vibration at 60-65

Jk4lfe

Jk4lfe

New member
I just installed a synergy tie rod, drag link flip, and a track bar relocation bracket. All the usual symtoms were there, I.E: off center steering wheel, tow issues ect. I developed a audible POPPING noise after adjusting the track bar to re center the axle... not sure what it is. I installed a 3.5 inch rubicon express super flex kit, did not come with a rear adj track bar, one is on order. My rear axle has shifted to the drivers side. I just took my jeep to a very reputable alignment shop, which I have used in the past. They called me this morning and said the caster, tow, camber and thrust were off. They did what they could (couldnt fix the thrust), and I picked it up, after they were closed. The jeep now shakes at 60-65...never done this before at all....blown mind at what it could be....:grayno:
 
What did they do? Did they give you the alignment sheet with before and after readings? Too much caster can give you driveline vibes. Can't do anything with camber without major work. Larger tires may not like stock toe specs.
 
no, they didnt give me a sheet, looks to me like they didnt even touch the caster from the stains on my control arms nothing looks disturbed... but the rear is pushed out to the right and the thrust angles are all wrong
 
Usually when it shakes only at a certain speed it's a tire needs balancing. Maybe a weight got knocked off. Check each wheel for a missing weight
 
mds22 said:
Usually when it shakes only at a certain speed it's a tire needs balancing. Maybe a weight got knocked off. Check each wheel for a missing weight
Click to expand...

I agree I have a set of wore out tires for the street, and one is a little out of round so it gets a slight variation.
 
Thank you for the replies, I will check today for the weights missing, but could it be that the rear is pushed out to the drivers side that causes some vibrations...keep in mind this isnt death wobble
 
Unless you have some cam type ball joints, there is nothing that can be done for camber. Two things effect thrust angle, rear axle position and arm length. If your axle is drastically shifted to one side correct that first and then remeasure arm lengths (assuming you have adjustable arms). Thrust is absolutely correctable, but you may need some additional parts (like a raised rear track-bar bracket).

Shimmy at a certain speed is usually tire balance related. I have found that the stock toe angle is a bit low for larger tires. Follow Eddie's alignment write up (I'll edit soon to include a link) and set the toe to a gnat's ass under an 1/8" for 35s and at 1/8" for 37s.

It could just be that the tires are rolling straight down the road now and slight balance issues are more noticeable. :thinking:


Edit, as promised -> http://wayalife.com/showthread.php?3861-Basic-Do-it-Yourself-Jeep-JK-Wrangler-Front-End-Alignment
 
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Jk4lfe said:
Thank you for the replies, I will check today for the weights missing, but could it be that the rear is pushed out to the drivers side that causes some vibrations...keep in mind this isnt death wobble
Click to expand...

No this shouldn't cause a vibration. Are you sure the axle is shifted out on the drivers side? I ask because normally a lift will pull the axle to the passenger side of the Jeep. Raising the axle mount flattens the track bar and re-centers (or gets it close enough). If you are too far to the driver side I'd like a picture of the rear suspension to have a look-see.
 
I have a raised track bar bracket on the rear, with a stock rear track bar, the upper control arms are the only adjustable arms (both front and rear) and its out a good bit to the drivers side...

For the other things, I have synergy ball joints so I guess my axle came with more neg camber than usual, I have it towed in approx 1/8" with 35's

I will post a pic of it when I get a chance, bare with me for a little bit im in a glorious military school haha:sigh:
 
I'm not able to tell anything about the rear suspension from that picture, but I do see you have some poor tire wear and fairly extensive cupping on the inside of the driver's rear tire. You might be dealing with a tire issue now from poor wear.

edit... it could just be lighting angle, but it looks like cupping to me
 
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Jk4lfe said:
What kind of pic do you need? Im free for a bit, look at the drivers rear sway bar link
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You can't always tell axle shift from the sway links as the sway bar moves side-to-side too easily. I was wanting to get a better look at the springs and trac-bar.
 
Ok give me a few and ill get you one, you can stand behind and in front of the jeep and see its shifted too
 
It does.

You need to either run the drop bracket you have on the frame OR the raised bracket you have on the axle, not both. If I had to choose I would keep the axle bracket.

Your track bar is too flat and is pushing the axle too far to the driver side as a result. You also likely have a bit of roll-bump when in s-curves.
 
I will add though that I highly doubt this is the source of your vibration and I even doubt this is enough to push the thrust angle out very far. None-the-less, it should help handling and will pull the axle more center.
 
Its got the thrust out pretty good, id say an inch or more pushed to the drivers side, thank you very much for the help, i have an adjustable rear track bar coming, but will pull the drop bracket off, i feel like such a NOOB because i didnt catch it putting in the lift
 
Jk4lfe said:
Its got the thrust out pretty good, id say an inch or more pushed to the drivers side, thank you very much for the help, i have an adjustable rear track bar coming, but will pull the drop bracket off, i feel like such a NOOB because i didnt catch it putting in the lift
Click to expand...

Happy to help. I'd bet removing the bracket will pull it in what you need. It's not that big of a deal to have the axle off a little bit. Even small weight changes like a full tank of gas or you being in it will cause to to move some. Just because it's off doesn't mean the thrust angle is. Thrust angle is more commonly caused by the arm lengths being wrong, bent or damaged arms, bent frame, damaged arm mounts. or bent axle housing.

I wish I was able to help you more with your post issue (vibration)
 
Now i need to find my loud popping noise thats happing after the flip kit, and tie rod relocation bracket
 
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