Front 3-Link Setup

RuffedUpXJ · 01-19-2011, 12:15 PM

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 · 01-19-2011, 01:59 PM

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 · 01-19-2011, 04:54 PM

Why not Y link it?

RuffedUpXJ · 01-19-2011, 09:21 PM

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 · 01-20-2011, 09:18 AM

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 · 01-20-2011, 10:40 PM

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.

01-19-2011, 12:15 PM	#1
RuffedUpXJ On XJ 2 Now Join Date: Feb 2007 Location: Fairfield Twp. Posts: 314	Front 3-Link Setup 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. __________________ 88 XJ - 5" lift - 35" BFG's - Bumpers - Rock Rails - Homebrewed OBA - Roof Rack - Tube Doors - Trimmed - Dented 87 XJ - D44 - Disco D30 - 235's - 231TC - Stock for now

01-19-2011, 01:59 PM	#2
yellowjacket barely breathing Join Date: Mar 2008 Location: alexandria, ky Posts: 889	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. __________________ my next rig will be on the trail before zuk 2.0 will

01-19-2011, 04:54 PM	#3
itbrokeagain Just Empty Every Pocket - CORE Member - Join Date: Feb 2007 Location: Amelia Posts: 1,435	Why not Y link it? __________________ 91 fj 80 on 37 Nitto Muds with a 10k winch. Cage and sliders coming soon. Last edited by itbrokeagain; 01-19-2011 at 05:01 PM.

01-19-2011, 09:21 PM	#4
RuffedUpXJ On XJ 2 Now Join Date: Feb 2007 Location: Fairfield Twp. Posts: 314	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. __________________ 88 XJ - 5" lift - 35" BFG's - Bumpers - Rock Rails - Homebrewed OBA - Roof Rack - Tube Doors - Trimmed - Dented 87 XJ - D44 - Disco D30 - 235's - 231TC - Stock for now

01-20-2011, 10:40 PM	#6
flatlander757 Fartface extrordinair Join Date: Aug 2010 Location: West Carrollton Posts: 127	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. Last edited by flatlander757; 01-20-2011 at 10:46 PM.

01-20-2011, 09:18 AM	#5
sarge Pure Bacon Join Date: Jan 2007 Location: Trenton, Oh Posts: 1,098	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???