Wandering / drifting on uneven roads

[Gollywomper]

When I’m driving on uneven roads or roads where the crown changes the Jeep will drift a bit when hitting these sections. It not bad, scary or lane changing by any means. Just a tad annoying. Seems to had gotten worse when I turn down my Ranchos to #1 in front and #2 in the rear. It really feels like I am getting rear steer. And seems dependent on pressure on right rear tire at, least that’s how it feels.
Tires are at 25 psi.
Having alignment done today. It was good last spring, but my toe is probably off since I rotated my front pinion a few degrees to eliminate DS vibrations.
It really feels like when the right rear corner goes down the Jeep slightly steer to the left. When the pavement shift back to more level, the RR comes up and Jeep steers back to right. All with zero steering input at wheel.
All this requires small steering changes at the steering wheel to keep straight.
IDEAS?

 

[Chris]

I'd be interested to see how it is after the alignment. Make sure that the caster is good as well.

I assume you don't have a dropped pitman arm, correct?

Also, how are the control arm bushings?

 

[Gollywomper]

Not sure if it will help or not. It drives great on smooth roads. Was not as noticeable before turning shocks down. And feels like it is induced by rear corner squat. It’s not too bad, just noticed the difference. I will also try moving rear shock setting back up a couple clicks too, will slow down some of the rear body roll that seems to induce the issue. Could be a toe problem as well, I guess, that is magnified by other events.

 

[Chris]

It could be a toe problem, or maybe a caster problem.

I've found that even as good as my TJ drives, it still never drives perfectly like our Honda. I just attribute some of that to the nature of the best. Heavy, lifted, piss poor aerodynamics, huge tires, etc.

The alignment shop should be able to tell a lot.

 

[Jerry Bransford]

Could be toe-in, could be from a dropped Pitman arm if one was installed. Check that your air pressure is even between sides and that it's not too high. What size tires and exactly what air pressure is in them?

 

[Gollywomper]

35” tires. Stock pitman arm.
It’s at the alignment shop now. Caster is probably around 5ish. I think it was close to 7* before adjusting pinion for vibration issues. It is not terrible to drive, but definitely more noticeable after turning shocks down from 5-2 in the rear. It’s not like it bounces around on the road. When either rear corner squats from body roll it requires some correction with the steering wheel. Been meaning to get an alignment done so I have some base numbers for future reference. Will report those numbers as well as drivability when turning shocks back up for a comparison.

 

[Gollywomper]

Alignment results

Left. Right
Caster. 4.5. 4.5
Before toe. - .76 -.38
Now. +.13 + .13

Toe was way off. Seems like some of the wondering started last spring when I was adjusting pinion angle. But has magnified with the latest adjustments. Will see how this drives. Then play with shocks a bit if needed. Will report back this evening when I can drive it a bit.

 

[Gollywomper]

Well well well............I learned long ago about tire pressure on light rigs causing issues. Who knew toe setting would be so crucial!!!!!! This thing drives like a completely different rig!!! So glad I don’t have to tighten up my shocks. I really like the softer ride.
Thanks Jerry and Chris.

I guess there is a reason every time these issues come up that tire pressure and toe setting are first on the list.
Can’t wait to see what replacing my none flexing rear uppers does to the ride.

 

[Jonjeeper04]

I just started having this issue on mine, I've rebuilt the whole suspension due to worn components but it wasn't doing it before . I have an 04 tj on 6 in lift drop pitman arm need to double check my tire pressure it was at 25 I believe tires are 35x12.5r15 mtrs in front and gen grabbers in rear. My caster is at 5.2 on left and 5.7 on right I know the cross caster is just enough to cause a pull but it goes both ways not a pull Idon't think but any advise would be appreciated.

 

[Flivver250]

Glad you got it solved.

 

[AndyG]

Toe , track bar bushings, control arm bushings , tire pressure are all interconnected in one sense. A TJ likes it all to be spot on. Also seems you may want a tad more caster , 6-8 but If she drives good , she drives good .

 

[billiebob]

This was always a problem with old bias ply tires as the tread disappeared. Radials are much better but big radials do the same thing on small TJs as the tread wears thin.