Jeep Wrangler Forum banner

'14 Rubicon 3.5 RK lift caster numbers way low

15K views 44 replies 11 participants last post by  kjeeper10 
#1 ·
I just completed lifting my 500 mile 2014 Rubicon unlimited with a 3.5" X-Factor Rock Krawler lift. The caster numbers are really low. I know I can adjust them back to within specs but why were they even so low to start with? I followed the arm lengths exactly. Has anyone else had really low numbers to start with and had to correct them higher? I have mostly just heard people having high numbers and trying to bring them down. Right now the pinion, drive shaft and everything is pretty well in line as a diagonal but It is suppose to have a little angle to it I believe. How does everything else look? Thanks for your input.
 

Attachments

See less See more
1
#2 ·
How much actual lift did you end up with when you installed your lift? I'm guessing no winch, so maybe more than advertised? If so, that's where your caster went...

Sorry, I don't know the specifics of that lift, but I imagine someone will roll through that can offer you some specific advice...
 
#4 · (Edited)
Start with this http://www.wranglerforum.com/f202/jeep-jk-caster-and-lifting-502001.html

People need to understand that arm lengths listed are only a base or starting point. Different heights, heavy/light weight jeep. Factory mount locations are not always the same jeep to jeep.

When you have both sets of arms. Lowers set axle center in the wheel well. Uppers set caster pinion.

4.5 is a good stating point for caster. Here's what you do
- set lowers to 231/8
- use measuring technique discussed in my thread to set 4-4.5* caster.
Just note a alignment is the most accurate. Compare the caster number you got to the alignment machines number. Now you have a base to go by next time.
 
#7 ·
My post should get you very close.

The 231/8 number for lowers is common with all kits. The proper way to set them is to have the bump stop centered with the lower perch at full bump. (Like it would be stock)

Here's how It's done.

Match both lower arms at 231/8 and mount them up but don't tighten.

Next - find the best means possible to hold your pinion angle at + 2* (with that caster will be close to 4*)
Bolt in driver side upper to the frame. Then adjust out joint so the bolt slides through the hole in the axle mount,
(Snug both bolts but don't tighten)

Now bolt passenger upper up to the frame end. Then adjust joint out so the bolt slides through the axle end.
(Snug but don't tighten)

Note: The uppers may or may not be the same lengths. This will prevent any future bushing issues

Now that you have the arms all at length and pinion set. Tighten all jam nuts. Remove if you have to (remember lengths are set already)
Leave all bolts snug but not tight tightened.

Lastly, lower the jeep on its own weight. (Tires on)
And torque all to spec.
 
#8 ·
I used the AEV drop brackets (middle holes) with 3" Synergy coils. My caster is around 3.5/3.7 and it drives fine. I suppose using the lowest holes would get me to 4.5 but no idea what other problems that could cause. My eyes are having trouble seeing due to some eye drops but if I am reading your caster as 1.7, that is too too low.
 
#12 ·
Adjusted my lower control arms out 5 complete turns. Have about a quarter of an inch of threads showing now. Originally the measurement from RK had basically no threads. Did the small circle angle measuring from the small holes on the axle with my smart phone Measured right at 2 so my caster should be about 4. I know the bottom of the C's and top of ball joints are bad measuring points but they were agreeing for the most part with the other measurement +/-.5. Tomorrows alignment will show that. I can say that after the adjustment it drifts slightly to the left. Can't wait until everything is perfect
 
#13 ·
Good job man. Def post the alignment results.
It could vary a small amount. Just remember the difference for future adjustments.
Meaning, if you were shooting for 4 but got 5. Future adjustments should target 3 knowing the degree difference on a laser alignment machine.
 
#15 ·
Just leaving dealership. Caster is just a shy on the low side as 3.3 and 3.6 but I am going to leave it as is for now. I have the ATS fox stabilizer so it should help the track on the jeep. Camber is good and toe was off driving in to the dealership since I rotated the axle slightly for the camber. The only thing red is the cross camber and I don't see how that matters much.
 

Attachments

#17 ·
As I had posted a few weeks ago I had a second alignment done after I made some adjustments on the lower control arms and lengthened them 5 turns to increase the caster degree. Well I still didn't like the driveability with the mid 3 degree caster. I decided to made another adjustment and get a third alignment. First alignment was to see where I was. Second was to make adjustments and get it in spec. This time was purely for driving comfort. I shortened the upper control arms by 2 complete turns. I didn't want to add two more turns to the lowers since I had about a quarter inch of threads showing and the wheels look great in the center of the wheel well. Attached is my current alignment numbers. Both are in the mid to upper 4's on caster and it drives night and day better than mid 3's. Doesn't wander keeps straighter and the steering doesn't seem so figity. To anyone doing this lift set control arms to get in the 4*. I would say it drives every bit as good as stock maybe slightly better. I also have the Fox ATS so I am sure that helps too.
 

Attachments

#25 ·
Glad to hear you got it all squared away! These are the reasons we are trying to be more active on Wrangler forum. All of our measurements are starting points so sometimes you will have to adjust from there a little bit. 4.2-4.5 degrees is the factory caster spec that we shoot for. These specs should be absolutely fine to reach with a factory shaft at this lift height.

RK
 
#18 ·
BTW the reason for the before caster numbers being so high was because when I got it on the alignment rack I shortened the upper control arms 3 complete turns and didn't want it quite that high for my weak factory drive shaft/pinion angle. So I backed it out one turn and UCA is two turns shorter than my previous numbers.
 
#22 ·
Very helpful information. Same issue for me on my 2014 Rubi and 3.5 xfactor RK w/37's. There is a top notch alignment guy here in Phoenix AZ called Gary's Alignment and Brake. This dude knows what he's doing and didn't even charge me to find the problem that 4Wheel Drive and Total Auto Pros could NOT find.

