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Discussion Starter · #1 ·
So here is a little background and my problem...

Back in May I put a 78/79 Ford Dana 60 under the front of my JK along with a 14 bolt rear. The wheels are Racelines with the steel rings. The tires are 40" MTRs. I also have a 3.5" RK lift and am running the Poly track bar frame side bracket and a Rock Solid track bar that came with my steering box stabilizer. I put 12 ounces of air soft bb's in the tires when I mounted them.

So I got it all together and I had noticed a bit of a shimmy at around 50mph. It wasn't bad, but pretty noticeable. Then, sometimes when I would hit a bump around 45mph it would go into what I call a "semi-death wobble". I say semi because if I were to slow down a few mph, like below 45, or speed up to over 50, it would cure itself. But it did have that same violent left right shake.

I read on Pirate that a common cause was not enough spring tension for the bigger tires on the kingpin. So I added some washers under the cap like people had said cured their problem.

I also had been told that 12oz of beads was too light for the tires. At this point my spare tire had not been mounted yet. So I put in the 17oz into that, put it on the driver side front. Took the driver side front tire off, put in 5oz more, and then moved that to passenger front. The passenger front is currently sitting in the garage.

I went for a drive to work and everything seemed ok. Until last night on my way home I was doing some higher speed driving and the problem has actually gotten worse. The Jeep is actually pretty much undriveable between ~45-50mph. Wobble still goes away when I slow down a little or speed up.

I know it's a pretty broad question..but any suggestions before I really start tearing stuff apart?

TIA
 

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Still sounds like a balance issue to me. I started with 7oz and went to 10oz. I'm starting to think I have too many and the beads are laying down/not bunching like they should. When things cool off ill probably start with 3-4oz or so.


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Discussion Starter · #3 ·
Still sounds like a balance issue to me. I started with 7oz and went to 10oz. I'm starting to think I have too many and the beads are laying down/not bunching like they should. When things cool off ill probably start with 3-4oz or so.


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3-4oz? wow

The guide said to do 12oz for a 40" tire. I tried that. Then went up...maybe going down is the plan?

It's really not THAT huge of a pain to pop the rear bead off. But then I was dumping in, not sure if getting them out will be easy. Maybe I can get my vacuum hose in there somehow.
 

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Discussion Starter · #5 ·
I have the same problem right now but between 35-40. I thought it was an unbalanced tire as well but after further investigation my drag link joints are shot.
Tie rod is brand new with the axle swap...but my drag link is the Poly one I bought last year for the D44. Just happened that length was damn near perfect.

I'll have to do some yankin around under there this weekend and see if I can feel anything loose. :lol:
 

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So here is a little background and my problem...

Back in May I put a 78/79 Ford Dana 60 under the front of my JK along with a 14 bolt rear. The wheels are Racelines with the steel rings. The tires are 40" MTRs. I also have a 3.5" RK lift and am running the Poly track bar frame side bracket and a Rock Solid track bar that came with my steering box stabilizer. I put 12 ounces of air soft bb's in the tires when I mounted them.

So I got it all together and I had noticed a bit of a shimmy at around 50mph. It wasn't bad, but pretty noticeable. Then, sometimes when I would hit a bump around 45mph it would go into what I call a "semi-death wobble". I say semi because if I were to slow down a few mph, like below 45, or speed up to over 50, it would cure itself. But it did have that same violent left right shake.

I read on Pirate that a common cause was not enough spring tension for the bigger tires on the kingpin. So I added some washers under the cap like people had said cured their problem.

I also had been told that 12oz of beads was too light for the tires. At this point my spare tire had not been mounted yet. So I put in the 17oz into that, put it on the driver side front. Took the driver side front tire off, put in 5oz more, and then moved that to passenger front. The passenger front is currently sitting in the garage.

I went for a drive to work and everything seemed ok. Until last night on my way home I was doing some higher speed driving and the problem has actually gotten worse. The Jeep is actually pretty much undriveable between ~45-50mph. Wobble still goes away when I slow down a little or speed up.

