2016 Jk all over the place - Caster help needed
#11
JK Jedi
here's the short and skinny response if it's hasn't been clear. take those brackets off and sell em....adjust the arms proper to get caster above 4.2* as you're being advised already, and get a raised TB bracket for the rear. that last part doesn't have to do with your steering, but you really want to raise that rear TB to help improve your roll center. That is separate issue than needing an adjustable rear TB to recenter the axle under the jeep. if 4WP is telling you that 2.8 - 3* caster is good and you shouldn't go any higher, they are fawking idiots and you should no longer deal with them.
#12
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There are two different things going on, that are directly connected:
As the pinion rotates down, caster goes up (better steering).
As the pinion rotates down, driveshaft joint angles get steeper. (possibly causing driveline vibes)
Can't change one without adversly affecting the other, it gets to be a trade-off between the two as you go higher.
So yes, you are correct that adj arms + brackets gives you plenty to work with to get the caster up to any number you want, as well as positioning the entire axle forward/backward in the wheel well. My guess is that the tech is looking only at driveline angle? But as noted by RK, you should be ok with caster up to 5* or so.
As the pinion rotates down, caster goes up (better steering).
As the pinion rotates down, driveshaft joint angles get steeper. (possibly causing driveline vibes)
Can't change one without adversly affecting the other, it gets to be a trade-off between the two as you go higher.
So yes, you are correct that adj arms + brackets gives you plenty to work with to get the caster up to any number you want, as well as positioning the entire axle forward/backward in the wheel well. My guess is that the tech is looking only at driveline angle? But as noted by RK, you should be ok with caster up to 5* or so.
if the drive shaft angel gets steeper cant you upgrade the drive shaft
#13
JK Jedi
Oddly enough, the aftermarket double cardan driveshafts are more sensitive to the steep angle than the factory repezza joint. There's a line at which the caster is too high and the result is driveline vibes. That said, they are fine in that 4-5* caster range. The factory DS will go in a matter of time at that height anyhow. You got 2 options. Leave caster low as it is and have shitty steering, or raise your caster to where the rest of us are and realize what the steering should feel like.
#14
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if the drive shaft angel gets steeper cant you upgrade the drive shaft
Get more comments about this: but my understanding is that the stock rzeppa joints are more forgiving with steep angles than aftermarket CV style shafts (as far as vibes are concerned). The problem with the stock joints is generally that the rubber boots get pinched, tear, then spit all the grease out. No grease for long enough, and the joint seizes.
Aftermarket double cardan shafts like to have the pinion pointed up at the tcase output. Hard to do if you need to lower the pinion to raise caster. Right? So it makes sense that these would be more suseptible to vibes from the caster/pinion trade-off.
So, as an option, if you find yourself with vibes after raising the caster, might be Terflex's high angle rzeppa replacement. No experience with it, but reviews seem favorable.
#15
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so tonight I was messing around with the jeep and decided to check the track bars
the front track bar is centered however the rear track bar is off centered - the passenger side is almost a inch shorter.
I don't know what effects this has on the handling.
I will get this fixed in the am and see what I can do about getting an alliugment at a different 4x4 shop that was recommended to me from my jeep club to fix the caster
I will also call terflex and order a rear track bar bracket
I do have a question for you guys - is it bad that I have mixed parts on my jeeps lift
rk springs
rx control arms
tf front and rear track bars
synergy tie rod and steering kits
rx front disconnects
I did also rfelize it looks like the rear sway connects were never upgraded
the front track bar is centered however the rear track bar is off centered - the passenger side is almost a inch shorter.
I don't know what effects this has on the handling.
I will get this fixed in the am and see what I can do about getting an alliugment at a different 4x4 shop that was recommended to me from my jeep club to fix the caster
I will also call terflex and order a rear track bar bracket
I do have a question for you guys - is it bad that I have mixed parts on my jeeps lift
rk springs
rx control arms
tf front and rear track bars
synergy tie rod and steering kits
rx front disconnects
I did also rfelize it looks like the rear sway connects were never upgraded
#16
JK Jedi
so tonight I was messing around with the jeep and decided to check the track bars
the front track bar is centered however the rear track bar is off centered - the passenger side is almost a inch shorter.
I don't know what effects this has on the handling.
I will get this fixed in the am and see what I can do about getting an alliugment at a different 4x4 shop that was recommended to me from my jeep club to fix the caster
I will also call terflex and order a rear track bar bracket
I do have a question for you guys - is it bad that I have mixed parts on my jeeps lift
rk springs
rx control arms
tf front and rear track bars
synergy tie rod and steering kits
rx front disconnects
I did also rfelize it looks like the rear sway connects were never upgraded
the front track bar is centered however the rear track bar is off centered - the passenger side is almost a inch shorter.
I don't know what effects this has on the handling.
