3 link vs. 4 link (1 Viewer)

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Or maybe more appropriately; 3-link+panhard (4-link?) vs. 4-link+panhard (5-link?).

I see a lot of threads on people doing 3 links and that's awesome!

But why no 4 links? They flex better than our stock setups and IMO are probably safer due to the redundancy of the 2nd upper link.

Not trying to start a war here. 3 links are cool. I'm just surprised at the lack of custom 4 links fabbed into 80's. Maybe I'm just missing them??
 

nukegoat

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I have the 5-link design on the front of my 80. It flexes well enough but you are constrained in the design to make sure you don't change caster angle much as it travels (otherwise you bind and you're back to limiting flex again). It's fine for the sort of travel I'm getting out of the shocks I have, but you can't beat a 3-link for total overall flex and freedom of design.

That said, the 5-link has more predictable behavior under acceleration and braking since there's better symmetry to the design. It's also arguably slightly safer since you can lose a link and the system still works. Lastly, it's trivial, but you don't need as much link separation at the axle since the forces are distributed between two upper links instead of one... so if you have vertical packaging constraints (we really don't on the 80, but if you did....) then it may be preferable.

If I had to do it over again, I'd probably go with a 3-link since it's a bit simpler to design and I could engineer caster change as the suspension cycles - desirable for the CV joint I run at the xfer case.
 

nukegoat

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BTW, I also designed my setup to retain the factory anti-roll bar, which ends up being a waste of time and effort because it's too undersized to really drastically improve road manners, but stiff enough that you want to remove it at the trailhead (and it's not exactly pleasant to remove and re-install all the time). My experience with that was why I re-iterate to people over and over that they don't realize how much the front radius arms act as a giant anti-roll bar in the 80 - they can run around with horrible roll axis' because the amount of roll-induced oversteer is minimal when you have very little overall suspension articulation to worry about.
 
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I agree that a 3 link would flex more than a 5 link (good to keep common terms here). I'm also sure that a 5 link flexes significantly more than the factory setup, which makes me think it's probably good enough for those of us looking for more than the factory setup offers, but still daily drive our 80's a large majority of the time and want that safety factor.

I hear you on the factory anti-sway bar vs. radius arm setup.

You have a build thread? I'd like to see your setup.
 

nukegoat

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I agree that a 3 link would flex more than a 5 link (good to keep common terms here). I'm also sure that a 5 link flexes significantly more than the factory setup, which makes me think it's probably good enough for those of us looking for more than the factory setup offers, but still daily drive our 80's a large majority of the time and want that safety factor.

I hear you on the factory anti-sway bar vs. radius arm setup.

You have a build thread? I'd like to see your setup.

Eat your heart out

https://forum.ih8mud.com/threads/1995-fzj80-aka-marshmallow-4-link-front-5-lift-36-km2s.768168/
https://forum.ih8mud.com/threads/wheelin-the-hammers-johnson-valley-in-marshmallow.799019/
 
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I'll point out you can't buy a link kit from the many reputable vendors(artec, Barnes, ruff stuff, 4wu) with 5 links in it. Front or rear.

They aren't sold with a 5th link for a reason. We can discuss it, but well probably argue:D
 

nukegoat

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I'll point out you can't buy a link kit from the many reputable vendors(artec, Barnes, ruff stuff, 4wu) with 5 links in it. Front or rear.

They aren't sold with a 5th link for a reason. We can discuss it, but well probably argue:D

Yes, but there are also more dysfunctional lift "kits" than functional ones, so the existence of a market for something doesnt' mean it's technically the right solution. The relative lack of link kits for the 80 wasn't because radius arms were superior, right?

Anyway, that's not even precisely true (that no reputable vendor sells a 5-link kit) There are plenty of Jeep kits and OEM designs (including the rear linkage for the fzj80, and 4runners since 1990) that use 5 links. I am not suggesting people bother trying to engineer one since they are significantly more complicated to get right, and I think for most people the pros are not worth the hassle, but they do work.
 

nukegoat

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Good enough? If you go through all the headache of linking your junk are you really shooting for good enough?

Well, to be fair, didn't you just "good enough" it and throw leafs under the rear of your 80? Not knocking it, but engineering and design is a series of compromises - sometimes just in terms of money, complexity, and cost.... but other times there are packaging and performance considerations that people weigh. He said it would flex "good enough" for people, and I agree with that sentiment if done correctly.

Ultimately, we can agree that bad design and bad implementation will be worse than a good design and good implementation of any another suspension design. In the real world, there are more factors to consider than just the number of links. So, to make a fair comparison, we have to hold all other things constant. In this case, I think the main reason to go with a 3-link is freedom of design and simplicity. Within the range of motion that anyone on this board cares about, you can design a 5-link to flex equivalently, but it may come at the expense of other design constraints (as I discovered). There are benefits to a 5-link as well, but those are inframarginal for the 80 platform, IMO.
 

maxamillion2345

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Well, to be fair, didn't you just "good enough" it and throw leafs under the rear of your 80? Not knocking it, but engineering and design is a series of compromises - sometimes just in terms of money, complexity, and cost.... but other times there are packaging and performance considerations that people weigh. He said it would flex "good enough" for people, and I agree with that sentiment if done correctly.

Ultimately, we can agree that bad design and bad implementation will be worse than a good design and good implementation of any another suspension design. In the real world, there are more factors to consider than just the number of links. So, to make a fair comparison, we have to hold all other things constant. In this case, I think the main reason to go with a 3-link is freedom of design and simplicity. Within the range of motion that anyone on this board cares about, you can design a 5-link to flex equivalently, but it may come at the expense of other design constraints (as I discovered). There are benefits to a 5-link as well, but those are inframarginal for the 80 platform, IMO.


Better than stock :hillbilly: and compliments the front well too. Yeah I could have dual triangulated 4 linked and I could down the road too but theres constraints to interior space there as well to do it right IMO. Or opposing panhard rear 3 link but again I think it's an issue of space. As well as money. To me the front is more of a concern. Chevy 63s will be more stable, and flex more than the stock rear. Anyhow I know leaves are somesort of heathenisitc blaspheming ancient technology around here but I think I'll like em. They're also really simple to set up so it's not quite like going through the hassle of linking something but I know what you're getting at.

But as for the 3 link, I think you're right. Packaging certainly becomes an issue, or it would be with my 6bt anyway. Even dual triangulated (I don't want full hydro anyway).
 

Tapage

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Main concern for a 4 link over 3 it's just more predictable stable behavior under braking .. not binding it's an important issue when panic braking in a heavy rig like our 80 ..
 

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