Geometry options and opinions.

So I'm going through and upgrading parts in preparations for another new york winter..yay...However now I have bad wander and bump steer. From my reading, the track bar and drag link have to be on the same plane, or as close to it as possible.

I have/had the Rubicon Express 4.5" Super Flex lift (RE6130). Was going through and replacing their known to fail POS bushings. But I decided to just replace some components.

New Parts:

• Core 4x4 Adjustable upper and lower control arms, (surprisingly stout).

• Rugged Ridge 18205.05 Track Bar.

• Rugged Ridge 18006.54 Dropped Pitman Arm.

I thought about buying a new steering system, but that might have to wait until after winter, just cleaned up my current one. TRE's have no play in them.


So with all of that said here is the final result with some geo-lines marked up showing the effected angles.



So now heres the questions / opinions portion.
If I ditch the drop pitman arm, that should raise my drag link to a pretty close plane. (going to try this today and upload a new modified image)

As you can see my track bar isn't even with my axle (killing my OCD), but if I modify that or switch back to my old RE one, it will throw it more out of balance.


Any and all advice is welcome, but funds are pretty much nonexistent right now so keep that in mind.

Thanks!

ChrisOSX said:

So I'm going through and upgrading parts in preparations for another new york winter..yay...However now I have bad wander and bump steer. From my reading, the track bar and drag link have to be on the same plane, or as close to it as possible.

I have/had the Rubicon Express 4.5" Super Flex lift (RE6130). Was going through and replacing their known to fail POS bushings. But I decided to just replace some components.

So now heres the questions / opinions portion.
If I ditch the drop pitman arm, that should raise my drag link to a pretty close plane. (going to try this today and upload a new modified image)

As you can see my track bar isn't even with my axle (killing my OCD), but if I modify that or switch back to my old RE one, it will throw it more out of balance.

Click to expand...

at 4.5" of lift... your steering is not your limiting fact. lose the drop pitman arm and go back to a stock one. that should take care of 90% of your issues.

the trackbar doesnt have to be "level" the point to point relationship is the same no matter the shape. (but i know how you feel about things driving your OCD nuts, lol).

lastly... if you have wandering, check castor. with the 4.5" superflex kit, i was able to dial my castor back to about 6-6.5 degrees, and had zero wandering issues on 35s.

VAhasnoWAVES said:

at 4.5" of lift... your steering is not your limiting fact. lose the drop pitman arm and go back to a stock one. that should take care of 90% of your issues.

the trackbar doesnt have to be "level" the point to point relationship is the same no matter the shape. (but i know how you feel about things driving your OCD nuts, lol).

lastly... if you have wandering, check castor. with the 4.5" superflex kit, i was able to dial my castor back to about 6-6.5 degrees, and had zero wandering issues on 35s.

Click to expand...

Initially I got the drop pitman arm to hopefully relieve some of the steering stress and angle of the TRE's (seemed steep, but I think my boots were just too shot lol). Just looking at the pic in hindsight this is going to be my first step.

This is good to know about the track bar. I was always under the impression that the base would have to be somewhat level with the axle. but point a to point b mounting point stayed the same, so it makes sense that it shouldn't matter the shape of it.

Since putting on the lift in '05/'06 time frame, I have never had the castor checked or set, I remember wandering on real windy days but nothing really serious. From what I read the upper and lower ball joints should be in a vertical line? I think the upper sits slightly farther to the rear. So lengthening the upper control arms would rotate the axle to the front hopefully fixing the castor?

I currently have no way of reading angles, so it's going to be just having to eyeball it lol.

No. Looking from the side, if you drew a line connecting the upper and lower ball joint, the line should tip towards the rear about 6 degrees (upper behind lower). If it was 0 you'd have terrifying steering

trippled said:

No. Looking from the side, if you drew a line connecting the upper and lower ball joint, the line should tip towards the rear about 6 degrees (upper behind lower). If it was 0 you'd have terrifying steering

Click to expand...

Oohhh. Well all right then. It already appears to be trailing the lower. When I go out there later to do the pitman arm, I'll pull the wheel and post up what I got.

In addition to the new control arms. When I installed them, I based the length off of the RE ones so the specs should be the same.

Ok so I can't seem to edit my first post with some updated info, I guess I'll just have to reply.

Got side-tracked with some other things around the house, so I wasn't able to look at the caster.

However I did do the pitman arm, and just looking at the pic and a slight guesstimation as to the center of the joint at the top for the line, it looks damn good to me.

