NAUTIQUE

I have a new-to-me 2016 JKU Sport.

I swapped the P255/75R17's with Rubicon JL BF Goodrich All Terrain T/A KO2 285/70/17's (33").
& added Quadratec's Maximum Duty 1.75" Front / .75" Rear Leveling Lift Kit.

From everything I had read, this was a pretty straight forward upgrade, without any additional suspension mods needed.
I had an alignment done yesterday & they recommended that "Caster Kits" be added?

It seems to be riding great, but does anyone know if anything additional is actually needed, & if so, what benefit it would add?


Rubi 33's

LC Boyer

Nice looking wheels. I’m not sure what a caster kit is, or what it will do to a straight axle.

karls10jk

You don't need caster correction at that height. Most of the brackets won't work for you because of the low lift height. You could do adjustable arms but that's pretty well putting the carriage in front of the horse at this height.

resharp001

I'd bet dollars to donuts they are suggesting cam bolts given the modest lift height. You don't need anything really, and you should refuse cam bolts should anyone try to install them on your axle.


Since you added JL tires......I've been curious, is everyone just cranking those lug nuts down securely and not noticing any ill side effects from the change in wheel studs (1.2" on JK to 9/16" on JL)?? I guess just that much more important to make sure lug nuts have proper torque so there's no play between the wheel stud and the wheel itself?

smshield28

I just put the exact same wheels and size on my 2012 JKU and have had not problems. I've got about 3k miles on them so far and work at treat.

I was warned on here about possible issues with the lug diameter being different but so far so good. Nothing has come loose and no vibrations or other noticeable issues I can find.

nthinuf

Caster is tied to the 'rotation' of that front axle. When a suspension lift is added, the entire axle rotates, with the pinion pointing further up than it was. As the pinion moves up, the Caster goes down, it's automatic. As lift height increases, the pinion rotates progressively higher, and the Caster number gets progressively lower. (the alignment printout should show the 'stock' range - and where you are currently, likely printed in red since it is low...)

So all the alignment shop is telling you is that, due to the lift, your caster is now lower than the factory spec.

At shorter lift heights, the lower caster isn't usually enough to worry about - as others are already sayng. (and you indicate that it still rides great...) But, as lift height goes up and Caster keeps going down, it causes progressively flightier steering. At some point, (which can vary a lot due to personal opinion), a person will want to correct that flighty steering. (2.5"-3" seems to be where most choose to start addressing it.) To do that, there are several options for raising the Caster back up, each one having its own pro's and con's. Basically they are just different ways of rotating the axle the other way by a certain amount, which lowers the pinion and raises the caster again. Pretty easy stuff when you put it in context.

NAUTIQUE

Thanks for the feedback so far guys!
It looks like the print out shows Caster at 3.1 deg.left front & 3.2 deg.right front. This was the same before & after measurements.
From what I'm hearing on various forums, the consensus seems to be it should be fine with the small amount of lift.
I just don't want it to be tearing up the tires or have handling probs.

nthinuf

Yep, no way for them to raise it back up to stock spec unless you elected to have more parts installed. If you are happy with the steering, leave it alone.

But, if you decide that it actually 'is' more flighty (tends to wander around more than it did), you can post about the options and wade through all the opinions of what is best.

NAUTIQUE

Thanks for the info nthinuf!
In your opinion, what is the simplest fix if I do find it wandering too much?

nthinuf

Simplest? They all take a little work.

Cams - remove the bolt in the lower arm at the axle, drill out the hole in that bracket, install the cam, bolt arm to the Cam. Do the other side.
Brackets - remove the bolts in both upper and lower arms at the frame, install the bracket, bolt arms to the new bracket. Do the other side.
Fixed arms - remove an arm, replace that arm. Do the other side.
Adjustable arms - same as fixed, but you can adjust them to get the caster exactly where you want it - instead of where ever it ends up.



I'm bored, so here's a little more info (and some opinion) on the options also:

Cheapest? Lowest to highest cost is the same order. Cams , Brackets, Fixed, Adjustable.

Best? Debatable, depending on budget and use. (But, Brackets or Adjustable arms.)

Cams - You have to drill out the holes in the brackets. If you choose to move to another form of caster correction, what about those larger holes? And, with offroad use, they have been known to slip and put the caster back where it started. Onroad, probably not an issue. (I've never used them, so maybe not an issue offroad either, just regurgitating what has been reported...)

Brackets - In addition to caster correction, they also have the added benefit of lessening the steeper post-lift angles on the arms.
But, brackets have fixed holes corresponding to certain lift heights. Generally either a single hole (2.5"), or three options on the same bracket (2.5"/3.5"/4.5"). In your case with a 2" lift, there is no 2" hole, so instead of moving back to stock caster, the minimum height moves your caster from 'lower than stock' to 'a bit higher than stock'. (at 2", this is not a bad thing. Taller lift heights is where too much positive caster might become an issue.)

Fixed arms - the downside, they are fixed. Like the holes in the brackets, you move from one caster setting directly to another, and you won't know where you end up until you put them on. A plus is that, in addition to raising the caster, there are various types of joints to choose from, and some are bent at different angles to help with clearance.

Adjustable - Downside is the highest cost of the various options. But, you get to choose the joint, the bends, and can't complain about putting the caster exactly where you want it.