what would you do/advise?

i am currently running iror fixed lca eye to eye 16 1/4, iror adjustable upper arm currently 15 5/8 eye to eye. caster says 4 degrees measuring on the top ball joint with a angle-finder clinometer phone app. i have all new steering drag-link, tre, measured to 1/8 to 1/4 toe in. bushings on arms all good and tight and newish Moog brand. trac bar is good and tight i had someone shake the wheel as i looked for movement. tires good and balanced, ball joints tight. no shims behind lca

my problem is between 50 and 55 it shimmys/wobbles. i can do 70 just fine and hitting bumps it still kinda holds well its not full on DW. what am i missing?

my other though is i have wanted to get rough country drop brackets but would need a new adjustable lca as mine is dog legged instead of straight so i need either Rubicon express super-ride or rough country x flex. i am looking for lca that adjusts that uses a stock bushing RE looks like it is XJ stock bushing this way i can fix it by going to a local auto store for parts. any advise between the brands? or know of any others?

or i get a iror long arm kit? so 1 setup is 450$ and long arm is 650$
what is your guys input or advise as i ponder what should i do, what should i do....

my driving is everything from city to highway, i am looking for smoother ride and safe. i have read long-arms are bad on a highway however i don't know anyone personally that have them to ask.


1998 jeep xj 6.5 iror lift, iror hd tierod, iror adjustable drag link,
dana 44, 4.56 gears Eaton elocker, disc brakes, truessed,
4.0 engine, apn header, bored throttle body, high flow cat,
cowl air intake, accel igniton wires and cap,

Rotate your tires, front to rear.

See if it shimmys at 55.

dont drive so fast. stay 50 or below, its safer.

1/4" toe is too much. Move it to 1/16-1/8" absolute max

4 degrees caster is too low, you need to get it to 7ish

i had it at 8 degrees and it full on dw at 55. dropped it to 6 to 7* and it still wobbled out of control when i got it to 4-5* this morning and currently thats what i am sitting at i can at least drive it. but between 50 to 55 it starts to wobble i.e i can feel it shaking.

Rotate tires and see if it changes

I just rotated my tires but have not got to test drive yet.

rotate or have the tires rechecked for balance.
i would throw more castor at it if you can tolerate it and check the upper control arm bushings. in rare cases i have seen them cause a wobble/shimmy when everything else seems tight.


also... why does the dog leg in your control arms warrant replacing them if you get control arm drop brackets? the point to point relationship remains the same in either case. the dog leg is there to clear the shock mount at full droop.

Figured the lowest point in the arm when attached to a drop bracket would cause it to v and collapse.
I have the iror fixed lower control arm. So i thought with a drop bracket i would need a straight adjustable lower arm.

Tires can be out of round and cause it. I had a set of tires that were slightly out of round that caused DW. Replaced them with a different set and it went away but not after it trashed a new moog trac bar.

No, my tires get balanced often just have not rotated them in 7500 miles so i just did but have not been able to test drive it yet.

Balancing will do nothing for a tire that is out of round other than you may need a ton of lead to do it. An out of round tire can be perfectly balanced and still cause DW. Any good tire shop can spot trouble tires, the problem is there are VERY few good tire shops where the employee's actually know anything other than how to mount and balance tires and half the time they can't do that correctly.

fuelfox4949 said:

Figured the lowest point in the arm when attached to a drop bracket would cause it to v and collapse.
I have the iror fixed lower control arm. So i thought with a drop bracket i would need a straight adjustable lower arm.

Click to expand...

no sir. your arms will work just fine.

i actually prefer fixed lowers... no jam nuts to worry about beating up on rocks.

I don't think your alignment is causing the problem. But, as people said above, take some toe out of it. Straight ahead is just fine. Or just a tiny, tiny bit of toe. Lots of us run too little caster with higher lifts. It doesn't cause wobble, just more wander at speed.

I don't like the idea of 6.5" of lift with stock length arms and a stock style track bar. Heck, I wouldn't want to do that much above 3". Long arms are real nice. They ride much, much better and flex better too! If you want to use this an excuse to buy a set, maybe whatever is wrong will go away!

Assuming you are talking about Iron Rock stuff, I'd do their long arm upgrade in a heartbeat, were I you. And I'd also add on a nice track bar. I also think that Core's stuff looks really nice for the price.

Paul

What is the front pinion angle?
After regearing to 4.56s, my XJ had a vibration that started at about 50 MPH. I reset the front pinion angle to about 1/2 degree, which cured the vib.
The FSM indicates that the front pinion angle should be at 1 degree or less and that pinion angle supersedes the caster. Excessive pinion angle will wear the front u-joint out more quickly.
The lower the gear ratio, the faster the driveshaft spins, increasing the likeliness of vibrations.

My Jeep ran great but i had to take out the 2 inch coil spacer to get my bumper back to street legal. After i took that out i got dw. So i spent the weekend aligning and trying to get the caster right, toe right, i had no vibes yesterday at 70 on the highway but at 50 it started shaking.

I don't believe it is my tires as they worked great with the spacer in.

I am looking for a smoother ride so i am getting feed back on my options while trying to get my Jeep set up correct right now.

How far do drop brackets move your arms down? I hear 2 3 4 inches from all different searches. Currently looking at rocky road drop brackets or rough country.

ok so i took it in for a alignment and the print out has my caster at 4.4 degrees and my toe is set to 0. driving straight it feels fine and smooth however driving it home i took a pretty common curve at 50 mph and it started shaking heavy up front.
rotated and balanced my tires and they were all good and not out of round, i am running out of ideas.

should i adjust my upper arms about 1/4 inch in to pull my pinion back and increase my caster?

fuelfox4949 said:

ok so i took it in for a alignment and the print out has my caster at 4.4 degrees and my toe is set to 0. driving straight it feels fine and smooth however driving it home i took a pretty common curve at 50 mph and it started shaking heavy up front.
rotated and balanced my tires and they were all good and not out of round, i am running out of ideas.

should i adjust my upper arms about 1/4 inch in to pull my pinion back and increase my caster?

Click to expand...

VAhasnoWAVES said:

rotate or have the tires rechecked for balance.
i would throw more castor at it if you can tolerate it and check the upper control arm bushings. in rare cases i have seen them cause a wobble/shimmy when everything else seems tight.


also... why does the dog leg in your control arms warrant replacing them if you get control arm drop brackets? the point to point relationship remains the same in either case. the dog leg is there to clear the shock mount at full droop.

Click to expand...

i would try throwing more castor at it. i am a fan of excessive castor, it seems to help with large tires. i am in the 6-7 degree range, but my Cs have also been cut and rotated (and i have locking hubs).

but with your stated lift height you may be able to tolerate much more... i would add shims/washers behind the LCA shoe rather than shortening the uppers. give that driveshaft the best chance you can to be happy.

well i just went to adjust my upper arms a little and on the axle side mount the collar that holds the bushing i was able to push out with my finger and tap the other out so im thinking that is not helping anything. them being loose in there.
so i will buy new bushings and press them into the axle, i will make some shims to add more caster and try again.
where are you reading your caster angles from?