4Link Suspension

[Tigerstripe40]

I am looking at different suspension options for my FJ40.

One of them is a 4 link.
There are 4 link suspensions available for Jeep Wranglers that allow for extremely flexible suspensions, yet still retain street driveability.

I don't have the option to tow my Land Cruiser.
End of story.

However, I would like to have an extremely flexible suspension.
Why is a 4Link not suitable for road use?

Is it due to the lack of sway bars?

Or should I just do a SOA?
I want to run 37" tires. Be able to wheel the HELL out of my rig, and still be able to drive it to the trail.

 

[Mace]

how good are you at fabwork..


Actually, from they way your questions is worded.. Just do the SO.

There have been a bunch of threads on how to make a linked suspension behave on the street. What it all boils down to is one thing. Do your research. Asking questions will net you about 56 billion replies that are different. None of which are perfect for what you want.

 

[Isotel]

Properly Designed 4 link can be fine on the street (Examples being all the TJ's you see)

Swaybars will obviously make the truck more streetable, Same with sways on a Spring Over..

Spring over is a good place to start, then maybe link the rear if your not happy with the flex..

Last time i went to moab i got passed by a guy in a Jeep CJ with 1/4 Eliptical Rear / 4 link.. He was on I-70 doing about 70mph, so it can and has been done before.. Like Mace said, do your research, there is about 10,000 different ways to do a 4 link!

 

[LC_Hamma]

Ya gotta have the KNOWLEDGE, PROPER TOOLS, $$$ & TIME to tackle a 4 link. I studied many different setups & decided to fab mine similar to a TJ/ YJ & skid plate idea from the old Warn XCL kit. If I had to do it again, I'd make the lower link mounts seperate from the skid & try to have a parallel track bar but I was really limited to space. Here's a general price figure I went from:

4" Ebay TJ coils - $120.00
used TJ coil buckets front & rear top & bottom from Pirate Wanted Section - $90.00 I didn't use the front uppers
4 lengthened Explorer Procomp shocks $130.00
12 - 3/4" cromo rod ends steering & track bar included - $32.00 each
6 - Flex Joints builder ball assy. - $48.00 each
tool for Flex Joints - $22.00
1 3/4" 1/4" wall DOM - you get your local price I sleeved the rear lowers w/ 1/8" wall
1 1/2" 1/4" wall DOM for draglink & tierod - get your local price
misc. steel & hardware - get your local price
driveshafts - used same front/ rear used a CV $250.00
optional front & rear wheel spacers not needed but I used them - forgot price
This is all based on a y-link front & 4 link rear setup running 38" tires.

You can check out pics of my '73 FJ40 below. PM me if you have any questions.

 

[Eskimo]

I've driven a bunch of TJ's that were linked, and frankly, my SOA FJ with the 101" WB was FAR more stable... freakin TJ's rocked sideways everytime they hit the gas...

Mainly, many of the custom 4-link designs trade street maners for off-road performance (like a high roll center).. BUT, as long as you realize your reduced performance on the street and respect it, you should be OK. As was mentioned, sway bars help alot, too.

IMO, a longer wheelbase helps alot..
Just my $.02

Oh, and don't let Nolen take you for a high-speed run in the bash buggy.. you'll never feel safe again..

 

[Tigerstripe40]

I am playing with the 4 link calculator.
Figured I would throw my numbers out.
I figure on running 37" tires.
And the truck weighing it at 4200 lbs.


Lowers made from 2.5" DOM with a 3/8" wall.
Probably just use XJ bushings.
they are 55" long

Uppers from 1.5" DOM with 1/4" wall.
38.5" long

looking at 88% antisquat.
A RC slope of 0.0020
RC height of 27.5"
RC angle if 0.1195 degrees.

I can fiddle with it to get the RC slope to zero.

How does that look

 

[CRUZR66]

No Trailer Queen, 4 Link Suspension

Hi, I did my own 4-Link 4 years ago, I drive to and from the Rubicon to the SF Bay Area, No Trailer queen Here, Ask a Lot Of Questoins, I have Coil springs in therear with the fourlink, Coilovershocks would be Better, I get a lot of Body roll, I have limiting straps, here's a few web sites to check out:


AlaskaOffroad, Spidertrax Offroad,(theyre a samuri setup)



I'll try to find some more of the Refrences i've used, If you do it Right it, the Four Link will work as weel as the stock spring set-up,

My Lower Links(Arms) are Parellel to the Frame and Stock Spring Mounts, The Upper Links Form a V from the sides of the frame near the Transfere Case back to the Top of the Rear Axle, I used 3/4" Hiem Joints, use Hiems and Some JonnyJoints or Rebuildable Joints on the Other ends, please feel free to contact me if anyother Info needed

CRUZR66

 

[Eskimo]

55" long links? where are they gonna mount - the bell housing? Also, I'm not sure if you can use 2.5" tubing on XJ bushings.. 2" might be about it IIRC.

The numbers look good assuming everything else is correct, but I'd work in some adjustability into maybe the frame side upper mounts, since numbers are just that...

 

[Mace]

coilovers do not help with body roll. Sway bars do. 55" long lowers are huge.. I mean dam..

even 2.5" tube with 3/8" tubing will bend at that length

 

[DHONDAGOD]

My lowers are 56" long and they dont bend.......




























'course they ARE .500" thick 2" diameter chromoly.....



Chris

 

[Tigerstripe40]

coilovers do not help with body roll. Sway bars do. 55" long lowers are huge.. I mean dam..

I said I wanted a long arm suspension.

 

[outbackoffroadgear]

We are putting a long arm kit together for the fj40 right know.Kit will be available soon for resale.