Front suspension geometry questions in regards to a SAS. (1 Viewer)

[baldilocks]

Doesn’t the aftermarket offer upgrade front suspension parts that will address those durability concerns and possibly even improve wheel travel?

I’m not sure how concerned you are about body damage but once you have successfully SAS’d your gigangabus and realize improved confidence and wheelability you’ll find yourself pushing the rig harder down trails is won’t naturally fit and then you’ll be explaining to your wife why her door won’t open anymore.

 

[Dindu Nuffin]

You said scrub radius is a concern for you. 80 axles have gotta be narrower than the sequoia axles and in that case you’d using wheels with a lot of offset and/or wheel spacers to match the rear axle width.

Have you considered a LC 200? Still IFS but more robust no doubt and I know that Slee has SAS’d at least one. I don’t know a lot about the 200 but if the drop is passenger like every other LC that fact alone would simplify matters and you’d be back into a Land Cruiser.

I'm having a hard time finding an accurate front WMS measurement for my front end without going out and measuring it myself. The rear is 66", so for the time being, I'm using that as the front measurement. Here's the math I've done so far: 63.3" for the 80. Offset on 80 wheels is 0, and the offset for the tree wheels is 15mm. Off the bat, I'd need 15mm spacers. 63.3" + 30mm = 64.5". I figure that could either be good enough or since I'm cutting the balls off, have 0.75" extensions made to go between the balls and the housing. I've read that there's some wiggle room on moving the inner axle shafts around a bit, but for now I'm going to assume new axle shafts. I'm OK with that because Tom Woods is about ten miles away and I was told that they can also modify axle shafts. If not then I know there's a few aftermarket options.

Thought about an LX570 real hard, to the point of test driving a few recently. Beautiful trucks but I feel like it'd be a shame to send one out onto the trails to get all scratched up. As nice as it would be to have something that nice for the trail, it's not needed as we have a few other really nice cars to drive on the street. Also, the tree's paid for and already has the lift, locker, gears, tires, and has some nice Rocky Mountain pinstriping. It's basically a SAS away from being the perfect rig for my needs. Cost of entry into an LX570 is, oddly, less than a 200 around here, but is still in the 25-40k range and the thought of that money sitting in our investment portfolio is more appealing than an LX sitting in the driveway.

When I was on the hunt to replace the 80, my first stop was a 100 and the main impetus for the change was more interior room. In that regard, the 100 felt more like a lateral move from the 80. If the tree had the same suspension as the 100 (or at least lower ball joints facing the correct direction), this thread wouldn't exist.

I agree with @baldilocks, you're most likely in uncharted territory.

Head to re-read your book to even find your question


You haven't said what your intended use is for the car once modded.

Is it a family tourer? Does it do daily soccer mom duties?
Are you prepared to let the wife loose in it with a car load of kids?
Is it a trail rig?

I'd suggest put the sequoia on a set of scales, figure out weight distribution to front and rear axles of both an 80 and sequoia.

I have no idea how a sequoia compares to an 80 in terms of overall weight, and engine weight etc. But one thing that will have an impact is going to be weight distribution, and unsprung weights.
If you put all 80 front end in, unsprung weight will be the same.
If the sequoia is heavier on the front axle, you'll need to look at spring and shock rates to get it to perform the same.
Even then, a difference in COG, width, length, weight, unsprung weight, spring rates, sway bars etc etc is all gonna play a part.

The higher you lift it, the more likely it is you'll get funky handling.
I'd guess sequoia will be heavier. Most new cars in general are heavier than 30 year old cars of comparable size.

Does 4" lift on the sequoia equate to 4" lift on an 80?
Compare height from ground to underside of frame maybe as a reference point for height comparison.
4" lift on an 80 is putting you into unstable territory IMHO, others will disagree, but there's loads of stories here if rolled, lifted 80's.

By the time you me about cleaning a stock housing so it's a bare housing, then modifying WMS width, you would save a lot of work and pain with a custom housing.

