I was planning to build some adjustable lower control arms, but short arms almost do not seem worth it

planning to build some long arms for the XJ... need some ideas y, 3, or 4 link?

this is being done to get ready for my upgrade to 4.5" (sitting at 3" right now)
I will do this with a simple coil spacer in the front and a shackle in the rear (eventually I plan to purchase a 4.5" HD coil front Rusty's)


planning to tie into the stock transfer case cross member and reinforce it

and making brackets out of 1/4 steel

most likely I will be running Ruff Stuff hiem joints and maybe there poly bushings on the other side to cut down on road noise (this is my DD for now)

what material should I use for the tube on the arms?




GOALS of this project:

1.) MORE flex

2.) better ride quality

3.) more strength (this will not be hard at all considering I am still on stock arms right now)


Pros and cons I can see so far

the Y link seems like is it would be the weakest of the 3 options, and to me it seems like it would be more complicated to figure out the angles, further more it seems like the vehicle would be a little harder to drive, something about the way this type works confuses me a little, seems like a y-link would loose caster as it flexes... the more it flexes the worse it gets

the 4 link and 3 link should flex the best but it might not ride quite as well as the y link (from what I have read)

the 3 link should be like the 4 link but it would cost around 25% less to build

 

Problem with three link is if a upper link or joint goes, so does the axle. IMO it comes down to strength v flex. If it's a DD I'd err on the side of strength at the cost of a bit of flex.it sounds like you have a good plan so far. I've been bench building my long arm kit since I got my xj. I'm just waiting for some warn weather to get started. Btw I'm doing a 4 link 2" 1/4"wall lowers 1.5 on the uppers. Good luck!

 

how did the name of my thread end up like this? I thought I named it something else?

 

The choices really reside on what you plan on doing with it.

I'm a fan of the 3-link and am building one for my Comanche as we speak. Yes, if the upper arm breaks, bad things happen, but the way I'm building it, there is so much strength in the upper that there shouldn't be an issue.

The y-link setup, while gaining popularity, will change caster and pinion angle as it flexes. These are easy setups to make but skimp on some of the most important aspects of offroading.

The 4-link is a time tested setup, but it binds on major flex, something the 3-link doesn't do. Bother the 3-link and 4-link keep their caster and pinion angles fairly constant through all the whole range of articulation.

For my 3-link, I could care less about noise as I'm going to be running MTR's on the street, so I went with the solid bushings on both sides. I'm running a 2", 1/4" wall DOM for all three arms with the 2 5/8th Ballistic Fab joints on both sides, drilled for a 5/8th in bolt.

I'm building the crossmember out of 1/4", 2"x6" box tubing that will have 1/4" plates going up the sides of the frame with crush sleeves welded in. I would stay far away from building off the stock crossmember due to it being so thin and flimsy. My setup is a bit more complex due to the Chevy 350 that is going in there but you should be able to line all the holes up with your stock crossmember on the box tubing.

As for heims, they are great joints but you will need misalignment bushings if you want them not to bind.

Hope this helps to answer some of the questions.

 

link set ups are not for first time fabers. there is a lot to them anti squat, roll center castor and pinion angles axle locations ect. The stock crossmember will not support a link setup. its designed to hold the trans and t-case not locate an axle and take loadings from the front.

I've though about building my own links in the past but the time investment on setting up a 3 or triangulated 4 link is not worth it with the options that are on the market right now. for $900 you can get a new HD cross member and arms. I've priced out the steel joints and tube adapters I needed to build my own. Low and behold your not saving much money maybe $100 if you get it right on the first shot.

IMO get a Clayton, Iron Rock offroad, TNT offroad, Rock Krawler, Ect Y or 3 link kit and call it a day. its under your rig in a weekend the geometry is already planed out bolt weld and wheel. VS spending hours with a link calculator, making up links waiting for parts that you forgot to order of didn't know you needed.

That's just my .02

 

Irongrave is right, this isn't for a first time fabricator, there is a lot of math behind the true long arm setups (y-link setups are easy to build without too much geometry but you give up a lot of benefits to go this route).

Heims save you a ton of money, same with the rubber bushings, especially compared to what I spent on the Ballistic Fab joints. I think I'm up to around $750 for everything but my arms and brackets are much thicker and the mounting brackets are going to be set up much higher for a flatter stomach, not to mention a custom transfer case skid that fits my application perfectly.

As for the 4-link, there really isn't too much triangulation you can do to the front and there really is no need for it with the panhard/track bar. The whole point to the triangulation is to keep the axle centered, which the track bar takes care of.

As much good press Clayton gets, I personally would stay far away from them. From the setups I've seen, they use the stock bolt locations for their long arm crossmembers. This is fine for street driving on nice and flat ground but when you hit pot holes or go wheeling, there is a lot of shear forces that go on these bolts and the stock 3/8th inch bolts that hold the crossmember would easily shear off. If you do add a Clayton setup, think about reinforcing it a lot better than they do.

I would stay far away from a y-link setup if you plan on flexing and the 3-link, true 4-link setups hang low. The 3-link and 4-links keep their caster and pinion angles fairly constant when using equal length arms and anti-squat and roll center get taken care of through the vertical separation between the arms. If you build (or buy) a bracket for the upper arm that has multiple holes drilled in it, you can fine tune the anti-squat easily starting at around 7" separation.

 

Just a note on claytons kit the side part of the crossmember is meant to be welded in and not relay on the 2 bolts those are just to locate the crossmember before welding

 

Good call

 

Welded in or not, that's still a lot of stress in one small area. Maybe I'm just looking at it at the engineers point of view or I just prefer to massively over do stuff on the side of safety but I prefer the stress to be spread out in a larger area than that.

 

I am not a first time fabricator, did motor cycle stuff for a while actually

 

my plan was to extend the cross member in both directions (front to back) and then weld the mounts to that

either way, it WILL NOT be as weak as the stock mounts...

 

I say go for it! Jeeps are all about trial and error, and steel is a very open medium. Start with ur plan with some beefy tacks cycle it if it looks good burn it in. Worse case you cut it out and start over. For me it's not about saving money, it's something I can call my own. Not saying that's for everyone, but to each his own. Gota break some eggs!!

 

The only issue with trial and error on control arms is they could hurt him or someone else or severely damage the Jeep. Using the stock crossmember could be a nice starting point but just make sure you reinforce it nicely and add extra mounting points to the frame.

The next part comes down to what setup you are looking at. If you're building a 3-link, error on the side of safety and overbuild the upper arm. Whatever setup you choose, reinforce the stock mounts on the axle end and think about using a larger bolt than the factory 9/16th.

 

I figured that a 7/8 ruff stuff heim should be enough for the upper, but a 1.25 heim would be awesome