Asinine

So I jumped into the deep end by going straight to a coilover longarm suspension. I ordered the EVO coilover kits, now sorting through various longarm options available.

All the long arm upgrade kits cost around $2K, but they all are slightly different. Here's what I've learned so far:

Synergy -- DOM tubing, Johnny Joints, adjustable without removing, bent for clearance, doesn't appear to hang down far below frame, bolt-on.
EVO -- Johnny Joints, on Jeep adjustability, arms are straight, front upper control arm mount is rotated 90 from stock, exhaust loop needs to be cut and reattached, mounts don't appear to hang down far below frame, bolt-on.
Rubicon Express -- unknown tubing, not all OEM mounts need to be cutoff, uses custom crossmember, Super-Ride bushings and Super-Flex joints, upper control arms connect to the lower control arms instead of the frame, requires exhaust loop bypass, bolt-on.
Clayton -- Johnny Joints (obviously), square lower control arms, front upper control arms connect to lower control arms instead of frame, uses custom crossmember, PEM fasteners (?), rear mounts hang down quite a bit, bolt-on.
Teraflex -- weld on kit, unknown joints, mounts hang down below frame quite a bit.
Rock Krawler -- weld on kit, solid steel arms, Rock Krawler joints with 1" shank (hard to switch to other joints), requires exhaust rerouting, adjustable anti-squat.
Full Traction -- bolt-on, heavy duty skid plate to protect OEM crossmember, DOM tubing, Heim joints.
Rough Country -- bolt-on, upper control arms connect to lower control arms, custom crossmember, ugly grey color, includes a lot of additional parts like links and brake lines, mounts appear exposed to me.
Rusty's -- DOM tubing, Forged Flex Joints, looks similar to the Rubicon Express kit to me.

I'm sure there's more, that's just the list I've assembled so far. It would be nice if they all published CA lengths and how far the mounts hang down below the frame. I also haven't found which skid plate systems work with which kit, but I'm assuming I'll have to use the vendors skid system with their arm kit.

What's the reason for some kits connecting the upper control arms to the lowers instead of the frame? Is that better, worse, neither?

All the long arm upgrade kits cost around $2K. What's a good objective way to select a kit? I know which kit I'm favoring (today!), but I think this may help a lot of people looking at long arm kits.

TheDirtman

The ones that connect the uppers to the lower arms are know as radias or radial arms and are easier to design and install as you only have 2 control arms on the frame holding the axle on. Pinion angle stays more consistant at droop and does not change due to different upper and lower arm lengths. The weakness would be there are only 2 points holding ton the axle and if you should break something it will be that much worse to get off the trail with.

Teraflex and rustys have their own joints.

You can get most after market joints in a 1" shank. Johnny joints, Duroflex, Ballistic, Heims are all offered in a 1" shank.

Some companies hang the brackets down for simplicity of the build and to increase the upper and lower control arm separation which affects suspension geometry. Of course this drops the arms down and you can hang up on rocks and ledges easier. The closer your seperation the stronger your components need to be as well as the rotational forcer present more leverage on the mounts and control arms.

The longer the arms the better as long as you don't have clearnce issues and you want the uppers to be at least 80% the length of the lowers to control pinion movement when articulating.

big dr

Dirtman,,, your body of knowledge on suspensions is amazing! To the OP,, it looks like your doing some great research on some top notch products. Unless you are willing to have something custom fab'd ( which actually could save you money and be a stronger product for your application) Pic the one you feel most comfortable with and dont look back. Good luck!

JKZinger

With coilovers get a long arm with Johnny joints as a lot of the others without will blow out the bushings. I run them with the EVO double d long arms and it works very well.

TheDirtman

I would agree not to run a control arm that uses bushings. Johnny joints are not the only ones out there but are one of the best. Their new pro joints with the narrow body will give you a lot of misalignment for flexing, although I don't know if you can get them on any arms unless they will upgrade them on the currie kit.

Asinine

What year is your rig? The Double D's are on my short list, but the 90 degree mount is odd - any issues with that?

Asinine

Lots of great info here, thanks for the contributions.

Regarding the radial arm systems, obviously I'm screwed if I break a lower control arm or mount. Is there greater force on the LCAs with a radial arm design and will they break easier? If I've got an OEM style four link, how realistic is it I can limp off a trail if I break a control arm or mount?

Good to know the various joints come in a 1" shank.

How important is on-car adjustability? I'd guess I'll be adjusting them initial and then never again, but one never knows....

Wasn't aware I can blow out joints with this setup. I plan to run Johnny Joints since that's what most systems include and switch the Duroflex if the ride is harsh. The JJs just need a periodic lube, correct? How often do they need to be rebuilt?

Looks like I have a few more variables to fill in, such as arm length and bracket height. I've sent requests out to a couple mfgs, I'm happy to upload my findings for future reference.

TheDirtman

Depends on how bad the break is and if it takes anything else out with it like the driveshaft. All the stress is on the lower control arms in a radius setup.

Johnny joints don't ride harsh but do not absorb vibration like duroflex do. Metal cloak say no go on a 90 degree turned control arm mount.

Typically grease the Johnny joint at oil changes or after a hard day of wheeling. They will last depending on how you treat them. I have been running them for 2 years on a couple of arms with no issues and they are still tight. Ballistic and rock krawler joints use a threaded side to the bearing so you can tighten them up as the internal races wear for a potential longer life vs the Johnny joint. I blew thru a set of synergy poly bushings in about 6 weeks when I first went long arm.

On rig adjustability is not a deal breaker but is nice for doing set ups if you can spend the extra money on it.

36Fan

I would have to piece everything to be happy with a long arm,or fabricate my own. Off the shelf,I would go with Evo's kit.

Dahmer

I read around a lot about radius arms and I could not find one person that recommended them. People that had them said they were great obviously. But all the suspension designers say that they all bind a lot sooner than a 4 or 3 link suspension will. At your level of build I would go with what works best. Most people agree that for off the shelf Evo kits are about as good as it gets.