When 100 series where the new kid on the block, a few SAS conversions where done. Not really a viable option for most. Frame rail design is very different for a factory SAS vs factory IFS.
After people came to terms with IFS suspension in the 100s, and realised they still go 98.5% of the places a solid axle 80 would go, the aftermarket took care of some upgraded parts.
SAS just became a "did it because I can" proposition.

Definitely in uncharted territory regarding the 80 axle swap. I've seen a growing number of SAS'd Sequoias online, but they're all leaf sprung on full width tons. The intended use is focused on medium difficulty trails with an emphasis on safety, reliability, and comfort. It still spends more time on pavement than dirt, so it still needs to retain some sense of civility. No soccer mom duties and my wife has no problem driving it. After seeing the second truck with the popped ball joint, she said, "time to get that SAS project going."

Re: scales and weight... It's within a couple hundred pounds of stock curb, so I'd guess 5700- 6000 lbs. No idea on the bias so I'll have to get that data. Off the top of my head, the 2UZ is a couple hundred pounds less than the 1FZ.

I'm not sure what you mean by your 4" question. I went with 4" to clear the 35's, but in hindsight could have probably gotten away with a 2" lift. I agree about the 4" lift being questionable on the 80. I only had a 2" lift on the ones I had but a friend had a 4" lift and that thing was borderline scary. The 4" lift on the tree feels about as stable as the 2" lift I had on the 80s. I think the reduced engine weight and wider track has something to do with it.

I also agree about IFS vs. SAS and that SAS is more gratuitus at this point. But again... weak balljoints are enough to justify it in my mind, let alone all the other medium duty stuff in there like one double race wheel bearing, CV axle shafts that tend to pull apart at much more than stock droop, no option for a steering damper (I feel it does need it despite being R&P), upper ball joints, bla bla bla.

If it were my project I’d figure out what WMS width I was targeting, where I could fit a steering box, where I could fit a track bar, and I’d start a spreadsheet with a list of axle housing options that have near correct WMS, correct side drop, and steering knuckles that could work with my steering and track bar angles based on my plan and start weighing the time and dollar costs for housing purchase and fabrication hours to make it work.

A radius arm setup is going to handle like a radius arm setup, assuming that you get the arm lengths and angles close. Track bar and steering angles will have a lot of effect on body roll and bump steer and your IFS frame will likely need reinforcement for solid axle steering and track bar mounts and forces. You can’t copy the 80 track bar and steering setup directly because the drop is on the opposite side so track bar bends to clear the pumpkin are all wrong.

What’s your steering and track bar plan and geometry? Share a sketch and some photos.

Please see at the top of this post for the WMS measurements. As far as axle housings, this is probably going to get a lot of eye rolls but I absolutely hate how Dana axles look. I know that's really a stupid reason to pan what would easily cut the project time by half, but whenever I see a Dana, I think about some brodozer jeep or cheap ass leaf sprung SAS hack job. Money/time/skill was brought up somewhere in this thread and the short of that is I have plenty of all three. Cost is a concern, but I don't mind paying a premium for something I'm proud of. Cutting all the brackets off the 80 housing, modifying the 3rd member mounting face, flipping the front cover, installing a new drain plug, flipping the balls and probably extending the housing to get the WMS I'm after isn't a factor to me. A friend is a DoD machinist and has access to government tools after work hours, so making any custom parts is not an issue, should the need arise.

I'm taking the geometry the most seriously, hence the hidden question in the original post. I want to replicate Toyota's engineering as closely as possible because I know just how good the 80 front end works for me. However, I haven't actually started taking any measurements yet.

Doesn’t the aftermarket offer upgrade front suspension parts that will address those durability concerns and possibly even improve wheel travel?

I’m not sure how concerned you are about body damage but once you have successfully SAS’d your gigangabus and realize improved confidence and wheelability you’ll find yourself pushing the rig harder down trails is won’t naturally fit and then you’ll be explaining to your wife why her door won’t open anymore.

