Front 3-Link Setup

[RuffedUpXJ]

I have had horrible short arms on my XJ for 5 years or so now and I am in the process of swapping all of my aftermarket parts over to a nice, clean and straight XJ. I have looked into 3-links before and understand the majority of it. Most people say 5-7in of separation at the frame and 8-10 at the axle and just make whatever you can fit. So that's all good and I can definitely make that happen but with the 3-Link calculator there are some number I don't understand completely and also I don't know what to shoot for.

Have any of you figured these numbers out?

Anti-squat? Shoot for 100% since there is that line on the graph?

Roll axis angle? I know on the rear it will steer the rig one way or the other but the front end most people say it's not as big of a deal. Shoot for 0 degrees I assume.

Roll height center? I know that has to do with track bar placement and doesn't seem to effect anything else. So not sure of a number to shoot for there.

Here is a rough version of what I think I can do on the front end of the XJ.



Also there is always a big debate on what joints to run and where to run them. I think right now I am doing 3/4 hiems on the upper link and I have some 1.25" hiems for the lower but not sure if rubber bushings would last. The XJ does a lot of road because I drive it to and from but also, tow the boat and other trailers around.

[yellowjacket]

Forget about antisqat. That only has to do with the rear. In the front its called antidive. If u was settiing up the rear u would worry bout antisqat. And thats up to personal preference anyway, along with your intended use. A moot point for u though.

[itbrokeagain]

Why not Y link it?

[RuffedUpXJ]

Well Y link has the tendency, I have heard, to unload on hill climbs and not have as good road manners as a 3 link. It's the all the rage in the XJ world, just kidding. It seems to be working out well for a lot of people. Seems to out perform the Y link since majority of the 4x4 companies are now making 3 links vs Y links.

[sarge]

I'm in the same boat with My Jimmy. I think I'm going to run 7/8th Hiems on the upper and 1 1/4 lowers at the frame and use rubber bushing at the axle. I'm doing this because it see the road as much as possible and it's not a tube buggy with massive amounts of flex . Heims all the way around is cool but I think unneeded on a full bodied vehicle IMHO . thoughts???

[flatlander757]

I had a HUGE reply typed up explaining everything.. and the computer froze up:mad:

In a nut shell, anti-dive in the front should be kept below 100% or else it can have a tendency to actually RISE when you hit the brakes. Now the calculator won't take weight transfer into consideration, so in reality it will probably take more like 130-150% anti dive for this to happen in real life.. but any time the suspension gets loaded it potentially want to rise... such as when climbing.

I shot for 70% and it acts normal... feels good... and climbs well.

Roll axis angle is WAY more important overall though as far as driving on the street goes... Basically as the body rolls in a turn, it will input addition steering feedback due to one of the links getting longer or shorter as the inside suspension extends and outside suspension compresses.

Negative = good
Positive = bad

You can affect it by 1) changing the angles of the LCAs as viewed from the top, 2) keeping the LCAs as flat as possible as viewed from the side, and 3) raising or lowering the track bar.

Put the track bar as high as possible(both frame and axle end... it goes off of the track bar's "average" height meaning halfway between both ends)... and if you angle your LCAs inwards this will basically allow them to "intersect" each other if you were to draw a line back to where they would meet if they were infinitely long. Making them flatter as viewed from the side helps too as it keeps that line from raising up in the air to the point that they intersect higher than the track bar.

Here is my 3-link graph... works well... if you have any questions in particular shoot me a PM





edit:

Y-links are terrible because the Y-link center joint is almost NEVER mounted correctly and will be very likely to bend a heim or break entirely. They also have to pivot about that point... so the axle swings wildly left to right... it is worse the more vertical separation that you have at that upper point to the axle tube center line.



FWIW I ran Ballistic 2.63" joints on my lowers, and 3.0" joints for my single upper. I killed all (4) lower joints in about 1000 miles of street driving. So I bought (2) 1.25" heims and (2) Ballistic bushings... heims on axle end bushings on frame end.

Killed the bushings in about 300 miles of street driving.

Now I have (4) Ruff Stuff 1.25" heims and they are all holding up well with a few wheeling trips on them all... Now about 1200-1300 miles since the bushings were replaced... so about 1500 miles on the axle end heims and 1200-1300 on frame end heims.

No problems from the 3.0 Ballistic joints, but they are a ***** to package. Will be using all Ruff Stuff heims from now on. That was a $200 lesson learned.

[RuffedUpXJ]

How are the road manners with the heims? noise?

What size tires you running?

I got my numbers more exact and looking good, 67% anti-dive. Got my frame stiffeners ready as well. Plus I have an order at Red 9 I need to pick up to complete the suspenion. Hopefully the 3 link and relocated shackle boxes will make the XJ ride better and perform better off-road as well.

[flatlander757]

Originally Posted by RuffedUpXJ

How are the road manners with the heims? noise?

What size tires you running?

I got my numbers more exact and looking good, 67% anti-dive. Got my frame stiffeners ready as well. Plus I have an order at Red 9 I need to pick up to complete the suspenion. Hopefully the 3 link and relocated shackle boxes will make the XJ ride better and perform better off-road as well.

I'm running 40" LTBs. And ironically enough I have XJ leaf springs in the back of my TJ

Just buy GOOD heims and you will have no problems... I run the Ruff Stuff 1.25" heims and they have given me no fits at all... No squeeking or anything, I just make sure to shoot them with a bunch of water after wheeling in mud to try and wash away as much grit as possible.

The Ruff Stuff heims are so good because Dan gets them heat treated and then cryo-treated... The cryo treating doesn't have any performance benefits, but what it does is it increases the durability of the nylon lining, and apparently their tests have shown that they are lasting over 2x as long as the non-cryo treated heims.

http://www.ruffstuffspecialties.com/...d5b239a3b66657

Call the phone number at the top of that web page, and talk to Dan directly... ask him about his heims and ask about his thoughts on some of the competitors' products... Ballistic in particular. Every time I've bought heims from Dan, it's been to replace something inferior that I bought from Ballistic

If you buy adjustable joints... YOU WILL BE CONSTANTLY ADJUSTING THEM!!!

I forget who the guy was, but I know that there is some vehicle that has competed in KOH for the last 2 years, and it raced a full season of either XRRA or something like that, and the heims still have no percievable play.


If you want to see how my 3-link is set up or how it rides in person shoot me a PM and I'll give you my phone number.

[RuffedUpXJ]

Revised version of the 3 link with more realistic measurements.



I searched a bunch for what other people have done. And have a good idea but I will be interesting to figure out which side I will put the upper link on. Lots of probelems with each side, driverside has the front driveshaft, transfercase linkage, and the diff on the axle mount and the passenger side has the starter and exhaust too. I know I will have to get into he floor some on either side. I guess I will get all the parts and start on it.

On a side note I got my appointment for the State Safety Inspection since my new XJ had a Missouri Salvage Title for being abandoned.

[RuffedUpXJ]

Had a little extra time last night at work and made up this little guy.

[MrShoeBoy]

If you go passenger side build a truss on the front axle to help spread out the load. I have seen a few failed upper mounts and twisted axle tubes over the years due to poor design/not enough support. Your numbers look pretty close to what my numbers were when I built my MJ. I have since lost all that info when I moved and had a hard drive failure on my computer. Flatlanders setup looks pretty much ideal and his advice is very good. My truck is in Clifton right near UC if you want to come check it out sometime and look at a Cherokee/Comanche 3 link in person. Its currently not running due to ECU issues with the stroker motor and big cam I stuck in there.

AARON