So here is the scoop...

93 XJ 4.0, auto, NP 231-J w/AA Sye, using 2 front XJ DS for front and rear

C 8.25 rear with lift springs and homebrew revolver shackles.
Dana 30 front 2 inch springs 2 inch spacers, NEW ball joints, all kinda new (installed about a year ago) TREs and steering stabalizer, RE adjustable Track Bar (Mount is bolted and welded to the unibody)

So I just went from 32x10.5 R15 to 35x12.5 R15 tires. with the 32s i had bump steer (which i know is from my track bar and drag link not being parallel) but it was manageable.
Now with the 35s my bump steer seems to have amplified by about 50% and it has almost sent me into DW but i have time enough to stomp the brakes to stop it from happening (also i was driving under the speed limit to avoid the wobblies).
Now I know my steering box has got to be on its way out because i have about a 1/4 turn either direction before my wheels turn. I personally am believing this to be the main cause of the wobble/almost unmanageable bump steer but i was looking for other opinions.

I have grabbed and shaken my steering and the TREs seem to be fine. The steering dampner would just be a bandaid if replacing that helped any. Im steering away from the ball joints since theyre new. My front tires have damn near identically wear/tread and they were mounted and balanced by professionals (people i always use for my tires. Never any problems with their work). Another possibility i can think of is this, I have a factory tie-rod (so hollow and thin tube) and i think that might be flexing more with the larger tires. So i could begin with upgrading that to the solid Grand Cherokee(??) one that is direct swap.

Thank you all for your opinions and help in advance. I hope I have given you enough info to help me out and make educated guesses. Look forward to hearing from you all! (let me know if I missed any vital info and i will post asap in response)

 

I had the same problem with an 03 ram, it was the knuckle between the steering wheel shaft and the stem out of the power steering gear box.

 

I am pretty sure 35"s REQUIRE upgraded steering.

"Edit"

I have never run them but that seems the consensus. Go to 35"s and plan on doing the upgrade with em.

 

Caster is set at what degree ?

 

I'll check the steering knuckle soon.

What steering upgrades would be considered "required"?

I don't have an angle finder is there another way to check castor?

I'm using stock control arms which i know isn't helping. Also my sway bar is disconnected but would connecting it help with anything? I thought it was just for helping with body roll in corners.

 

if joints and bushings are good, caster is most likely the problem, but you can temporarily fix it by giving a little more toe in until you fix the caster and upgrade steering. the down side is weird tire wear and wandering, so you need to fix it quickly.

my wobble was not so bad on bald 32's, having new 33's amplified the problem.

 

Put 3" and 31's on the wifes XJ and had DW and bump steer. Checked the toe and it was way off. Don't know if it was off before the lift or if the lift threw it off? Adjusted the toe to about 1/8" and stopped the DW. Then put spacers in the lca's and stopped the bump steer. Drives like a caddy now!!!!!

 

Have you not fixed the bad steering geometry yet? That needs to be the first step...

Of course the lift threw it off. You didn't line it up afterwards? You just adjusted the toe in a went with it?

 

Didn't do any alignment at first. Didn't have the big tires for it yet and it was driving good. All the problems showed up when I went with bigger tires. Have been trying to do my own alignment after reading the post on driveway alignment. I think I have everything in alignment now. Drives pretty good.

 

Dont forgot to check your unit bearing on both wheels. This was the cause of DW on my buddies Jeep.

 

[QUOTE=Lowrange2;2711044]Have you not fixed the bad steering geometry yet? That needs to be the first step...

^ This.
My bump steer is caused by my drag link and track bar not being parallel. I'd look at that first. Then have a 4x4 shop align it to where it needs to be. Not necessarily within factory specs on caster.

 

I have drive way aligned it to correct the toe and center the steering wheel (as close as possible.) I did this alignment with the 32s though (fixed the bit of wobbles i had after initially installing my lift)... I would assume tires wouldnt change alignment specs.... as for bad steering geometry, I will be fixing that with a cross over steering set up in January. I will attempt to correct as much castor as i can with shims on my LCAs. worse comes to worse, wheeling will be minimal until about april, which is when i plan on having my 34 ton axles ready to swap in W/ my front leaf conversion.