Talon1

So, pretty new to the JK world here. I've got a 2016 JKU with pro comp shocks, pro comp 2.5 lift and BF Goodrich M/T 35's. I obviously picked this rig up used so I'm not 100% on what I'm working with.

My issue is that I feel a lot of side to side movement over about 45mph. I've researched this and understand that it is common for JK's to drift around a bit. My question is if I could get some input from you guys on things that may help to reduce some of this movement.

Thanks

Sixty4x4

Side to side tells me that there are trackbar issues. Are the TB's got any rise on them? They have a lot of ass wobble going over bumps and undulations without geometry correction. Mine did with 2.5" lift also until I corrected. Also your diffs may be out of center with a lift and no TB corrections like adjustable length and the raised brackets I mentioned.

Talon1

Thanks Sixty. I'll check on the TB's and the other geometry involved.

Sixty4x4

Also forgot to ask if it has caster correction either in the form of LCA brackets or replacement adjustable lowers at least? I use lowers front and rear as that technically pushes the diffs further apart. Will add adjustable uppers soon Your caster should be at least in the +4.8 Deg range. All these little things add up to a world of difference collectively.

Talon1

Thanks for all the info. It's given me a great place to start my research.

resharp001

Having started on a cheap Pro Comp lift back in the day, I'd suggest you're not working with a whole lot there. Those same shocks didn't last me very long, and the TB that Pro Comp used to use was pretty junky with a poly bushing on the frame side. IDK if they've updated that at all but it's definitely low-end stuff. I don't say that to be mean, but so you can be realistic about what you're working with and can possibly think about some upgrades along the way rather than trying to make what you have work or continue building around it. Springs are springs, and unless they're sagging those are fine, but shocks change a ride dramatically and that front TB is one of the most important components on the vehicle. A high-quality TB is well worth having as a high percentage of wobbles emanate from crapped-out TB joints. Metalcloaks TB cost ~$200 and is a great piece. There are obviously a lot of others out there but if you look at TBs pay attention to the joints each use.

If a 2.5" Pro Comp lift has any caster correction, it is likely cam bolts in the axle's lower control arm mounts. Look to see if that is a normal bolt or a cam bolt holding those LCA's.

Talon1

Dude, JK Jedi, fantastic info. That gave me enough insight to be able to start in a solid direction on this rig. I really really appreciate the info.

resharp001

There are a lot of jeeps out there rolling around on cheap lifts because previous owners didn't know any better and that is what shops like 4WP often push due to the attractive prices for people to achieve the "jeep look" they want. Unfortunately those lifts are bare-bones type things with inferior parts. The jeeps then move on to new owners over time and when you buy a modified jeep half the battle is figuring out what was or was not previously done. SOOOO, the good news is you have a great vehicle in that JK which will likely provide a great smiles per mile return on your investment. The bad news is you'll likely need to invest a bit more to freshen things up and improve the ride quality.

Caster correction is a big thing on a lifted jeep. Caster is 4.2° from the factory, and when you lift that decreases. On a 2.5" lift you're probably around 3° caster (just ballparking). Small changes in that caster angle translate to big differences in quality of steering. You'd really like caster to be up over 4° again, but there is no way to adjust caster on these from the factory. This is what Sixty4x4 is getting into above. There are a few ways to raise caster back up, some better than others. Cam bolts are cheap and what a lot of cheap lifts use, but they are a terrible option IMO. Control arm brackets are inexpensive ($90-160 range depending on design) and are a great option, though you lose some ground clearance at the frame rails which is not ideal if you like to play in big rocks. These brackets do however provide great pavement ride quality as they really level out the angles of the control arms. You can also correct caster with adjustable control arms, either a full set or can get by with just front lowers. They have longer fixed control arms on the market as well but these are not a great option IMO.

Kinda long-winded and can't say for certain your issue is this or that at the moment, but at least a starting point for you.

Talon1

JK Jedi, thank you again for all of your information. Super valuable. Metalcloak is just down the hill from me so, I'll pick up their TB.

I just went out and measured from the top of the spring housing to the end of the tire and its unequal. So I've got another issue to figure out as well now.

resharp001

I wish I was as knowledgeable as my post count is high........unfortunately my knowledge is an accumulation of all my mistakes along the way.....with the JK and with life in general! .