SAS/SAC debate thread
- Thread starter flyingwil
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cruiseroutfit
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Most 4x4 van conversions I am familiar with use a standard Dana 60 and some HD transfer case be it 205/Atlas/D300, etc. Honestly both axle and t-case will be easier to source parts, from axle joints to hub components or t-case outputs. To that, its hardly fair to compare a true one ton+ t-case such as the Atlas used in the Sportsmobile with the factory transfer case used in the Tacoma. Don't get me wrong, the Tacoma t-case is a phenomenal design, stout and reliable... but not in the same league strength wise as an Atlas.
A low-height SAS will be difficult to build while maintaining a decent amount of suspension travel and load capacity. The SEMA truck was a perfect example of what an issue this could be, it literally had just inches of up travel. Doable, sure, costly and more customized involving non-standard parts, absolutely. For something I trailer to a Moab for a weekend for an absolute thrashing... wouldn't hesitate. For something dive from SLC to spend a week of overland travel in remotes parts of Southern Utah, let alone say South America... I would think long and hard about it. :ylsmoke:
Meh, this is debatable. And also varies greatly on driving style. If your trying to bomb through some desert roads, then IFS all the way. If your not on a speed mission and would rather have the slow crawling capability for say Rubicon, SAS. It's directly relevant the specific user's desires and goals. The choice to swap or not swap is really specific to each individual end user.
How much suspension up travel is really necessary? The same question arises with down travel....How much is necessary? With each system having clear advantages in each. You could go Stage 3 Total Chaos and have the capability to slaughter washboards with massive amounts of travel. On the converse run a SAS with 5 inches of up travel and 9 inches of sag, to flex like a slinky. Clear advantages to each. And clear weaknesses and point of failure in each. Neither with off the shelf parts.
And in either case..... Why not link up the rear too? You could run air shocks to keep ride height the same with whatever load your carrying, or you'd have the capability to tune coil-overs to your desired ride characteristics. It's only money.
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devinsixtyseven
Explorer
I'm drawn to these threads like a moth to a bug zapper...oh well.
What potential shortcomings of the IFS are you looking to overcome with a solid axle? If it's the drivetrain itself, then potentially there's a good reason...everything else has an aftermarket solution that works with the original drivetrain.
-Sean
What potential shortcomings of the IFS are you looking to overcome with a solid axle? If it's the drivetrain itself, then potentially there's a good reason...everything else has an aftermarket solution that works with the original drivetrain.
-Sean
SAR_Squid79
Explorer
I can't tell you how many people have tried to convince me that I should or need to SAC my Tacoma...
My whole thing is that IFS really is a lot stronger than most people think. As long as you're smart about what you do and how you do it, you don't need a Solid Axle unless you're wanting to do HARD CORE Rock Crawling, and need extreme articulation. On most overland adventures that I have seen, that much articulation is not needed. The greatest neccessity being reliability.
While I have not done much true overlanding, I have been to NUMEROUS large 4-wheeling events. At every event I've ever been to, most broken rigs that you see are SAC rigs, while IFS keeps soldiering along. SAC rigs break in a hundred different places for a millions different reasons...
I think a properly set up, and maintained IFS is the way to go. Proper gearing, proper tires, and the right suspension components will take you a million miles. (See Hytenor (TTORA), BajaTaco, Peter Parks, Expeditions West)
The best argument that I've ever been able to think of IN FAVOR of SAC is that you can walk into Billy-Bob's auto parts store ANYWHERE in the USA, and they're going to have Dana, Ford, and Chevy axle parts on the shelf. There are a lot of places that I've been to where a Toyota axle shaft would be VERY hard to come by.
:truck:
My whole thing is that IFS really is a lot stronger than most people think. As long as you're smart about what you do and how you do it, you don't need a Solid Axle unless you're wanting to do HARD CORE Rock Crawling, and need extreme articulation. On most overland adventures that I have seen, that much articulation is not needed. The greatest neccessity being reliability.
While I have not done much true overlanding, I have been to NUMEROUS large 4-wheeling events. At every event I've ever been to, most broken rigs that you see are SAC rigs, while IFS keeps soldiering along. SAC rigs break in a hundred different places for a millions different reasons...
I think a properly set up, and maintained IFS is the way to go. Proper gearing, proper tires, and the right suspension components will take you a million miles. (See Hytenor (TTORA), BajaTaco, Peter Parks, Expeditions West)
The best argument that I've ever been able to think of IN FAVOR of SAC is that you can walk into Billy-Bob's auto parts store ANYWHERE in the USA, and they're going to have Dana, Ford, and Chevy axle parts on the shelf. There are a lot of places that I've been to where a Toyota axle shaft would be VERY hard to come by.
:truck:
dlbrunner
Adventurer
Talk to Steve Shaeffer with Sonoran Steel and or check out his website Sonoransteel.com . He is out of Tempe. His 4runner has a Wagoneer Dana 44 in the front. He was one of the early SAS conversions on that gen of Toyota suspension. he has a good parts list and instructions etc..... Cool guy too.