There are long travel kits and uniball solutions. LT is out of the question and I'm not convinced that uniballs would be good for me due to the perceived maintenance involved. They also wouldn't eliminate all the other drawbacks of what is really a medium to light duty IFS design. For what they cost, I could find a clean complete 80 axle.

 

[alia176]

This thread has been educational, and I might add that the SAS event is in Ouray next week. You might wanna check it out just to see if someone has done this already and copy their design. I see that you're out of UT so not too far for a lot of free feedback and some camping!

Carry on!!

 

[Broski]

The event in Ouray SAS is a great event but mostly older solid axle rigs 40s & 60s and some 80s = Solid Axle Summit

I have attended the last 3 years and will be this year as well. I have only seen 1 SAS = Solid Axle Swap rig in all those years and it's a 100 Series with a three link.
Same guy the last two years.

It's not a hard core crowd mostly clean older rigs.

 

[baldilocks]

I'm having a hard time finding an accurate front WMS measurement for my front end without going out and measuring it myself. The rear is 66", so for the time being, I'm using that as the front measurement. Here's the math I've done so far: 63.3" for the 80. Offset on 80 wheels is 0, and the offset for the tree wheels is 15mm. Off the bat, I'd need 15mm spacers. 63.3" + 30mm = 64.5". I figure that could either be good enough or since I'm cutting the balls off, have 0.75" extensions made to go between the balls and the housing. I've read that there's some wiggle room on moving the inner axle shafts around a bit, but for now I'm going to assume new axle shafts. I'm OK with that because Tom Woods is about ten miles away and I was told that they can also modify axle shafts. If not then I know there's a few aftermarket options.

Thought about an LX570 real hard, to the point of test driving a few recently. Beautiful trucks but I feel like it'd be a shame to send one out onto the trails to get all scratched up. As nice as it would be to have something that nice for the trail, it's not needed as we have a few other really nice cars to drive on the street. Also, the tree's paid for and already has the lift, locker, gears, tires, and has some nice Rocky Mountain pinstriping. It's basically a SAS away from being the perfect rig for my needs. Cost of entry into an LX570 is, oddly, less than a 200 around here, but is still in the 25-40k range and the thought of that money sitting in our investment portfolio is more appealing than an LX sitting in the driveway.

When I was on the hunt to replace the 80, my first stop was a 100 and the main impetus for the change was more interior room. In that regard, the 100 felt more like a lateral move from the 80. If the tree had the same suspension as the 100 (or at least lower ball joints facing the correct direction), this thread wouldn't exist.



Definitely in uncharted territory regarding the 80 axle swap. I've seen a growing number of SAS'd Sequoias online, but they're all leaf sprung on full width tons. The intended use is focused on medium difficulty trails with an emphasis on safety, reliability, and comfort. It still spends more time on pavement than dirt, so it still needs to retain some sense of civility. No soccer mom duties and my wife has no problem driving it. After seeing the second truck with the popped ball joint, she said, "time to get that SAS project going."

Re: scales and weight... It's within a couple hundred pounds of stock curb, so I'd guess 5700- 6000 lbs. No idea on the bias so I'll have to get that data. Off the top of my head, the 2UZ is a couple hundred pounds less than the 1FZ.

I'm not sure what you mean by your 4" question. I went with 4" to clear the 35's, but in hindsight could have probably gotten away with a 2" lift. I agree about the 4" lift being questionable on the 80. I only had a 2" lift on the ones I had but a friend had a 4" lift and that thing was borderline scary. The 4" lift on the tree feels about as stable as the 2" lift I had on the 80s. I think the reduced engine weight and wider track has something to do with it.

I also agree about IFS vs. SAS and that SAS is more gratuitus at this point. But again... weak balljoints are enough to justify it in my mind, let alone all the other medium duty stuff in there like one double race wheel bearing, CV axle shafts that tend to pull apart at much more than stock droop, no option for a steering damper (I feel it does need it despite being R&P), upper ball joints, bla bla bla.



