Mid arms

Posted from a PM:

i had a couple questions i was hoping you could help me with. my xj currently has 3" and 31s, but i would like to go about 6 or so with 33s. rather than go with the RE drop brackets or a long arm kit that will eat up my clearence i would like to do like a mid-arm setup. problem is i dont have a welder. however, i know a guy that has a private shop that could probably weld up some new mounts for me a little farther back on the frame.

basically, what im trying to figure out is if there is a lower control arm that i could buy that is about the right length and would work with the mounts a little farther back. while doing some searching i found an old thread where you said currie "j" arms will work. i tried searching for those a little bit on the web and didnt have a whole lot of luck. all i found really found was their site: http://www.currieenterprises.com/cestore/categories.aspx?id=993
and about half to three-quarters down there is some J arms. are these what you were talking about, do i want the J bend? i didnt think so, but im not sure.

also, what im trying to figure out is if i need to weld on new mounts for the uppers, and also what arms to go with for them. can i leave the mounts where there at and use some say RE adjustable uppers.

ultimately, im trying to find a good setup that will flex well and not just rush into a long arm, or drop brackets.

what do you think?

FYI-my xj has and will keep the d30 up front.

Jake

It's too bad that no one really markets a mid-arm suspension lift, other than Superlift. There's really is a mid-arm, since they reposition the mounts and the arms are longer. It's not a popular kit since they've had trouble with the strength of the upper arm axle bracket, and it uses all rod ends.

The J arms will do somewhat of the same thing for the bottom. They use the stock frame mounts but you have to weld new mounts to the axle housing on the front side of the tubes. The J arm goes under the axle and attaches in the front, but it helps since the longer arm still increases the arc of movement of the axle.

It's pretty hard to do a custom suspension setup without time and welding ability. The lower mounts aren't hard. Use some 3"x3"x3/16" boxed tubing for the mounts, since that is 2 5/8" ID, which is what all suspension components are. Cut the back out of the stock LCA mounts and weld a section of that 3x3 tubing (with one end cut out) to the back of the mount, and drill the hole lower than it is in the stock mount. Figure a way to move the LCA axle mount up also, or just cut them off and make some new ones from the 3x3 tubing. Lowering, and moving back, the UCA frame mounts is a little more difficult. You'll have to look under there and figire something out. Check out my pics to see how I did it.

http://fototime.com/inv/28A8BDEAA47438F

Hope this helps, have fun,

Posted from PM:

well, the idea with the 3x3x 3/16 box tubing sounds good, and i think that the guy i know would have no problem whatsoever making those for the lowers.

however, i just dont know about what to use for the lca's. he could maybe make some, so i think i will talk to him. so theres no lowers that are already made that seem to be about the right length, of somewhere near 22-24"? huh? well actually, do you know at all what length the lowers should be as well as the uppers?
Also, i still keep the system as a 4-link right?

also, what do you believe are the best ends to use if i were to have some made?

Maybe im dumb, but i guess i just really dont understand how the currie J's work then, under the front axle and mounted to the front?? seems wierd to me.

but if you know those measurements, and what ends i should use for all the arms, that would be awesome

thanks again, Jake

The idea of the J arms is to get longer arms without a lot of special fabrication....just new mounts on the front of the axle. Even though the arm runs under the axle and attaches in front, it's still longer and so decreases the arc of movement of the axle, which is part of the goal, along with flattening the angle of the arms. Hinkley and Erik run J arms and like them, and they are an improvement over the stock arms. Currie ran J arms on their first competition rig, and it won second place in the overall standings in the first season of ARCA (was in 1st until the last day of the last competion and then they broke).

The length of the arms isn't too important in my mind. Longer is better to a point, but then it becomes a balance of length and ground clearance. A little longer than stock is good enough, it's the angle of the arms that really makes the difference. My lowers are 19.5", which is roughly 3" longer than stock, and my upper (3 link) is 17.5", which I think is 2" longer than stock. On mine, the lower frame mounts are 2.5" back and 1" down from the stock mounting position, and the lower axle mounts are even with the tubes. The upper frame mount is 2" lower and 1" back from stock, and the axle mount is 3-4" higher than stock. It's the mounting position, more than the length of the arms, that is the big benefit because of the low angle of the arms.

Arms can be made from tubing and weld in threaded inserts, which can be bought from any number of places that sell fabrication parts, like Spidertrax, Avalanche Engineering, Bluetorch, and on and on. Johnny joints are the prefered end to use, and the RE joints are better than the Currie joints because they can be tightend up by turning the threaded washer, while Currie's need to be taken apart and a thicker washer used. You can buy the JJ's and then weld on the bolt of choice for the threads that go into the arm. Rod ends are also good, but the lowers will need at least a 1" rod end, or a 1 1/4"......3/4" won't hold up at all. Rod ends will transfer more noise and hashness into the body than bushings or JJ's will, so that's something to consider if it's a daily driver. There is a new joint called a jimmy joint, that is a cross between a JJ and a rod end. It's shaped more like a rod end but used plastic races like a JJ, designed to provide more movement, but I have no experince with them. For our heavier rigs I'd stay away from them until they're used long enough to get some longevity reports back. As far as arms that are out there, the longest arms that come in a kit are the Superlifts, but I don't know the length. They should work on a custom setup. You can buy some arms and then lengthen them, which is easy to do. My arms are Currie arms, which I cut in half and sleeved to make them longer, and also much stronger.

3 link or 4 link is up to you. If you're going to use the stock upper arm axle mounts you need to stick with a 4 link, that bushing won't last long at all with a 3 link.....it hardly lasts long with a 4 link. If you switch it out for a JJ, which I think Currie makes now, you could try the 3 link, but be sure to brace the mounts really well.