Double triangulated rear 80

[nukegoat]

Both if you don't mind, but particularly up on the frame

I'll see what I can procure

 

[nukegoat]

Not great cell shots but here you go

 

[jcardona1]

Not great cell shots but here you go

Thanks, that does help. I'm more motivated to work on the rear suspension now and after doing the front this seems like a piece of cake. Here's what I'm thinking of doing. I'd like your feedback if you don't mind since you've done the research on this.

• For the lowers, I plan on copying what you did although I still can't visualize how the heck you fit a crossmember under the gas tank and the links don't ever hit the gas tank.
  
  
• For the uppers, thinking of doing a full double triangulated 4 link. Cutting off the towers at the axle and using the RuffStuff truss. Looks like it would fit in between the coils, might need a tiny bit of trimming
  
  
  
  
  
  
• With a horizontal link bracket like this:
  
  
  
  
  
  
• - So my questions: Do you think this upper configuration would work with the OEM frame uppers? Is that enough triangulation? I realize I'll probably need some sort of flex joint instead of bushings...or can I get away with using bushings at the upper frame mounts? Or is a wishbone a better choice if using the OEM frame upper mounts?
  
  
• Anything else to keep in mind?
  
  
• Thanks!

 

[nukegoat]

Thanks, that does help. I'm more motivated to work on the rear suspension now and after doing the front this seems like a piece of cake. Here's what I'm thinking of doing. I'd like your feedback if you don't mind since you've done the research on this.

• For the lowers, I plan on copying what you did although I still can't visualize how the heck you fit a crossmember under the gas tank and the links don't ever hit the gas tank.
  
  
• For the uppers, thinking of doing a full double triangulated 4 link. Cutting off the towers at the axle and using the RuffStuff truss. Looks like it would fit in between the coils, might need a tiny bit of trimming
  
  
• - So my questions: Do you think this upper configuration would work with the OEM frame uppers? Is that enough triangulation? I realize I'll probably need some sort of flex joint instead of bushings...or can I get away with using bushings at the upper frame mounts? Or is a wishbone a better choice if using the OEM frame upper mounts?
  
  
• Anything else to keep in mind?
  
  
• Thanks!

I don't want to discourage you from doing the rear at all but you're venturing into suspension design theory - as a plug for what you did to the front, that was great because you bought a package, welded it on, and the geometry was figured out by someone else. This isn't just a "it'll fit there" sort of exercise - you have to know what the consequences of your design are. And roll axis isn't the end-all concern... there's squat, instant center, roll height, etc.

Packaging the lowers is a challenge due to the gas tank but, as I said, I made it work. I am running 36's so the tire is fully stuffed before the link smashes the tank. The lowers are your biggest challenge to a good roll axis - if you don't want them hanging way below the frame, you have to either raise them at the axle (hard to do, though I did a little bit) or triangulate them inboard at the frame (which requires a crossmember). Plan on losing your factory muffler if you havent' already.

The uppers on the axle are the easiest part. The only thing to keep in mind is that the distance from the factory crossmember is miniscule so to make it work, you'll want to bring it back as far as you can without it looking goofy (mine sits a few inches behind the center line of the axle).

Running a wishbone means that there is only 1 axis of rotation to worry about. If you want to run a double triangulated, you'll have to trim the factory bracket to allow the link to clear as it rotates about (and is laterally displaced). This is a weird advantage of wishbones upper links, btw, but I took advantage of it. Frankly, I wouldn't ordinarily recommend a wishbone design as it is a more difficult thing to design but it suits this situation well.

The other thing to bear in mind is how your pinion angle changes through travel. I feel like I stumbled on a very good conclusion with my design - it can flex all around while maintaining a somewhat healthy pinion angle.

 

[jcardona1]

I don't want to discourage you from doing the rear at all but you're venturing into suspension design theory - as a plug for what you did to the front, that was great because you bought a package, welded it on, and the geometry was figured out by someone else. This isn't just a "it'll fit there" sort of exercise - you have to know what the consequences of your design are. And roll axis isn't the end-all concern... there's squat, instant center, roll height, etc.

Packaging the lowers is a challenge due to the gas tank but, as I said, I made it work. I am running 36's so the tire is fully stuffed before the link smashes the tank. The lowers are your biggest challenge to a good roll axis - if you don't want them hanging way below the frame, you have to either raise them at the axle (hard to do, though I did a little bit) or triangulate them inboard at the frame (which requires a crossmember). Plan on losing your factory muffler if you havent' already.