Please see at the top of this post for the WMS measurements. As far as axle housings, this is probably going to get a lot of eye rolls but I absolutely hate how Dana axles look. I know that's really a stupid reason to pan what would easily cut the project time by half, but whenever I see a Dana, I think about some brodozer jeep or cheap ass leaf sprung SAS hack job. Money/time/skill was brought up somewhere in this thread and the short of that is I have plenty of all three. Cost is a concern, but I don't mind paying a premium for something I'm proud of. Cutting all the brackets off the 80 housing, modifying the 3rd member mounting face, flipping the front cover, installing a new drain plug, flipping the balls and probably extending the housing to get the WMS I'm after isn't a factor to me. A friend is a DoD machinist and has access to government tools after work hours, so making any custom parts is not an issue, should the need arise.

I'm taking the geometry the most seriously, hence the hidden question in the original post. I want to replicate Toyota's engineering as closely as possible because I know just how good the 80 front end works for me. However, I haven't actually started taking any measurements yet.



There are long travel kits and uniball solutions. LT is out of the question and I'm not convinced that uniballs would be good for me due to the perceived maintenance involved. They also wouldn't eliminate all the other drawbacks of what is really a medium to light duty IFS design. For what they cost, I could find a clean complete 80 axle.

How about an and LS packed 80 and rethink how much cargo space you actually need?

 

[alia176]

The event in Ouray SAS is a great event but mostly older solid axle rigs 40s & 60s and some 80s = Solid Axle Summit

I have attended the last 3 years and will be this year as well. I have only seen 1 SAS = Solid Axle Swap rig in all those years and it's a 100 Series with a three link.
Same guy the last two years.

It's not a hard core crowd mostly clean older rigs.

My daughter will be staying with me at SAS with her 3rd gen 4runner and she's hoping to see a SA swapped 3rd gen. Will keep our fingers crossed!!!

 

[Broski]

My daughter will be staying with me at SAS with her 3rd gen 4runner and she's hoping to see a SA swapped 3rd gen. Will keep our fingers crossed!!!

Are you staying at the KOA ?

Would be great to hit some trails with you !

 

[Dindu Nuffin]

This thread has been educational, and I might add that the SAS event is in Ouray next week. You might wanna check it out just to see if someone has done this already and copy their design. I see that you're out of UT so not too far for a lot of free feedback and some camping!

Carry on!!

I'd be down to attend next year; not enough lead time now. But the non- hard core owners of older rigs sounds like my tribe. I don't need a gnarly trail to enjoy the day. Even better when everyone else is likeminded and nobody breaks anything.

How about an and LS packed 80 and rethink how much cargo space you actually need?

I thought long and hard about all that before selling the 80, and it was not an easy decision especially since I paid $3500 for a clean 3X locked '95 in 2015 and had it dialed in where I wanted it. I was so on the fence about it that I had the tree for almost six months before I decided to commit to it and sell the 80. I considered an engine swap, looked hard at a way to integrate rear AC, and did everything I could to convince myself to keep it but in the end, the tree just fits our needs better. It's definitely a step back in terms of off road performance, but it is orders of magnitude better on road than the 80. A SAS would fix the shortcomings off road and make it the perfect rig for us. I hope that doesn't sound like I just came into the 80 forum to talk s*** about the 80. Both trucks have their purpose.

 

[Broski]

JMHO
But you well lose some of what you like about the tree when you do the SAS it just wont be the same ride/handling

 

[mudgudgeon]

the tree

Cracks me up every time i read it

 

[mudgudgeon]

but it is orders of magnitude better on road than the 80. A SAS would fix the shortcomings off road and make it the magnitudes worse on road

Fixt

 

[Dindu Nuffin]

Cracks me up every time i read it

I get tired of typing Sequoia over and over.

