Death Wobble with new 3" Rough Country

Sorry in advance for long post,

I am a first time Jeep owner as of 2 months ago and loving it!!!!
I have a 93XJ w/165k. I just installed 3" RC coil springs and GM 1/2 ton full length AAL's (forgot those shorty RC AAL's). My lift ended up about 3.75" in front and around 4" in back. I made 1" aluminum spacers to drop the transfer case. I was getting pretty serious DW's at 50-55mph with normal driving. I did the following in this order:

- set the caster to about 7 degrees and set the toe-in to 1/8".
- checked out trak bar torque and wear (not bad for 165k).
- had 235-75R15 tires balanced.
- put a stock steering stablizer on (free, off an XJ with 90k)
- passenger side rotor seriously warped, replaced both rotors.
- set caster to 6 degrees.

Each of the these improved the DW a little better. Now it only happens when I hit a pot hole real hard about 50-55mph.

Now for questions:
- My tires are very questionable and worn (but balanced), could this cause my DW?
- What is the recommended caster for a 3" lift?
- I believe the control arm bushings are fairly worn (oil leaks, etc) can i keep the stock LCA/UCA's and just change the bushings?
- Should I get new stabilizer???
- What's my next move?

My buddy is willing to lend me his 31x10.5 BFG's to help me eliminate the tire questions.

THanks in advance... You guys are doing an awesome job!!!!!

Eric Fernald

efernald said:

Now for questions:
- My tires are very questionable and worn (but balanced), could this cause my DW?
- What is the recommended caster for a 3" lift?
- I believe the control arm bushings are fairly worn (oil leaks, etc) can i keep the stock LCA/UCA's and just change the bushings?
- Should I get new stabilizer???
- What's my next move?

Click to expand...

Your post is very descriptive and includes some good info.

Tires can play a very big part in death wobble, but you said you only have the problem when you hit a pot hole at ~55MPH. This indicates that the tires aren't the problem. If it were the tires, you would experience wheel shimmy at a similar speed that might progress into death wobble if you hold that speed or hit a small bump.

It's my opinion that 6° is a good target for castor at any height. More than this will result in pinion angle problems. You're lucky that 6° works for you. I would change the toe-in to the factory recommeded 0. Running any significant amount of toe-in is only covering up other problems and will increase tire wear. The resulting tire wear will contribute further to death wobble problems.

If you can detect wear in the control arm bushings or any other front end/steering components, replace them. At 165K miles it's likely that most joints are ready for replacement. This can include control arm bushings, sway bar bushings, tie-rod and draglink and trackbar joints, steering box, steering shaft joint, ball joints and wheel bearings. Anything that can allow play in the steering can give shimmy a foot hold to progress into death wobble.

At 90K miles, I would definitely replace the stabilizer. You can remove it and test for resistance. Take particular note of how it controls short stroke movement in the 1/4" to 1" range. If there is little resistance in this range, replace it.

Double check every joint, bearing and bushing in the front end. Your alignment specs are close enough to indicate that the problem is excess wear somewhere.

Borrow the tires just to see how nice 31's work on a 3" lift. That's a good combination. Good luck and keep us posted.

I had to replace my stock LCA's with the ones that came in my skyjacker kit to fix my death wobble, just my experience.

xj92 said:

I had to replace my stock LCA's with the ones that came in my skyjacker kit to fix my death wobble, just my experience.

Click to expand...

replace control arms = change in bushings + change in castor

efernald said:

Sorry in advance for long post,

I am a first time Jeep owner as of 2 months ago and loving it!!!!
I have a 93XJ w/165k. I just installed 3" RC coil springs and GM 1/2 ton full length AAL's (forgot those shorty RC AAL's). My lift ended up about 3.75" in front and around 4" in back. I made 1" aluminum spacers to drop the transfer case. I was getting pretty serious DW's at 50-55mph with normal driving. I did the following in this order:

- set the caster to about 7 degrees and set the toe-in to 1/8".
- checked out trak bar torque and wear (not bad for 165k).
- had 235-75R15 tires balanced.
- put a stock steering stablizer on (free, off an XJ with 90k)
- passenger side rotor seriously warped, replaced both rotors.
- set caster to 6 degrees.

Each of the these improved the DW a little better. Now it only happens when I hit a pot hole real hard about 50-55mph.

Now for questions:
- My tires are very questionable and worn (but balanced), could this cause my DW?
- What is the recommended caster for a 3" lift?
- I believe the control arm bushings are fairly worn (oil leaks, etc) can i keep the stock LCA/UCA's and just change the bushings?
- Should I get new stabilizer???
- What's my next move?

My buddy is willing to lend me his 31x10.5 BFG's to help me eliminate the tire questions.

THanks in advance... You guys are doing an awesome job!!!!!

Eric Fernald

Click to expand...

I have the RC 3" kitt on my 88 with the factory track bar, and Lca's. The only thing i did is set my tow in at 1/16" after the install. The jeep rides great with no alignment issues except very minor bumpsteer which is hardly noticable.

Did you change your Pitman Arm or are you running stock?

I am running a stock pittman arm.
and I have an update, today I did the following:
- Set the toe back to "0" from "1/8" and couldn't reproduce the DW at all.
- Put my buddy's 31's and still couldn't reproduce the DW at all and the ride improved tremendously.
- Went through and examined all joints and found the LCA's and UCA's are in pretty good shape (not alot of play). But, the trac bar tie rod end is shot, when moving the steering wheel back and forth there is too much movement at that joint. Tried to torque it down but didn't improve anything.

I still get slight wobble when i hit hard roads at 50-55mph. But,
I am very happy with the findings. My next move is to get a new trac bar and steering stabilizer, and then start replacing bushings.
Oh yes, and finally 31's and homemade skidplates so I can go play in the mud!!

Thanks again for all your help!!!

Newly born-again Jeep finatic
Eric Fernald