4Rescue
Expedition Leader
I agree with alot of that wich has been said here already. But here's one thought I had:
Honestly if you'er taking off for a long trip. shouldn't most of the wear items be inspected and replaced prior to leaving for the trip??? What I mean by that is that typicaly a leaf-sprung (and that's the only way I would do an SAS for an expo rig) is going to have fewer wera items and will in turn have a longer service life under harsh conditions. I'm not saying thigs can't break unexpectedly and I definatly VERY much agree that when out in the wild it's better to ahve somehting that can be weld'd back together rather than requireing a new part be machined. B ut in general, when dione simply alot of the SAS trucks I'm familiar with require less routine maintenence than even completely stock IFS rigs.
My reasoning behind running a Leaf-sprung SAS is simply that that is the way Toyota made them for our "mini-trucks" and as Dave said you can literaly use almost ALL stock parts to do the swap. Most-importantly while Leafs might not flex or ride as smoothly as the Coil-link variety SAS's, they do silmplify the running gear and the axle-location issue. Plus I can bet it's alot easier to "bush repair" a leaf system and to limp out with a leaf suspension than if you say broke a link, TRE etc... That's just my opinion so feel free to dissagree.
From an IFS stand-point, I also very much prefer the old "T-bar" suspension that I have to the new "coil-over" IFS. While it may not ride as smoothly it certainly is one of the most robust IFS systems out there.
In general, honestly unless you're really pushing the rig I don't see to many catastrophic failures happening with a SFA and honestly who here carries a whole new sub-frame/A-arm eset-up with them??? Cause you know if you really messed up your IFS you're in the same boat if not worse with the IFS truck.
Cheers
Dave
Honestly if you'er taking off for a long trip. shouldn't most of the wear items be inspected and replaced prior to leaving for the trip??? What I mean by that is that typicaly a leaf-sprung (and that's the only way I would do an SAS for an expo rig) is going to have fewer wera items and will in turn have a longer service life under harsh conditions. I'm not saying thigs can't break unexpectedly and I definatly VERY much agree that when out in the wild it's better to ahve somehting that can be weld'd back together rather than requireing a new part be machined. B ut in general, when dione simply alot of the SAS trucks I'm familiar with require less routine maintenence than even completely stock IFS rigs.
My reasoning behind running a Leaf-sprung SAS is simply that that is the way Toyota made them for our "mini-trucks" and as Dave said you can literaly use almost ALL stock parts to do the swap. Most-importantly while Leafs might not flex or ride as smoothly as the Coil-link variety SAS's, they do silmplify the running gear and the axle-location issue. Plus I can bet it's alot easier to "bush repair" a leaf system and to limp out with a leaf suspension than if you say broke a link, TRE etc... That's just my opinion so feel free to dissagree.
From an IFS stand-point, I also very much prefer the old "T-bar" suspension that I have to the new "coil-over" IFS. While it may not ride as smoothly it certainly is one of the most robust IFS systems out there.
In general, honestly unless you're really pushing the rig I don't see to many catastrophic failures happening with a SFA and honestly who here carries a whole new sub-frame/A-arm eset-up with them??? Cause you know if you really messed up your IFS you're in the same boat if not worse with the IFS truck.
Cheers
Dave
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Bighead
Adventurer
X2. Yotatech might still have some of the write-up info he did while the conversion was going on. If I ever wanted to get a SAC done Steve would be the guy I would call.
shawkins
Adventurer
That is one of the main reasons I'm planning on SAS'ing my '91 4Runner. I'm tired of replacing parts that wear out all too quickly. It will be a low lift leaf swap where flex is not the main goal, strength and simplicity in ease of maintenance is.
ntsqd
Heretic Car Camper
As the owner of not one, but three live axle - leaf sprung 4WD's I fail to see any mystique in them. I think it's a greener grass thing. Right now I need to replace the trunnion bearings in the pick-up. I put those Koyo bearings in less than 3 years ago and they're done. They have been brinnelled, they have 'detents' in them. Both knuckles are slightly leaking too. Did those seals and the inners when I did the steering bearings. Now I do hammer on Patch on occasion, like when the race truck rolled and we had no idea of injuries because the roll took out their radio antenna, but 3 years isn't very long for those bearings to last. This on top of the normal oil changes, brake maintenance, etc. Look up "knuckle rebuild" on 'Mud. It's not a fun job. It's very messy and time consuming for the gain. I could swap out ball joints with 1/16 of the mess and 1/4 of the time. So tell me where the lower maintenance with a live axle thing is , because I'd like to know.
Eventually one of these trucks will sell or get parted out. The other two are both slated to get radius arms & coil springs at some point in the future. I'm in no rush. For the same development effort that I've put into making one of those two trucks ride in a civilized manner I could have a really plush and capable IFS that would do everything that I currently ask of the live axle, and ride smoother in the process.