Fixt

That may very well be. I’m being realistic and keeping in mind a solid axle will never drive as nice as ifs on the road. But what I keep coming back to is how well behaved the 80s I’ve had were on road. Everything’s going to be a compromise, and I accept that I’m going to have to trade some road manners for better off road durability.

 

[SNLC]

Tree?

Doesn’t the Sequoia not have a real transfer case?

I am ignorant, I know Land Cruisers.

Cheers

 

[Marvelicious]

If it were me, I wouldn't get too attached to the 80 axle. They're great, don't get me wrong, but with your stock rear setup being 66", you're basically right in line with older full-size axles. I get wanting to stay Toyota, but if I were going to this much effort, I'd do a 9.5" center with 80 outers (might as well, you've got to swap everything around for driver's side drop anyway), but it seems a lot simpler to just drop in some tons.

As far as the suspension goes, look at it this way: the manners of the radius arm setup are pretty good when everything is right, but you're changing everything anyway. I know it seems like it all should be easier because you're going with an existing setup, but by the time you shuffle everything around to make it work, you don't really have the same setup anymore. There's a reason guys go for leaf springs on solid axle swaps: it's usually easy to get them close enough to more or less work - not saying that's the way to go, just why people do. Personally, I'd go 3-link and coilover, rather than fight to reinvent the wheel with radius arms. Spring rates and sizes are going to be completely up in the air... You're mixing and matching two totally different rigs, so a 4" lift spring for one is most likely completely unlike a 4" lift spring in the other because it's mounted in different ways and has different forces working on it. Not just different weight, but the forces on an independent spring are totally different from the forces on a solid axle spring, but if you widen the solid axle out to match your rear, you're changing the forces again. And all that is to say nothing of the shocks. That's why I'm saying coilovers - it'll probably take some tweaking to get right, and it's a lot easier to do that with a set of coilovers.

I assume the Tree has the same rack and pinion steering that the Tundra has? You'll definitely need to address that. You're going to have to address brakes. Gearing potentially...

I'm not trying to rain on your parade... I'd love to a SAS on a Sequoia or Tundra that doesn't just treat it like an oversized Hilux and slap some leafs under it, I just don't want to see you bite off more than you're prepared to chew. Especially since it sounds like you want this to be a family overlander/wheeler. Getting it close enough to go mess around on trails with some buddies is one thing, getting it close enough to load your family in to cruise down the freeway safely, THEN hit the trails... well, that's a taller order.

Of course, it all depends on what you see when you crawl down under both rigs with a tape-measure. Sometimes things line up really well, but often they don't!

 

[Squeegee]

In my opinion, this is a lot of work for medium gains. Especially if you’re swapping an 80 axle to driver drop.
Im sure you know that the radius arms on an 80 are great when it’s not lifted, they do have a lot of antiroll characteristics which is cool, but they’re not worth copying with a swap, especially if you’re looking to lift it. They don’t flex well, the caster changes throughout travel which is “fine”. But do you want “fine” when you’re swapping an axle? Idk

You’re probably ganna want to cut off the brackets on the axle to clock it anyway or else you’re using $1000 radius arms or cheesey caster plates which is kinda dumb if you’re swapping an axle.

The center of gravity/ weight distribution and the rear geometry of the sequoia are different than an 80 so who knows how it’ll drive compared to a Land Cruiser. Maybe good, maybe fine, maybe bad… idk especially if the arms are at a steep angle.

In my opinions 80 axles aren’t worth swapping unless they’re going on a samurai or a 4runner/ pickup. They’re great axles, but there’s far more robust options that are far easier to find and far easier to swap.

If you’re committed to a hp 8” and 30 spline birfs, I would at least look into doing a ruffstuff radius arm kit or copy superduty radius arms. Lengthening the arms and keeping them flat should keep the drivability fairly tame with a bunch of sprung weight up top.

I’m sure this isn’t what you want to hear, but you’re in for a lot of work if you want to have the end result be good.