Haven't tested it out on a road that has a lot of bumps yet, but I'm driving it to work so thats the real test.

Good move on ditching the drop pitman - its not needed.

Your track bar / drag link relationship can't get any better than that with your setup, but honestly even the angles as shown in your first photo should not cause the problems you describe. It might make the handling a little worse but there are rigs with much worse angles that handle just fine.

Interested in hearing how it goes after your test drive.

Regardless of how the test drive turns out, I think it would be worth it to pay $39.95 or whatever it is now, and have an alignment done. Depending on the shop they might refuse to make any adjustments on aftermarket parts (look for a shop that will) but at the very least they will give you in writing what your caster, camber, and toe settings are. That can give you a baseline for making adjustments yourself and will make troubleshooting a heck of a lot easier. In fact, without it you are just taking stabs in the dark.

My guess is your caster and toe are off.

EricsXJ said:

Good move on ditching the drop pitman - its not needed.

Your track bar / drag link relationship can't get any better than that with your setup, but honestly even the angles as shown in your first photo should not cause the problems you describe. It might make the handling a little worse but there are rigs with much worse angles that handle just fine.

Interested in hearing how it goes after your test drive.

Regardless of how the test drive turns out, I think it would be worth it to pay $39.95 or whatever it is now, and have an alignment done. Depending on the shop they might refuse to make any adjustments on aftermarket parts (look for a shop that will) but at the very least they will give you in writing what your caster, camber, and toe settings are. That can give you a baseline for making adjustments yourself and will make troubleshooting a heck of a lot easier. In fact, without it you are just taking stabs in the dark.

My guess is your caster and toe are off.

Click to expand...

Yah I just had an alignment done the same day after I got my new tires put on, (I wish it was $40ish, after a coupon, $73.xx...ouch). Granted it was done at Pep-Boys, but I even talked to the tech who did it. He said that other than my drag link being bottomed out (to correct steering wheel alignment), my toe was good and within "spec". He didn't mention caster though, and like a dummy, I didn't ask for the result print out.

Not sure of any 4x4 shops around my area, but if my toe is good, I can adjust my steering wheel myself. Just have to get a angle/degree reader and see what my caster is. Yah its a stab in the dark, but this is something I never really messed with, and kinda curious about.

Alright so I got sidetracked with some life and other jeep stuff, (popping out upper rear shock bolts, new speedo sensor, un freezing my t-case from rust and figuring out the 4wd indicator light, sensor is bad need to replace). Now i'm back with an update and some more info and pictures.

As far as things go, everything that I have done so far has helped a lot, still have the wandering, which I think is attributed to my caster being off, I'll get into that in a bit.

But first. I can't edit my posts, and the image hosting site is killing my images as the "trial?" is ending, so I'm going to use Imgur. I will re post the images in this post as an update and also so a mod/staff can replace the images in the other two posts I have. I would appreciate it.

1st post image, (off balance):


6th post, (corrected alignment):


Now this is what I have as my caster, And a little confused to how far I should go back. Obviously 90 is straight up and down. And mentioned in another post here, the top ball joint should trail the bottom. I get that. But how far back is recommended for it to trail?

From what it looks like its at about 84 ( don't know what that translates in degrees. Also from the research I have done, and from the info here, I should be on the other side of that 90, like 85 or 86? No idea.

Anyways heres the image. It's measured by placing the angle finder on that flat spot nest to the diff.

84 on the diff gives you 3 degrees caster, I would try for more. Go a little at a time until you have driveshaft vibes then back off, it’s a balance you have to get to.

See the chart...

http://go.jeep-xj.info/HowtoAlignment.htm

Gotcha. But as mentioned. The top ball joint should be pointing more towards the rear correct? Yet in that article it states, "Top of diff should be tilting forwards. The more it tilts the less caster you have."

If the top of the diff points forward then the ball joint would be doing the same.

le man's terms:
- tilting the pinion up decreses caster.
- tilting the pinion down adds caster.



its an inverse relationship and you have to balance the two to attain what you feel is acceptable ride quality and handling.

furthermore... idk if i would trust that the diff cover is parallel to the Cs. measure caster off of the top BJ.

Yah finding the balance is probably the tough part. I'm just going to adjust to 86ish (mentioned in a few places I've searched) and go from there.

If anybody has any more input feel free. I'm going to be messing with this and a few other things in a couple days when I have some days off.

*thats also something I will do. I need to find a big enough piece of tubing to do so. Will do that before I touch anything.