I'm purchasing the 1 degree Rabestos offset for upper passenger here. More Information for RAYBESTOS 6154001

Once installed I'll take back to Gary's for what I expect to be a perfect alignment.

I have sleeved axles and welded gusset supports. I haven't done anything so radical to cause any type of bending or damage. I suspect the angle of the pinion is at least one cause of the offset issue along with perhaps numerous other slight variables in lift installation and factory spec variation.
 
#23 ·
Very helpful information. Same issue for me on my 2014 Rubi and 3.5 xfactor RK w/37's. There is a top notch alignment guy here in Phoenix AZ called Gary's Alignment and Brake. This dude knows what he's doing and didn't even charge me to find the problem that 4Wheel Drive and Total Auto Pros could NOT find. I'm purchasing the 1 degree Rabestos offset for upper passenger here. More Information for RAYBESTOS 6154001 Once installed I'll take back to Gary's for what I expect to be a perfect alignment. I have sleeved axles and welded gusset supports. I haven't done anything so radical to cause any type of bending or damage. I suspect the angle of the pinion is at least one cause of the offset issue along with perhaps numerous other slight variables in lift installation and factory spec variation.
What is your problem, caster or camber ?
Off set ball joints are typically used for camber issues. In one case, I know a guy who uses upper and lower off set joints to dial in caster lifted higher.
 
#27 ·
I have the same exact issue (2014 JKUR with 3.5” X-Factor Kit). Just has an alignment and my caster is at 1.7 on both sides.I asked the shop about it and they said that they drove it and it drove great so they didn’t adjust the caster any.And the thing is, it really doesn’t drive bad – tracks straight, doesn’t seem too flighty, etc.If I keep it the way it is, is this causing any unneccassary stress on anything else?Would I see a big difference if I adjust the caster do around 4…?Thanks everyone…
 
#29 ·
They drive so much nicer at high 3 and low 4 at 3.5" lift... And it's so easy to do. Set the lowers at 23-1/8 and the uppers around 18-13/16 and see what your caster looks like using an angle app on the pinion. Why spend the money for a premium lift to not have it set up correctly?
 
#30 ·
If it's that easy, why do the RK instructions specifically say to set the front uppers at 19 3/8"...? That seems like a pretty large difference of a starting point. And I understand that they are reference numbers only and not all are the same, etc...

I guess I need to adjust them and see if it increases the drive quality. I just don't have access to keep going back and checking the angles without paying each time...
 
#33 ·
#31 ·
Guys, the issue with RK's (Previous) gen arms is they are too long, specifically the uppers (min 19 1/8) so you can not set normal arm numbers.
That and IF the installer followed RK's #'s caster is in the 2's.
I knew this before install and set my uppers to min and lowers around 1/4 longer.
Even then my caster came in at 3.5°

RK's new 2016 arms will adjust stock. I do not know what the instructions say for lengths.

Currently i would use the numbers PSI mentioned , somewhere around 23 1/4 lowers, stock 18.75 uppers.

If you have the previous arms, all you can do is either set the uppers to min, lengthen the lowers or adjust both to achieve 4.5-5°
 
#37 ·
Guys, the issue with RK's (Previous) gen arms is they are too long, specifically the uppers (min 19 1/8) so you can not set normal arm numbers. That and IF the installer followed RK's #'s caster is in the 2's. I knew this before install and set my uppers to min and lowers around 1/4 longer. Even then my caster came in at 3.5° RK's new 2016 arms will adjust stock. I do not know what the instructions say for lengths. Currently i would use the numbers PSI mentioned , somewhere around 23 1/4 lowers, stock 18.75 uppers. If you have the previous arms, all you can do is either set the uppers to min, lengthen the lowers or adjust both to achieve 4.5-5°
^^^^ :whistling:

I went through all that with RK's arms. Like i said 23 1/8 (common lower setting) is too short with RK's uppers. You are going to have to bring the lowers out to 23 1/4 - 23 5/8 to get caster around 4°
 
#35 ·
Thanks pressurized - I will read through these... Here are my numbers currently (JKU)
Perfect, there is a flat spot on the front of the axle that you can use to set your baseline. Even if it measures 2deg, you just want to add 2 to 2.5 since we know your real baseline is 1.6.
 
#38 · (Edited)
For anybody reading this and picked up a new RK x-factor lift kit. The new arms all but rear lowers adjust to stock. I dont know what RK uses for settings -if they changed. For front lowers i would start at 23 1/8 (2.5 lift) and 23 1/4 (3.5 lift) Uppers should end up close to stock
edit: also the front uppers are double adjustable meaning adjustments can be made on the JK
 
#40 ·
Who did you order from ? I bet some venders still have older stock. The new kits also come with a rear bolt on track bar bracket.

Hmmm mine are set to 23 5/8 and my sb link is no where close to hitting the coil. My issue was coil/Synergy TB brace clearance. I was maybe 1/8 from touching before installing Synergy uppers.
What angle is your SB at?
 
#42 ·
I don't think it is my vendor - I ordered with Marcus at RCO and he is awesome. Plus, I think they are shipped from RK anyway. He's helping me out with this too on his end. Great guy.

If I push the lowers out, what other issues might there be? Will I be causing any other issues?

The SB is pretty close to being dead level.
 
#45 ·
I don't think it is my vendor - I ordered with Marcus at RCO and he is awesome. Plus, I think they are shipped from RK anyway. He's helping me out with this too on his end. Great guy. If I push the lowers out, what other issues might there be? Will I be causing any other issues? The SB is pretty close to being dead level.
I would bring it up to +5 or +10°

No at your height 23 1/4-5/8 will not be a issue.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top