Caster angle after lift. Still struggling with "floating"
 

So gonna get ya up to speed to my jeep from when I bought it two months ago to now.
2015 JK. Bought 50k miles looked in pretty good condition. Drove like a nightmare. Took it to local shop that "specializes" in RC lift kits. 35" tires were all jacked up tread wise. Put 33" KO2's on it. Had alignment done. Caster angle with the old tires and the new tires was 2.8 on the right and 2.6 on the left. PRETTY sure it just had a 2inch lift. Far as I could tell it was just shocks (zone offroad?) and coils as far as aftermarket. Shocks were so janked and rusted they had to cut out the old ones to fit the new ones. Anywho I ordered the 1.5" Teraflex suspension kit with the falcon 2.1 shocks. Shop tells me the install went great but they couldn't get the caster angles up to snuff.

So before I dropped my jeep off I told the guy that I did some research and the angle should be between 3.8-4 degrees. He looks at me like I just spoke chinese. He actually googles it while I'm standing there and goes "Oh look at that, they do recommend that angle." Cool, not feeling confident now. So we proceed and a day later I get my jeep back. They tell me the best they could do on the right was 3.7 and 3.1 on the left. He asked me if this thing was ever in an accident and well from the carfax there wasn't anything reported and well I didn't notice any structural damage before I got the thing from the dealer. It drives a helluva lot better now but still getting that floating while driving, generally at slower speeds like below 50. But sometimes at higher speeds if I'm on a shitty highway (I-95 for my east coast people).

COULD damage to a jeep prevent them from getting the proper caster? Is there something else that could be worn out that is causing this floating feeling? Should I just bite the bullet and install adjustable front lower control arms? Also I'm not even sure if I should be trying to shoot for a higher caster angle than 4 since it's only a 1.5" lift on 33" tires.

Tire change would not make the caster difference change unless ball joints were damaged. It would have to be a hell of an impact to affect the side to side caster angles that much as well. You may need an offset ball joint on one side to correct that difference. I run 6* positive caster on my 2.5" lift and she steers beautiful on smooth road and over undulations, bumps etc. Do you have adjustable control arms or geometry correction brackets on the front? If so you should be able to get the caster up to 4.8-5.5 + that way. With my lift (which is not that big compared to others) it was a little floaty at around 4.2+, not bad but is better now. The caster change for me took away the workload trying to make the Jeep go straight down the highway and the other huge improvement was the new adjustable rear TB and raise bracket.

Wow so I'm still pretty far off on what my angle should be, granted not as high as yours since I'm only running a 1.5" lift. I do not have adjustable arms. AS FAR as I know everything besides the 1'5" Teraflex kit I had installed is stock. Sometime tomorrow I'll get some pictures taken with what's down there, it's 1130pm and I'm at work currently so.

Check your tire pressure, you should be in the 24-30 psi range. Play around a little with the pressure to see if it makes a difference. What load rating on the tires? Jeeps are relitivly light and avoid E rated tires. Control arm reloctaion brackets, adjustable contro arms, or off set ball joints all can help correct your caster.

Since you do not have adjustable control arms nor control arm brackets, did they get the caster to whatever they could via cam bolts in the lower control arm brackets on the axle? Not sure how they got a difference of .2° side to side increased to .6° after their adjustments. It really sounds to me like you just need a better means of caster adjustment (control arm brackets or adjustable control arms) and possibly a cam bolt eliminator kit if you currently have cam bolts in it. Tire pressure and load rating makes a big difference too as Dirtman highlights.

No offense, but when a shop can't even tell you what the factory caster spec is, not sure you can really listen to much of anything they say. Also, 2.6-2.8° caster is more what we typically see with a 3.5"+ of lift. That doesn't mean the springs weren't 2" and just netted more actual lift, but that is pretty low caster; however, I find it harder to believe you netted that much more lift out of crappy RC springs, which really makes me question what else is installed on that jeep. You might snap some pictures of that front end and post them up for us.

My go to is hubs and bearings. Those wheels may be moving on their own. Stiff shocks help a lot. I would get variable and set them to an 8 for street driving and a 1 for offroading. Stiffness will really help. In fact, if the shocks are old, that might be the first place I start. Is one of those shocks bad or under performing? Next, I would see if you can get the tires/wheels to move in ways they are not supposed to.

Where did you get that Caster range? The factory spec I've always seen is
4.2* +/- .5* (so, 4.2 nominal, with a range of 3.7 - 4.7)

Don't worry about going over 4 degrees. Many of us prefer to be up around 5 after a lift.


Another vote for finding out exactly what is installed. Maybe there are spacers from a budget boost along with the 1.5" coils? As noted above, how did they adjust the Caster? (since it is non-adjustable from the factory...) Is there a rear trackbar bracket? (if so, does it drop from the frame or raise from the axle?) Is there a Drop Pitman and/or a front trackbar bracket, by any chance?

Okay so got some pictures for you all. I read all of your comments and so I'm not the most mechanically inclined though I've sure learned a lot since getting this jeep. As far as I'm aware there are no caster bolts, at least from what I could tell with my limited knowledge.
To answer some question I got that caster range from a previous post. I forget who it was but they mentioned stock is between 3.8 and 4 degrees. So I was just going with that as a starting off point. I was not aware that a lot of people go way over that. Keep in mind this is pretty much 75% meant for on road driving, work and back. And 25% just simple trails and getting into overlanding eventually. So right now, just cruising the town and highways.

So from what I was told by this shop it was just shocks and coils on it. I had a teraflex 1.5" lift with the falcon 2.1 shocks. Nothing else was added other than what comes with that kit, their ST1 package.

I have not checked my tire pressure yet. I need to run out to autozone and pick something up for that. As the area I live in doesn't really have anyway to test that.
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Back

Also I'm aware this thing is kind of a rust bucket. Personally it doesn't look TOO bad but I'm also not a mechanic lol.

One thing that stands out in the rear, you have a frame side drop bracket for that track bar. That isn’t ideal. It would be better to have a raised bracket on the axle side. Damn Rough Country :naw:. You might bend that driver’s side rear brake line so it’s not bending against that shock.

There’s not a clear picture of the lower control arm mounts up from to tell if there’s a cam bolt in there, but you report there is not (that you know of). If that is the case, the shop didn’t do diddly squat to adjust caster or “try to get it in range” cuz there is simply nothing they could do. It’s not adjustable with factory components. You have aftermarket BJs (grease zerk on top of the upper) which is a good sign, though can’t tell what brand.

TBH, I wouldn’t even trust what that shop told you the current caster is if they are telling you that you went from .2° to .6° cross caster simply by swapping those springs. You might try running by an actual alignment shop. They’ll scan your jeep and advise of current specs. There really isn’t anything they can do besides center your steering wheel and adjust toe, so you could at that point decline service and take your print out at no cost (except for your time). If you want to raise your caster, look at some control arm brackets ($100-150). They are an inexpensive and good option for you.