Link Question (1 Viewer)

[Mr. Notorious]

Got the hard part of the project done, cut off all the bracketry off the 80 rear axle, assemble all the brakes, slight stretch, and pull out some misc from under the FJ. My question is, what are the positives and negatives of an asymmetric triangulated 4 link setup for the rear? Where basically the uppers aren't centered, but in this case, ontop of the slightly offset rear differential.

Also, anyone hook up a driveshaft from a 80 series rear to a 40 series t-case? Wondering if I'm going to need a double CV driveshaft since the 80 rear is a little offset differently than the 40...

 

[LT]

There are so many ways to do a 4 link. It really comes down to basically how you want to set it up and what fits best under the rig.

You can do it where the lowers are triangulated and the uppers are straight, dual triangulation, or the uppers triangulated with the lower straight or slightly pointed out. Start taking measurements of where stuff will fit and use the 4 link calculator to see what works best for your application.

 

[Mace]

if you put the apex of the links offset, the axle will piviot around them.

REALLY bizzare suspension under flex.. Drivers side will flex into the body. passenger will not flex as much..

I cannot think of a single positive..

 

[Mr. Notorious]

if you put the apex of the links offset, the axle will piviot around them.

REALLY bizzare suspension under flex.. Drivers side will flex into the body. passenger will not flex as much..

I cannot think of a single positive..

I thought it'd help prevent torque squat from my 350 having the short side on the passenger side where most triangulated 4 links squat. Is that a fair assumption?

Has anyone else done this?

 

[Isotel]

its the design of the links that will affect the Squat and roll characteristics of the rig.. put your idea into the 4 link calc and see what it tells you.. im pretty sure you will want to build a platform off of the 3rd in the center of the axle to mount the uppers..

 

[Mace]

I thought it'd help prevent torque squat from my 350 having the short side on the passenger side where most triangulated 4 links squat. Is that a fair assumption?

Has anyone else done this?

Bad assumption.. And actually, the "short" side of a V8? And why do you think that most 4 links squat to the passenger side???

Wait, do you know what antisquat is?

(not being rude, just want to know what level to take this to)

 

[Mr. Notorious]

Bad assumption.. And actually, the "short" side of a V8? And why do you think that most 4 links squat to the passenger side???

Wait, do you know what antisquat is?

(not being rude, just want to know what level to take this to)

I don't know the specifics, but I always see jeeps with triangulated 4 links (w/o trackbar) dip their right rear down and pick up the front left under acceleration. Can't say I've ever seen it the other way. Have you?

And yes, I know I'm not adjusting/adding uneven antisquat because I'm not moving the links up or down. And by saying short side, I referring to the passenger side having a shorter link than the driver side. Never said anything about short side of a V8

But nevermind, sorry for asking. I'll just try it out. I figured it wouldn't articulate too weird with only running a 10" travel shock in the rear. Anyways, I know Rover defenders were setup like this, couldn't have been that bad of an idea.

 

[Mace]

What you have seen is a reaction to the rotation of the motor.. Not the links.. A slightly stiffer spring on the DS would solve the issue. But honestly, you are chasing a ghost..

If you actually manage to design the torque twist out of the truck you will actually end up having a "stiffer" ride on the passenger side.


Up to you if you want to try it.

Panhard bar, not a trac bar.. significantly different things..

Personaly, I would not worry about it.

 

[Eskimo]

Driveshafts don't care if they are angled to the side, or down. angle is angle.

And like Mace said, center the links.

 

[Mr. Notorious]

Probably should have updated you guys awhile ago... Been on it's feet for almost 2 weeks and I've been driving it ever since . I decided to go ahead and try it. If it doesn't work, I'll try something else.

Everything's tucked up nice and outta of the way. I also opted to mount the procomp MX6's up and out of the way of rocks.

Even bent up the lowers for better ground clearance....

Since these pictures, don't worry I've trimmed out the extra sheetmetal from the backside of the flare, installed the shocks, cleaned up some misc wires outta the way, ran all new brakelines, and I'm working on getting a driveshaft made. Locals guys didn't want to be bothered with a double CV shaft. Which in one respecte I was pleased with since they went crosseyed when I tried to explain my compound angle issue. They couldn't seem to picture it, let alone answer my question if a u-joint is more prone to dislike a compound angle. Then when I asked if they'd like to come out to the parking lot to see my situation they said they couldn't for insurance reasons.

Even though the flares are from a TJ, they tend to blend in the 6-7" stretch fairly nice. Not to mention, they almost match the lines of the front fender.

 

[BiffS]

Dude. . .

your upper rear links at the frame end are not going to like that much misalignment for long. I would guess that they'll wear quite fast or produce some odd binding at full up or down travel. solution is to rotate 90 degrees.


another big consideration is that as Mace said basically your thrust angle will be all wacky: the centered part of the imaginary triangle that the links produce will be where the rear thrust force will be centered from. when under different loads or articulated positions, they'll offset the axle at uneven points with different rear-stear amounts (as the axle cycles through it's positions)

hitting a whoop-de-do under hard acceleration could be tragic.

on the driveshaft note: the shaft doesn't care if it's up, down sideways or whatever. angle is angle.

my 40 with a 60 series axle runs the DS slightly off center. you could look for a used 60 series front drive shaft to get a CV shaft for your truck for cheap too.

this photo is my front but you get the idea (rear the same)
been running this truck like this for 3 years: only get rear steer (2.5 degrees) at maximum articulation on 18" air shox. I'm going to re-do it this winter to try and get it as close as possible to zero.

 

[Mr. Notorious]

Yeah I hear ya about the frame mounted upper joint. It's actually at neutral on level ground and I'm only running a 8" travel shock. I'll see how it goes, the joints are completly rebuildable so wearing doesn't really concern me (rebuild kits are like $5 a joint)... If I feel like going big down the road it'll most likely go to an independent 3 link.

 

[peesalot]

More pics of the link mounts up close, I really dig your link job. Nicely done.
Could you post the lengths of the links as well.

 

[Mr. Notorious]

Looking for frame mount pics?

I think my arms are around 33"s...

 

[lowtideride]

Maybe I am missing something, but dont you need a pan-hard if you are not running triangulated uppers and lowers???

Looks like nice fab work, just wondering if it works right...

 

[Mace]

as long as one set of links are triangulated, no panhard is needed..


Think Wishbone 3 link..

 

[lowtideride]

as long as one set of links are triangulated, no panhard is needed..


Think Wishbone 3 link..

Huh, dint know that. I always thought they both had to be. I guess I can add that to the long list of other things I don't know

 

[Mace]

Huh, dint know that. I always thought they both had to be. I guess I can add that to the long list of other things I don't know

Not any more

 

[Mace]

I will add tho.. There needs to be a reasonable amount of triangulation in those 2 links for it to work. If the triangulation is very shallow, a panhard bar is still needed..

 

[BiffS]

More pics of the link mounts up close, I really dig your link job. Nicely done.
Could you post the lengths of the links as well.

Mine or his?