 

[Dindu Nuffin]

Parade not rained on at all, fellas. I came here for a reality check. If I wanted confirmation bias, I'd just talk to myself. I really appreciate the replies and it is making me reconsider the 80 axle. One thing nobody has mentioned when talking about front axle strength... is the Sequoia rear end. It's just a slightly wider semi floater Taco axle. Same 8.4" two spider gear diff, same diameter axle shafts but linked and with discs. That will be addressed down the road but will probably involve full floater chunks as it's already geared and Harroped.

Tree?

Doesn’t the Sequoia not have a real transfer case?

I am ignorant, I know Land Cruisers.

Cheers

Everyone's definition of real is different, so I'll just lay it out and let you decide if it's real or fake. It's a chain drive. With that out of the way and if you're still reading, there's two different generations of t-case in the 1st gen tree: 01-04, and 05-07. I have an '06, so I'll talk about that generation first. It has a Torsen center diff (not viscous like the FZJ), and a center diff lock switch from the factory. It also has the capability to be a true 2WD case with no power going to the front end. The axles disconnect at the diff so they're still spinning, but the front diff and driveshaft don't turn when in 2WD. AWD can be engaged at up to 60 MPH, and I think there might be a speed limit on locking the center diff, but I haven't bothered to look for it. The Torsen and A-TRAC still get the power to the front when the center diff is open and hitting the Harrop pretty much eliminates the need to lock the center diff, or at least for the stuff I do. A lot of purists gripe about it being an electronic case, but... eh... I kinda like the center console space without having a t-case lever there. The column shifter is the cherry on the top of that sundae. The '01-'04 Sequoias have a manual t-case with an open diff, but otherwise function the same as the '05-'07. I don't think the Tundra t-case has a center diff. As for the 2nd gen Tundras and Sequoias, I have no idea what's in them. Pickups don't really do it for me and the 2nd gen Sequoias feel unnecessarily gigantic while not having that much more interior room than the 1st gens. Also, IRS, but there's plenty of guys lifting them and running 35's, so they're not entirely helpless, I guess.

To tie the t-case in with my SAS, I'd considered swapping over a 100 series t-case for the passenger drop, but I'd need to find a way to add a shift lever and would also have to deal with a rear axle swap as well.

The 1st gen trees are by no means hardcore off roaders, but they're definitely hidden gems especially when clean unmodded ones go for half to one third of what a 100 goes for. Here's an example of one with a home made long travel front end on 37's getting some work done. Be sure to spot his license plate.

 

[AgentOrange]

So I'll jump in here as I have an 80 and a 1st gen Sequoia that I've looked at dropping my axle housing into when it comes out. 1" wheel spacers are needed to match the track width, but then the scrub radius isn't ideal. Not terribly worried about that. But to run the 80 front housing the other way is not a win. The real solution would be to run a 91/92 rear housing up front with 80 balls. That gets you a Toyota axle housing with the correct offset and a proper caster angle, 9.5 differential, which for the little V8 is a good idea, the larger 80 series birfields and off the shelf axle shafts, and then link it. That said, that's a ton of work and money that I'd rather dump into a long travel kit, RCVs and tires. My wife's Seqouia is running Rubicon next year and it's just locked front and rear with gears and armor. Adding 35s, sliders and sending it behind my 80. I enjoy it for what it is: a big family SUV that can party a little when the time comes

 

[Broski]

But to run the 80 front housing the other way is not a win. The real solution would be to run a 91/92 rear housing up front with 80 balls. That gets you a Toyota axle housing with the correct offset and a proper caster angle, 9.5 differential, which for the little V8 is a good idea, the larger 80 series birfields and off the shelf axle shafts, and then link it.

Already been suggested a couple of times

 

[cruzinfj1]

RuffStuff 9.5" housing with 80 knuckle balls. Cut it whatever length you need and then make it a d/s drop..... can also set your caster.

 

[Dindu Nuffin]

So if I used a rear housing, what diff would I use? The rear diff?