I know it's a pretty broad question..but any suggestions before I really start tearing stuff apart?

TIA
Are these new tires and wheels (new to the vehicle) that were installed after the axle swap or had you been running them on your old setup with no issue?

RK
 

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Discussion Starter · #8 ·
Are these new tires and wheels (new to the vehicle) that were installed after the axle swap or had you been running them on your old setup with no issue?

RK
The tires and wheels are new to the vehicle and also new to each other. But they were both used. Confusing eh?

I bought the tires mounted on some 5 lug bead locks, pulled them off the beadlocks and sold the bead locks. They had maybe 500 miles on them. I bought the racelines used and mounted them up.

The thing that confuses me is that swapping in the spare and going up a little in the BB weight actually made it worse.

It also seems as though the problem presents itself after the tires have warmed up a bit after a little driving. Could just be coincidence based on road conditions too.

I'm thinking the easiest thing to do first will be to swap the rears to the front and see if my problem changes at all along with checking all of my bolts and wear on joints.
 

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When the wobble starts, if you take a corner or switch lanes does it go away?

I had/have a similar problem with mine. It would go away if I turned or switched lanes in the speed range. I removed my steering box and reset the internal backlask per spec. It was WAY too loose. Made a night and day difference.

Unfortunatly for me, mine still persisted a little after that which I have since isolated to the unit bearings. It goes away once the bearing has heated up a bit and expanded (not hot to the touch however, just once it's warm). That would unrelated as you have hubs and lockouts I would assume?
 

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Discussion Starter · #10 ·
When the wobble starts, if you take a corner or switch lanes does it go away?

I had/have a similar problem with mine. It would go away if I turned or switched lanes in the speed range. I removed my steering box and reset the internal backlask per spec. It was WAY too loose. Made a night and day difference.

Unfortunatly for me, mine still persisted a little after that which I have since isolated to the unit bearings. It goes away once the bearing has heated up a bit and expanded (not hot to the touch however, just once it's warm). That would unrelated as you have hubs and lockouts I would assume?
I think if I took a corner at 45 I may have bigger issues... :lol:

I haven't tried changing lanes. I will try that though and see what happens.

Maybe I should check my hub bearings and make sure the spindle nuts are tight.

Thanks for all the ideas :)
 

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The guide said to do 12oz for a 40" tire. I tried that. Then went up...maybe going down is the plan?

It's really not THAT huge of a pain to pop the rear bead off. But then I was dumping in, not sure if getting them out will be easy. Maybe I can get my vacuum hose in there somehow.
You should take that chart and throw it out the window. It is the second biggest scam on the internet.

Have you done the steering wheel test? I thought this was pretty universal in the Jeep world.
 

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Discussion Starter · #14 ·
You should take that chart and throw it out the window. It is the second biggest scam on the internet.

Have you done the steering wheel test? I thought this was pretty universal in the Jeep world.
Maybe I'm missing something, what is the steering wheel test?
 

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Maybe I'm missing something, what is the steering wheel test?
You're missing quite a bit. It is a free tool that will let you find out what is loose in your front end so you can diagnose your wobble.

There is a great chance your wheel and tire combo isn't balanced properly and that is causing the start of your wobble when you hit that one speed. The steering wheel test is basically playing dukes of hazzard with your steering wheel while the Jeep is off and on flat solid ground.

Get someone to crank on the steering wheel from left to right. You want to move from 11-1 o'clock on the dial. Just enough to change the forces going through your steering system.

Get under there and look at all the components. Pretty good chance you will see the axle moving side to side under the frame. In a perfect world there would be zero movement side to side. A little bit during the steering wheel test is a crap ton at speed. So be specific about it.

Check out everything! Track bars, tie rods, rod ends, steering box, pitman arm.... everything!

You will find the cause of your wobble.
 

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