The uppers on the axle are the easiest part. The only thing to keep in mind is that the distance from the factory crossmember is miniscule so to make it work, you'll want to bring it back as far as you can without it looking goofy (mine sits a few inches behind the center line of the axle).

Running a wishbone means that there is only 1 axis of rotation to worry about. If you want to run a double triangulated, you'll have to trim the factory bracket to allow the link to clear as it rotates about (and is laterally displaced). This is a weird advantage of wishbones upper links, btw, but I took advantage of it. Frankly, I wouldn't ordinarily recommend a wishbone design as it is a more difficult thing to design but it suits this situation well.

The other thing to bear in mind is how your pinion angle changes through travel. I feel like I stumbled on a very good conclusion with my design - it can flex all around while maintaining a somewhat healthy pinion angle.

Thanks for the help. And you're right. The only reason I'm considering doing this is because you've done it and shown it can work. Otherwise I don't think I could bring myself to start cutting and welding up links where ever they land. That gas tank really is a pain in the ass. Everything would be so much easier without it in the way, but definitely don't want to venture into fuel cell territory.

So what's the deal with these reverse single triangulated 4 link setups I've seen on Jeeps. What does that to geometry and road manners? Seems like departure angle might suffer too

With that said, if I decide to do this, I'll try to mimic your setup as much as possible since we have close to the same lift and tire size. Re: exhaust, my stock exhaust is gone. I do have a Flowmaster muffler hanging up near the TC so that would have to get moved. First order of business is a rocker chop and I also want to pivot the cats. If I can find a muffler that'll fit right behind the cats with a straight shot out in front of the rear tire I'll go that route. This isn't a DD so I'm not that concerned with noise and cabin drone.

With the exhaust out of the way I can take my time farting around with a crossmember and fab one that fits. You used 3x3 3/16" wall right? For the uppers, I'm thinking of the RuffStuff truss like I mentioned, cutting off the factory axle mounts. I see RuffStuff sells a horizontal wishbone bracket which should make it easy.

Got a link to the uniball piece you used to attach the uppers to your truss? Basically something like this right?

Lowers at the axle: So I got to thinking. Our stock coil buckets are in issue if you want to raise the lowers at the axle. Since I'm doing all that work, why not cut it all out and get an integrated coil bucket/link mount like this one? No reason it wouldn't work right? Clean up the axle and raise the lowers at the same time.

Then I looked at the lower shock mounts. Freaking boat anchors. I have shock protectors on but even those are getting quickly destroyed. One of the pin mounts is also bent. Don't see it holding up much longer. So why not cut that entire thing off and raise it up a bit with these new mounts? Still mounts below the axle center line but without giant bracket hanging down low. Or if these aren't good enough I could always use some universal shock brackets. This is all assuming moving the shock up won't mess with my up travel.

So how stupid is this whole idea? It's just money right?

 

[SNLC]

Thanks for the help. And you're right. The only reason I'm considering doing this is because you've done it and shown it can work. Otherwise I don't think I could bring myself to start cutting and welding up links where ever they land. That gas tank really is a pain in the ass. Everything would be so much easier without it in the way, but definitely don't want to venture into fuel cell territory.




So how stupid is this whole idea? It's just money right?

I see no reason you can't use the RS coil buckets. I am using them on a front axle build, also using a RS housing.

Moving shock mounts up will mess with your up travel. If you move the axle mount up you need to also move up the frame mount. Can't do that without cutting up the body. Look at a Nissan Patrol rear axle, almost the same as the 80 except the RLCA are outboarded on the frame. Shocks are mounted behind the axle. That is what you really need to do or look into doing. Due to how the 80 is designed though not super easy to do that.

If you don't care about money, run 7075 RLCA links with JJ's. I have 7075 2" links under one of my trucks. Extremely tough. I have a video of the truck on Pritchett Canyon and the RLCA takes all the weight of the truck up a ledge. You can see the link bend and then spring back into place. IMHO, these are the best links you can get.

Cheers

 

[nukegoat]

Thanks for the help. And you're right. The only reason I'm considering doing this is because you've done it and shown it can work. Otherwise I don't think I could bring myself to start cutting and welding up links where ever they land. That gas tank really is a pain in the ass. Everything would be so much easier without it in the way, but definitely don't want to venture into fuel cell territory.

