home brew mid arm

[builder]

seriously thinking about doing my own mid arm 3 link modelded after skyjackers rock ready system.lookin at 4.5-5" lift. what do you master fabbers think about this idea? and for the record i do not care for the RE drop brackets.thx Ray

[WTF]

In my opinion, fabbing the system you're talking about doesnt make sense.

What advantages do you have in mind for a mid arm over a long arm setup?

Why spend the time to fab a mid arm system when it will take the same time, effort and money to fab a long arm system that should out perform the other option?? :dunno:

[builder]

several reasons why, no long arm unloading,no brackets hanging down back near your crossmember, which is near the middle of your rig.not looking to argue point.guess to each there own and maybe i should have titled this thread hey mis arm guys thx for input anyway! Ray

[MrShoeBoy]

A well designed and executed long arm setup will be just as effective at controling unloading and other handling quirks as a mid arm setup. You just have to put forth the effort in designing and building it.

As for the mid arms, if you have the fabrication skills go for it. Theres very few mid arm guys running around, goatman is the first who comes to mind, and they seem to be doing well so long as you put in the time and energy to design and build them correctly otherwise it will be a waste.

AARON

[Fullsizexj]

I run midarms on mine and they work great

[Goatman]

I've always wondered why mid arms haven't caught on more than they have...................oh wait, I guess they aren't as cool as a long arm.

We've been over this time and time again. It's the overall angle of the arms that makes a difference, not the length. And it's an issue of ground clearance. It's easier to get good LCA angles with a long arm, but it's not easier to get good ground clearance or optimum UCA angles. Building a suspension with the best possible arm angles and best possible ground clearance is more important than how long the arms are. There's nothing wrong with a well designed long arm, and there's nothing wrong with a well designed mid arm. One big advantage to building a mid arm rather than a long arm, if you're fabbing your own suspension, is that the mid arm is easier to build with the desired good ground clearance.

One reason that the Skyjacker mid arm suspension is popular with Jeepspeed guys is because it works. Any one that has followed me, Paul S, or Hinkley around knows that our mid arm suspensions work, whether it's crawling or hauling ass. There are also nicely done long arms out there that work very well, but there is no concrete reason to do a long arm over a mid arm, it's a builder preference choice.

BTW, my new buggy has been working pretty damn well, climbing pretty much everything out there..........the front is a mid arm.

Go for the mid arm, you'll never regret it. :D

[builder]

i have already decided to go mid arm.build my own based on the skyjacker design.what i was wondering is if making it a 3 link instead of 4 link would work ? if not i will keep it a 4 link thx as always Richard for your input.

[Goatman]

i have already decided to go mid arm.build my own based on the skyjacker design.what i was wondering is if making it a 3 link instead of 4 link would work ? if not i will keep it a 4 link thx as always Richard for your input.

Sure it will work as a 3 link. Mine, Paul's and Hinkley's are all 3 link.

I think there's much easier ways to build it than following the SJ design, if you're building it yourself. What did you have in mind?

[builder]

one i like the stock upper arm idea with the skyjacker design. i understand they will have to be moved down to match the lower arms. and i know you are not a fan of losing ground clearence from reading many threads. and i was just planning on going with skyjackers design as far as the lowers are concerned and making some custom arms.and even ramping the lower bracket as well.all this minus the tranny part of the sub frame.i know you do not care for the loss of ground clearence. but at least the lower arm bracket is not hanging down back by the crossmember but up near the original lca bracket. thx Ray

[Goatman]

A slightly lower control arm bracket doesn't hurt you when it's close to the original position. It's far enough forward that it doesn't effect breakover angle, and rocks will slid over the mount (or the other way around). I think the SJ design is a good one, it just looks like a lot of work to try to duplicate. It could be simpler to just make a mount where you want it............which is what you might be talking about, just using the SJ positioning.

My frame side LCA mounts are lower than the stock position, without any ill effects. The frame side mount being slightly lower and further back, and the axle side mount being higher, even with the axle tube, is what makes the arm angles real good.

[xj92]

I'm in the process of doing a mid-arm on mine. I have the lowers done, they're around 25" or so and they're mounted slightly back and maybe just a hair lower than the stock mounts were. I have most of the materials to do the uppers but haven't got around to it yet, although I'll be doing two uppers. One upper should work well also as long as everything is beefed up and you use re joints on both ends (or heims, jj's, whatever doesn't deflect any or at least not much).

[IntrepidXJ]

i kept short arms and raised the mounts on the axle.....so i get the benefit of better angles plus better ground clearance......i'm really happy with the setup, and it's not very difficult to implement

[xj92]

Did you push the axle forward or shorten the LCA's?

[IntrepidXJ]

Did you push the axle forward or shorten the LCA's?

pushed the axle forward a little bit......mounted the coil buckets centered over the axle tube

[builder]

yes i want to make my own mounts both upper and lower frame side. i like the idea of keeping the uca arm in the stock position on the axle and the stock length.the skyjacker design on the lower arms is basically 4" down and 2.5" back.using the lca stock axle bracket. uppers use stock length arms basically dropped 4"s.lcs arms being about 20"s.at 6" lift height.the big question i am asking is if i stick with this design can i run a 3 link? and i realize i would need to use jj"s or heims on both sides with a 3 link. i also am aware that i can tweak frame side mounting positions frame side lca mounts for a lil better clearence and ajust uca mounts frame side accordingly thx again guys for the input. Ray

[Goatman]

My lowers on the frame are 2" lower and 2.5" back, but the mount is stronger than the stock mount so the bottom of the mount is only 1.5" lower than the stock one. I built new mounts and beefed the hell out of the frame in that area, however, I think the easiest and best way for someone to make a slightly longer arm is simply to cut out the back of the stock mount and add to it. I think you can add to the back of the mount and plate across the exisiting mount carrying it back, and it would be simple to do and strong. All stock and aftermarket arms, and all JJ's and other joints that are used for arms, are a 2 5/8" width. It's easy to make mounts out of 3" boxed tubing 3/16" wall, which gives you a 2 5/8" ID. You can cut that stuff a variety of ways to make any kind of link mount.

