I have read dozens of Adjustable Control Arm threads and I'm trying to find an answer before making a purchase.

I've had my 07 JK for two years and when I got it had 2.5" Skyjacker Kit installed and with Cam Bolts. Months ago I welded up the cam bolt slots and have both sides set at +6 Degrees measured at the bottom of the axle. I had a death wobble for several months and in the past week I replaced the ball joints, the front track bar, and aligned the Jeep. The DW is gone but I'm still having a vibration from 45-65 and I think that it may be driveline vibration. I'm running stock drivelines front and back. I have balancing beads in the tires so it shouldn't be out of balance tires. I'm checking U-Joints tomorrow.

2 Questions. First, am I right that this could be driveline vibration since it is speed specific?
Second, I think I need to try less Caster, maybe 5 Degrees, if I got adjustable Lower Control Arms for the Front I know I can lengthen them for more Caster but can they be used to shorten and lessen Caster?

Thanks in advance!

RT

 

6 degrees positive caster sounds like a lot for a set of cam bolts. You should be able to get a set of front lower adjustables that at thier shortest, will be the length of your stockers. Pretty sure my Teraflex arms were factory length before any adjustment. Think factory spec is either 4 or 4.5 degrees positive..? There are upper arms that will adjust to shorter than the factory length to achieve the same result.

I would dump the front drive shaft before you do anything to make sure thats what your feeling. If the jeep is tracking well and drives nice, rule out as much as you can before you make any changes.

 

Give Adam a call at Clayton Offroad - I think their upper control arms have enough adjustment in them.

If you think your driveshaft is out of balance, take it to a local shop and have them checked/ balanced unless you plan on replacing them soom

 

I will pull the front shaft tomorrow to check if that's it. It is tracking well and drives nice other than the vibration.

So lower adjustable control arms are factory length at their shortest? If so I need uppers?


How do driveshafts get out of balance unless they've lost a weight or something? Tires get out of balance BC they lose rubber and weight etc but driveshafts don't lose or change do they? Confuses me.

 

Bump please.

 

Sir

We would recommend getting the measurement from a caster sweep off an alignment rack. But, if that is the case, most adjustable upper control arms will work for you!

Rock Krawler

 

I would think that it isn't a case of an out of balance front driveshaft but rather to much caster for the stock driveshaft. Like previously mentioned, get a caster reading from an alignment rack, pull your front driveshaft to see if that is your vibration and isolate the cause. Once you know where your caster is and where the vibration is from you can determine your most effective fix. as stated upper control arms will allow you to easily shift the top of the axle forward and reduce your caster.
I'm not sure of where you caster should be for a 2.5" kit but on my 4.5" kit we set it a positive 5.5 + which gave me great handling with no vibration. I also have an aftermarket front shaft with double carden joint.

 

Each set does different things. Planman says it best here. Get the set or sets you need. All 4 are not always needed. Hope it helps:

https://www.jk-forum.com/forums/show...=1#post1832861

 

it's likely caster is too high, as the angle gets greater the spinning rate at the u-joints is not equal and vibration occurs.

guess I mis-read the OP, just mentioned DS out of balance as something to check as well - DS do have weights on them, just not very often they fall off.

 

Thank you all for your help. I disconnected the front shaft at the Pinion and wired it up and out of the way (no need to pull it totally for testing purposes) and the vibration decreased a lot. I think I have a tire out of balance also, new 35's arrive today so we'll see if that helps too. The Jeep is getting regeared this week so the tires and rims will be waiting at the house on the Jeep to come home.

I think the problem is the front Pinion angle, I'm ordering the Rock Krawler uppers today from Northridge4x4 because the RK rep responsed to this thread they get my business . I'm loving there HD Tire Rod I installed last week!

I have replaced the following in the last 3 weeks to get rid of my DW but I'm left with this vibration.
Adjustable Trackbar (it is tightened to spec)
Ball Joints
Moog Drag Link end at Pitman Arm
Tie rod with Moog ends
Alignment

Question: Other than driveline and tire balance what else could be causing the vibration from 45-65 MPH? Trying to eliminate all I can.

Thanks again everyone!

RT