wheeling conditions... all of which vary. The point of this wasn't to bash SPOA or to try and discourage anyone from doing a SPOA lift. The point is to expose what possible hidden costs someone may face, and to allow them to make a decision about what fits their needs.

The OP wasn't even doing a fair comparison. He was comparing a SPOA (5" lift minimum, do the measurements- (axle diameter) + (spring pack thickness) + (2x spring pad thickness) to a couple inch spring lift. If the comparison was fair, compare the same lift numbers- say 5" for each- and the SPOA comes out much better. Both require the same steering, shock, driveshaft, and brake line modifications. The difference is, you save the cost of the springs with a SPOA, and the SPOA is softer, rides better, and flexes better than a heavily arched spring pack. I used all of my Samurais as daily drivers, and drove (not trailered) them to every event- trail runs and mud bogs, even several hundred miles away.

If all you want is 2 or 3" to fit some 31s, then fine, go with a spring lift. The overall cost will be about what a 5" SPOA costs, but you will have less off road capability. Still a decent way to go for a daily driver and moderate off roader.

Jim

SPUA, set up correctly flexes and rides amazing. If you choose an appropriate spring rate for the weight of your rig. You can have a somewhat arched spring, that is long and flexes well. 

my .02

Amilla

Sean Devinny's racing rigs are SPUA for stability reasons.

I am new to the zuki world ,,, just read this thread, it is packed full of good info,,,I THINK,,, my question is about the age of the post,,,with this information being so old is it still good info or are there better options now?

Sending a PM to Jeremiah,,

GRAYMAN SPOTTER

Hi,

I would also like to know if after 3 years this is still the best advice.  It still sounds very solid, but you know how time changes perspectives.

I'm hopefully picking up a Swami tomorrow that is stock.  I'm planning on running 31's and it will be a daily driver.  Looking for a good riding lift.

Rob

I did a spoa on my sammy i didnt have drive line spacers and havent had a problem, been running it this way for 4 years.
Ive wheeled with spua sammys "done right" and they couldnt keep up with me,
P.S. I dont have more than $175 into my lift

Good article. Still very relevant.
Don't forget the track bar.
 The stability issue is a red haring. Any lifted rig will loos a certain amount of stability.
 The higher the lift , the greater the loss. You should be looking for : is it stabkle enough for my driving needs and is it safe.
I run a SPOA, Ruff, High steer, long shock, ETC. ETC. on my 88 1/2 with no stability issues........ON OR OFF ROAD.
 The SPOA vs the SPUA debate is really  about technical expertice.
 SPUA: off the shelf, easier to set up BUT restrictive in many ways.
 SPOA: Can be off the shelf but recomended, Requires a lot more expertice to set up, much less restricted suspension.
.....Boxcar....