So what's the deal with these reverse single triangulated 4 link setups I've seen on Jeeps. What does that to geometry and road manners? Seems like departure angle might suffer too

They are weird. Theoretically they could be done correctly within a range of travel. In practice, probably not. Don't bother.

With that said, if I decide to do this, I'll try to mimic your setup as much as possible since we have close to the same lift and tire size. Re: exhaust, my stock exhaust is gone. I do have a Flowmaster muffler hanging up near the TC so that would have to get moved. First order of business is a rocker chop and I also want to pivot the cats. If I can find a muffler that'll fit right behind the cats with a straight shot out in front of the rear tire I'll go that route. This isn't a DD so I'm not that concerned with noise and cabin drone.

With the exhaust out of the way I can take my time farting around with a crossmember and fab one that fits. You used 3x3 3/16" wall right? For the uppers, I'm thinking of the RuffStuff truss like I mentioned, cutting off the factory axle mounts. I see RuffStuff sells a horizontal wishbone bracket which should make it easy.

Definitely orient the uniball vertically - based on the loads it takes it's not wise to do otherwise. The bracket you pasted does that, so that's good.

Got a link to the uniball piece you used to attach the uppers to your truss? Basically something like this right?

I used the poly performance one. Like a hundred bucks. I think that's what your pic is.

Lowers at the axle: So I got to thinking. Our stock coil buckets are in issue if you want to raise the lowers at the axle. Since I'm doing all that work, why not cut it all out and get an integrated coil bucket/link mount like this one? No reason it wouldn't work right? Clean up the axle and raise the lowers at the same time.

Then I looked at the lower shock mounts. Freaking boat anchors. I have shock protectors on but even those are getting quickly destroyed. One of the pin mounts is also bent. Don't see it holding up much longer. So why not cut that entire thing off and raise it up a bit with these new mounts? Still mounts below the axle center line but without giant bracket hanging down low. Or if these aren't good enough I could always use some universal shock brackets. This is all assuming moving the shock up won't mess with my up travel.


So how stupid is this whole idea? It's just money right?

Using a new coil/lower mount combination thingamajig is great, sure, but you will be likely interfering with your gas tank. I think you're approaching this the wrong way - it seems you're trying to identify what off-the-shelf brackets you can buy first rather than approaching it from an engineering / geometry standpoint. Think of it this way: what CANT move? what are your constraints? For the lowers, this is going to be your frame mounts. For clearance reasons, you probably want them relatively tucked, but also inboarded as much as is reasonable to improve your roll axis (I wouldn't cross under the driveshaft, though). Then, based on that, figure out your maximum "bump" or stuff condition. You can then draw a straight line from the lower mount to the axle. Too low and you'll have a worse roll axis / worse ground clearance. Too high and you'll be stuffing it into your gas tank. Anecdotally, mine only moved up about an inch. I think the bracket you showed would be too high. Then your uppers... figure out how high off the axle it needs to be (and how far back) in order to get the proper behavior. Off the shelf brackets may not work at all here.

Shock mounts moving out of the way would be great but, although I damage mine, I don't think it's worth relocating them. Still, I just haven't given it much thought. I think my next project may be to go to coilovers in the rear mounted behind the axle and up through the cab. But I don't know yet.

 

[nukegoat]

I see no reason you can't use the RS coil buckets. I am using them on a front axle build, also using a RS housing.

Moving shock mounts up will mess with your up travel. If you move the axle mount up you need to also move up the frame mount. Can't do that without cutting up the body. Look at a Nissan Patrol rear axle, almost the same as the 80 except the RLCA are outboarded on the frame. Shocks are mounted behind the axle. That is what you really need to do or look into doing. Due to how the 80 is designed though not super easy to do that.

If you don't care about money, run 7075 RLCA links with JJ's. I have 7075 2" links under one of my trucks. Extremely tough. I have a video of the truck on Pritchett Canyon and the RLCA takes all the weight of the truck up a ledge. You can see the link bend and then spring back into place. IMHO, these are the best links you can get.

Cheers

+1 except I don't think johnny joints are the bees knees. Tapped 7075 is indeed nice but expensive. Not worth the weight savings on an 80, especially for experiments that may require a rev 2

 

[maxamillion2345]

I agree, I'd just stick to DOM links and knowing what I know now, 1.25 FK heims.

