I installed a 4" pro-comp lift with a rear trackbar relocation bracket. the kit had no adjustable arms or trackbars, so my front end is shifted over to compensate for the static front trackbar.

i've replaced gears and driveshafts and now have vibes and jeep 'jumps' left and right when i hit bumps in the road.

heard replacing and adjusting rear upper control arms will set pinion angle correctly and help eliminate driveline vibes (ordered).

heard replacing and adjusting front trackbar will help set front end evenly (ordered).

any reason (like stopping the left right 'bump jump') in having adjustable -

A) front upper control arms?
B) front lower control arms?
C) lower rear control arms?
D) adjustable rear trackbar?

and any difference between JKSmfg, Full Traction, Tereflex, others, besides price?

 

I'm a novice, but I have done soooo much research the past month when it comes to JK suspension mods I dare to try to offer some advice. With a 4" lift I would definetly install a full set of control arms so you can really dial in your set for smooth driving on pavement and of course a nice amount of flex offroad. This sounds expensive, I know, but you have come this far trying to make your JK grow don't hold back now. And yes please make sure you get a front adj trackbar(Teraflex makes a MONSTER HD front trackbar)

When it comes down to which brand check the reviews and then decide. My control arms are the Rock Runners from Superlift. I went with these because they rotate and they are beefier. I'm sure you can't go wrong either brand.

By the way, your driveshafts, with your setup I would have put a 1350 in the rear. As a matter of fact I have 1350 front and back. I like to over build things

Good luck!

 

Go to this sticky by WOL:

https://www.jk-forum.com/forums/modified-jk-tech-2/modified-tech-faq-answers-questions-every-newbie-has-18617/

All the info you need is there. This is an excellent source of info with regards to modifying a JK.

Good luck

 

sounds like you are gonna deal with rear pinion angle and have adj front track bar on the way.I would highly recomend adding at least some front adj.control arms to get your caster set correctly.I have Teraflex lower front arms and tom woods 1310 front shaft and am running approx 6 degrees caster with no noticable vibration.I am sure if you get some more caster and recheck your toe-in(once your axel is properly centered with adj trackbar) should help with wobble.Note I am still running stock upper control arms and looks like bushings are gonna pop out when front fully flexed out,so gonna have to upgrade those as well.If I had to do it all over again I would just purchase all 4 sets of arms at once instead of piece by piece like I did

 

the bump jump you are feeling is most likely bumpsteer and that can be addressed with a dropped pitman arm and a front track bar drop bracket. this is of course in addition to an adjustable front track bar. lowering your draglink and track bar will help eliminate it. all the manufacturers listed are good companies to choose from.

 

thanks all for your help!!

so ...

rear upper control arms - will set pinion angle correctly and help eliminate driveline vibes (ordered).

front trackbar - will help set front end evenly (ordered).
trackbar relocation bracket (ordered)
pitman arm - to correct bumpsteer (ordered)

A) front upper control arms? - to get front pinion angle dialed in (ordered)
B) front lower control arms? - Dave @ northridge said not necessary
C) lower rear control arms? - Dave @ northridge said not necessary
D) adjustable rear trackbar? - not necessary if you install a relocation bracket

is the spending over???

 

Installed teraflex adjustable rear upper control arms. most of the vibration is gone.

at it's shortest setting, the teraflex arm is around an inch longer than stock arm, so the pinion angle could not be adjusted 'perfectly' and now slightly up.

guess an adjustable lower arm is necessary to dial it in perfectly? great - more $$$$$.

if i were to do it all over again would definitely have purchased a lift with adjustable everything! ordering pc by pc gets expensive.

 

I installed the Pro Comp Stage 1 lifft w/ MX-6 Shocks

Just an FYI... With the Pro Comp lift you will only get a tad over 3 inches in the front. Pro Comp is aware of this problem and admit that their 4" kit is only rated as a 3" kit. If you call them and inform you are not happy about the lift height they will send you a set of correct 4" front springs. May not be a big issue for you but you'll need the right height if you plan on running 37's!

Also to get back on topic, I ordered a JKS front adjustable trackbar and all my vibes and front centering issues are gone....

 

I put a 4 inch bds lift on my new rubi 2 door. Heres the situation. It came standard with fixed front up/low and adjustable rear up/low. I upgraded to the adjust front low but I cant use it because it ISNT EVEN CLOSE TO LINING UP THE BOLT HOLES TO FRAME! I put it away and put the stock lower front on it seems fine . Is it ok like to run stock control arms with a 4" lift. Why would you even want to buy new fixed control arms for the $ if the stock are fine...b/c they are 1/2 inch longer?? Im going to see if the alignment shop can figure out. what do yall think. ps I can upgrade front upper adjustable in order to use lower but y if fixed work ok.

 

i put the adjustables all around and set them to the length that the bds fixed 4" standard kit would be. Therefore now its set to four and have the option of going bigger later but moving arms longer. Its sits perfect with 35s I like the extra wheel well clearance. Pics will be up in a few once the painted parts are on. thanks.