If you want a fairly simple way to lower the uppers 4" and keep them the stock length, get a set of drop brackets that someone is discarding and use only the top part. I did that on my front end when I still had a D30. However, to get the benefit of longer lower arms it helps to make the uppers longer too. Otherwise, you have to be real careful of your arm placement and overall travel because the difference in arm length can potentially give you some nasty pinion angles. I made a new upper mount a little lower and a little back from the stock location, and used a slightly longer arm, but my axle mount is also much higher than stock. My current upper arm is an old lower arm. Here's a couple of pics of mine if it helps to give you some ideas.

http://fototime.com/87D7BF1CF0BEE47/standard.jpg
http://fototime.com/9A67FD3287ED63D/standard.jpg
http://fototime.com/B5C4DE084DE0FDB/standard.jpg

[Captain Ron]

There's another big advantage to mid arms.

Rigs with mid arms fit on vehicle lifts way better than ones with long arms.

:D

--ron

[Phil]

There's another big advantage to mid arms.

Rigs with mid arms fit on vehicle lifts way better than ones with long arms.

:D

--ron


So that's why I had to roll around on the ground all summer?

[builder]

Thanks for all the help everyone. now as far as the ass end i am going with f 150 leafs moving the front mount and the rear also. one question regarding the rear mount. i know a lot of people move it even with stock springs, in order to get proper shackle angle. it appears to be about a 1.5 inches forward. is there a magic number? appreciate any input.O.R.D>moves it forward on there kits for chevys also. oh and i will be moving the mount down also for some lift gains and using a boomarang shackle.

[Goatman]

How much longer is the back half of the spring than the stock springs?

I used MJ main leaves, which are 2" longer in the back half (3" longer in the front), and didn't change the shackle mount location, just used a boomerang shackle.

[Gaius]

Poly Performance makes nice lower control arm mounts. I used them on my recent midarm on my TJ.

I was planning on doing a long arm on the XJ going to the crossmember, but after jow well the TJ came out I might go with a mid arm for that.


http://www.pbase.com/image/80160761/large.jpg

http://www.pbase.com/image/80391952/large.jpg

[builder]

2 " in front and 2.5 in back of leafs. how long of a boomarang did you use?

[builder]

and Gaius how long are your lower control arms? and how far does that bracket lower the lca from the frame? what 2.5 inches? thx Ray

[Gaius]

My lowers are 26 inches. I'll have to measure the whole mount, but I think the bolt hole is 2 inches below the mount, so 2.5-2.75 sounds right.

[builder]

ok thx i am going to about a 20" lower control arm. want to keep it close to factory mount and as far forward as possible and still get the gains from longer arm and i am also going 3 link thx again Ray

[xj92]

I used S10 leaves and boomerang shackles on mine (S10 main leaf & all). It rides great, has a good shackle angle, etc. I have the C-Rok rear bumper, so no cutting or modifying was necessary.

[Root Moose]

Gaius, did you relocate the UCA for the upper arms at all? If not I guess your setup is pretty similar to the TerFlex long arm kit for XJs.

[Gaius]

Not yet, but I'm planning to. I actually took of a Terflex longarm off it (horrible brake dive with stock uppers) to make them. I'm swapping in a 5.9 into it right now.

The fisheye plate you see is to mount the upper link to.

[Root Moose]

The fisheye plate you see is to mount the upper link to.

I was wondering about that. You doing any calcs for dive and such or just letting the required clearance put the UCA where it needs to be?

[Gaius]

I was wondering about that. You doing any calcs for dive and such or just letting the required clearance put the UCA where it needs to be?
I'm just letting the clearance denote mount placement and building adjustability into the upper mount. If it's not enough I'll raise the lower axle mount.

I did my rear 4-link using basic knowledge of instant center and really let the clearance tell me where the mounts go. Both lower mounts and the axle upper mount really are locked in. Just build adjustability into the upper mount. i try to get one inch past parallel up, and two or three inches past parellel down, if that makes any sense. Here's my 4 link, at about 100% antisquat.

http://img157.imageshack.us/img157/2267/4linkfinalpics018fx1.jpg



Upper mount:

http://img267.imageshack.us/img267/6011/tj4linkalmost007ts2.jpg

[Goatman]

2 " in front and 2.5 in back of leafs. how long of a boomarang did you use?


I used the 6" long heavy duty shackles that I was already using and made my own boomerang shackles out of them. Basically, I welded tabs on the bottom rear of the shackle, with a triangular brace on top of the tabs, and holes drilled for the spring bolt. Ground the welds flat so you can't tell there's any welding on them. Mine are 2" longer with no problems, you should be fine doing the same thing for 2.5".

[builder]

ok thanks a lot Richard,thats what i am going to do.