I'd go double shear mounts on the shocks.

Also, I got to see something interesting in person a month back, V crack they call it, watched probably 30 rigs try it. Lots of rigs walked it like it wasn't there. Watched some seriously built buggys and truggys and whatever fall in time after time after time after time. I mean struggle for 30 minutes and give up. They'd get their front and ass lined up right and they'd climb and as soon as that rear end flexed it'd start walking on them, and kick em into the hole. It was almost always a linked rear. Rigs on leaves seemed to walk it 1st try if they got lined up right. Some linked rigs walked it 1st try too if they didn't have crazy rear steer.

Was pretty interesting to watch happening. Not saying I could build a linked rear end that wouldn't have a lot of rear steer, but I saw where it could really bite you.

Also, if it really matters to you, with a 2" body lift and my lower shock mounts right on the centerline of the axle tube I was able to fit a 14" travel shock without inboarding them.

 

[Rivman1243]

@nukegoat Where can I learn about all of these suspension terms and theory. Is there a website you could recommend.

 

[baldilocks]

ibhaters, people bringing random criticism, defending toyota design, blah blah blah

Here's the before. 13 degrees of roll oversteer, low roll center height, tons of flex steer... this is w/ a 5" lift. Horrible. Still flexed ok but didn't work right on-road and was too wobbedy for my tastes. If you're running stock suspension, this is you:

I designed this so the only things that have to be welded on are two frame plates that a lower link crossmember bolts to and a couple of tabs on the axle to bring the axle lower links up (they weld to the oem lower plates for alignment. Oh, and a couple of triangulation gussets here and there for the heck of it.

That said, the truss could be fabbed on the bench, the wishbone could be fabbed on the bench, the links and frame crossmember are fabbed on the bench, and then it just bolts in all win-like.

Sleeve off-road

For you geometry weiners out there

How does it drive? Hopefully good. I don't have exhaust as you can see in the pics so I'll be taking it to a shop to replace the oem water heater with something that doesn't hang below the frame rails.

Nice bro!

 

[nukegoat]

@nukegoat Where can I learn about all of these suspension terms and theory. Is there a website you could recommend.

I mentioned some books in another post but just start with terminology and try to deeply understand each concept in whole... itll make more sense then

 

[maxamillion2345]

Front Suspension Technology Link Basics Part 2 - Off-Road Magazine

Look up other part as well

Then google

 

[jfmaillot]

Hi,
Just sharing... it works great off and on road, it's strong as it looks. I'm looking for my coil overs now... running radflo 2.5 for now. I just cut the panhard brackets this weekend. no pics yet (I'm at work lol)
regards
PS : made all with US parts

 

[nukegoat]

That is the correct bolt orientation

 

[jfmaillot]

That is the correct bolt orientation

indeed
this ruffstuff bracket is as strong as nails / trail gear beefy rod end / OEM bushings on the chassis
I've been rolling with this triangulation since 2012...

 

[nukegoat]

indeed
this ruffstuff bracket is as strong as nails / trail gear beefy rod end / OEM bushings on the chassis
I've been rolling with this triangulation since 2012...

Where were you earlier when i was trying to figure this out??? Lol

 

[Rivman1243]

Thanks for the direction

 

[jcardona1]

Hi,
Just sharing... it works great off and on road, it's strong as it looks. I'm looking for my coil overs now... running radflo 2.5 for now. I just cut the panhard brackets this weekend. no pics yet (I'm at work lol)
regards
PS : made all with US parts

View attachment 1330921

View attachment 1330923

17 posts in 8 years and you hit us with this, yeah gonna need a lot more pics Did you do anything with the lowers? Are you also using this horizontal bracket with a uniball joint? Horizontal Wishbone Bracket

 

[jfmaillot]

Sorry guys I'm a little slow. The site won't allow me to post more pics (wtf?)
Sorry for my English too... I'm French
Actually this rear build was very slow and this is the last upgrade
I'm using the horizontal wishbone bracket with a trail gear rod end (1") on the axle and oem silent blocs on the chassis. The oem brackets need to be trimmed. I tried to put the rod end vertical but I wasn't happy with it. I used the oem bracket as a support on the axles and bend some dom tube for strength. Then added some cool gussets from poly performance I think. I will add some gussets for strength and style too