Maybe I should go looking for an '86-'88 Xcab frame........
Eventually one of these trucks will sell or get parted out. The other two are both slated to get radius arms & coil springs at some point in the future. I'm in no rush. For the same development effort that I've put into making one of those two trucks ride in a civilized manner I could have a really plush and capable IFS that would do everything that I currently ask of the live axle, and ride smoother in the process.
Maybe I should go looking for an '86-'88 Xcab frame........
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shawkins
Adventurer
It probably is the greener grass thing. But after my last rebuild of the IFS, I've gotten maybe 50K miles out of it. And I have never gotten it to be as "tight" as it used to be.
I plan on making my swap as plush as possible with custom Deaver leafs and King or Fox shocks.
tdesanto
Expedition Leader
tacollie
Glamper
If you you do it right I think it is worth it. I would definitely go coils with radius arms and not leaf. As far as parts go if you spend the money and use a diamond housing with 80 parts inside then most your breaking points would be toyota factory parts right? On 05+ tacos I don't see the height as big of an issues since my 05 with OME is about the same height as my stock 02. I would like 2 or 3 more inches of height. The older trucks get tall fast but I think a truck in the 4 to 5" lift range would be about right. I think solid axles are stronger than IFS but once people SAS they take different routes and harder paths so they end breaking just as many parts. Also a lot of people do "budget" SAS and that doesn't do any good(a local shop said If I supply the axle they could do the swap under $1500).
From my experience the torsion bar IFS is beefier than the coilover IFS. I never had IFS issues with my 90 4Runner. As far as the IFS being the design yota engineers spent so much time planning; expo travel and frequent offroad use was not the "intended" use for these trucks.
If I had the money to do it right I would have already done the swap. Right now my truck does what I want it to, it just takes a little more work and planning. I have not had good experiences with reliability on solid axle vehicles outside toyota. The jeep(2002), discovery(1995), and d90(1996) were awesome when they were running and fun to drive but they left me stranded regularly. A toyota has never given me problems. Sorry for typing a lot and not saying much this is just what goes through my head frequently.
From my experience the torsion bar IFS is beefier than the coilover IFS. I never had IFS issues with my 90 4Runner. As far as the IFS being the design yota engineers spent so much time planning; expo travel and frequent offroad use was not the "intended" use for these trucks.
If I had the money to do it right I would have already done the swap. Right now my truck does what I want it to, it just takes a little more work and planning. I have not had good experiences with reliability on solid axle vehicles outside toyota. The jeep(2002), discovery(1995), and d90(1996) were awesome when they were running and fun to drive but they left me stranded regularly. A toyota has never given me problems. Sorry for typing a lot and not saying much this is just what goes through my head frequently.
Rexsname
Explorer
Wil,
I'm really happy with my Marlin Crawler....It allows me to drive soooooo much more 'gently'. I think with a front locker and 33" tires it would do any thing I could imagine wanting to do. You allready have such a cool truck, I'd hate to see you have to miss out because it was on jackstand alley. When you are up here for the Exposition I'll see if I can't tear you away and have you try it out.
REX
I'm really happy with my Marlin Crawler....It allows me to drive soooooo much more 'gently'. I think with a front locker and 33" tires it would do any thing I could imagine wanting to do. You allready have such a cool truck, I'd hate to see you have to miss out because it was on jackstand alley. When you are up here for the Exposition I'll see if I can't tear you away and have you try it out.
REX
4Rescue
Expedition Leader
Even a Leaf-sprung Live axle will MASSIVELY out flex an IFS rig. I tend to agree that people see these SFA'd trucks out crawling and get a far away look in their eyes, and yes I think that they're way over-hyped espescialy among this crowd that really needs the smoothness livability of the stock IFS far more than the Extreme flex an SFA gives you...
BUT:
They are far more durable over time and have fewer easily worn parts. My ascertion of using a leaf sprung set-up is that it simplify's the system compared to some of the often drooled over multi-link C/O itterations out there. Having leafs, to me is a durability and simplicity issue. Like I said, it's far easier to limp out with a hobbled together leafpack then with a broken radius arm. Not that either is fun, but one is certainly easier.
Honestly from a "Ride" stand-point I think it comes down to the particular driver more than anything. To me, I LIKE a "truckish" ride and actualy expect it... that's why I bought a TRUCK. I always fnd it funny whaen people complain about the rough ride etc... Same with the noise and the handeling. Drive slower and pay attention to the vehicle. It's pretty clear that vehicle dynamics are a lost art to the average Red-White and Blue'r. It's a truck, and all of this griping and "wussifying" of the modern 4x4 is what leads auto-makers to make garbage like the H2 etc. and NOT offer us things like the HDJ80/105 etc. because Americans are SOFT. Hate to say it, but we are, it's readily apparent by our buying stats...
Cheers
Dave