I will get this fixed in the am and see what I can do about getting an alliugment at a different 4x4 shop that was recommended to me from my jeep club to fix the caster
I will also call terflex and order a rear track bar bracket
I do have a question for you guys - is it bad that I have mixed parts on my jeeps lift
rk springs
rx control arms
tf front and rear track bars
synergy tie rod and steering kits
rx front disconnects
I did also rfelize it looks like the rear sway connects were never upgraded
I'll reiterate what I said above. You really should have a raised rear TB bracket.....even if you have an adjustable rear TB. The idea is that raising the axle side mount will help improve the rollcenter and result in improved handling. the flatter the angle on that rear TB, the better off you are.
#17
JK Jedi
Raise the rear track bar on the axle as much as you can to get it as level as you can. The more level that link is the less axle shift you will have. Verify you have the axles in proper alignment with the body. Its easy to get off just a bit with the axle and they wont track down the road straight causing you to fight it with the steering. Once you verify that your axles are straight and centered get an alignment done and get a read out of what the numbers are. Going at it blind makes it hard to fix the underlying issue which like most have said is lack of caster.
#18
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Both swaybars should be roughly parallel to the ground. You don't need fancy links in the rear, just longer than stock.
#19
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Hi Guys
first off I want to thank you all for the good advice here...
Now for the updates
I went back to 4wheel parts and had them check the jeep over and do a new alignment (free of charge)
- they took off the correction brakets
- got a new alignment - specs below
front left
camber - o.6
caster - 3.4
toe - 0.05
sai - 3.8
included angle - 4.4
front right
camber - -2.7
caster - 4.0
toe - 0.06
sai - 24.3
included angle - 21.6
front
cross camber - 3.3
cross caster - -0.7
cross sai - -20.5
total toe - 0.11
left rear -
camber - -0.6
toe - 0.20
right rear
camber - -0.5
toe - 0.28
cross camber - -0.1
total toe - 0.48
threats angle - -0.04
from this all I understand is caster and it looks to be still low from what everyone has said it should be. how do all the other points look
I did order the rear track bar braket so when that comes in I will get that installed right away
after the visit to 4wp the jeep does drive a bit better in the wondering department still does but not as much. however now I have a bigger pull to the right.
my last resort if I have to is
I am thinking of replacing my 30 with terflex 44 front Axel along with a new complex RK 3.5 X factor kit or a terflex sport s t/3 kit and keep my current fox 2.0 res shocks - and basically start all over if I can't get this right soon....
if I do do a new kit are theses good kits for mostly street - highway driving as well as the weekend trails
first off I want to thank you all for the good advice here...
Now for the updates
I went back to 4wheel parts and had them check the jeep over and do a new alignment (free of charge)
- they took off the correction brakets
- got a new alignment - specs below
front left
camber - o.6
caster - 3.4
toe - 0.05
sai - 3.8
included angle - 4.4
front right
camber - -2.7
caster - 4.0
toe - 0.06
sai - 24.3
included angle - 21.6
front
cross camber - 3.3
cross caster - -0.7
cross sai - -20.5
total toe - 0.11
left rear -
camber - -0.6
toe - 0.20
right rear
camber - -0.5
toe - 0.28
cross camber - -0.1
total toe - 0.48
threats angle - -0.04
from this all I understand is caster and it looks to be still low from what everyone has said it should be. how do all the other points look
I did order the rear track bar braket so when that comes in I will get that installed right away
after the visit to 4wp the jeep does drive a bit better in the wondering department still does but not as much. however now I have a bigger pull to the right.
my last resort if I have to is
I am thinking of replacing my 30 with terflex 44 front Axel along with a new complex RK 3.5 X factor kit or a terflex sport s t/3 kit and keep my current fox 2.0 res shocks - and basically start all over if I can't get this right soon....
if I do do a new kit are theses good kits for mostly street - highway driving as well as the weekend trails
#20
JK Jedi
This is no knock on you for not doing your own work…..but I do think it makes the concepts harder to understand….and you get to the point that you just want it right and to drive nice at any cost, and I understand how/why that happens. There is no reason to go buy a new axle…..there is no reason to go buy a new lift. You have a full set of adjustable arms….or at least I believe you do. You can dial all this stuff in. Don’t believe that just because your axle only has 6* of caster built in that you can’t make this drive nice. You’re caster rose by taking the brackets off……now you need to adjust your arms properly to raise it even more.
This is not something that an alignment shop will do for you as part of a normal alignment. Understand that a normal alignment is just adjusting your toe, recentering your steering wheel, reading the specs, and handing you the paper. It is not making all the adjustments to give you a dream ride unless you are specifically paying them to make these adjustments.....and even then I wouldn't trust them without you knowing exactly what needs to be done and instructing them to do this or that.
You’re cross caster is .6*……and that seems pretty high to me. That means the C on the passenger side is tilted back a bit more than the C on the driver’s side. I would get that corrected and then reassess if it’s pulling one direction or the other before taking any more steps. If you can’t do it yourself……you should take it somewhere and ask them to readjust your control arms so that you’re achieving ~4.5* caster +/- .3* or so, and make sure your caster from left to right is within a couple tenths of a degree from side to side. You have to take a little ownership, at least understand what needs to be done to correct the issue, and tell someone specifically what you want them to do (if not doing it yourself).
Did you measure your arms on each side as suggested? Grab tape measure, get underneath it, and measure your arms…..both lowers, both uppers. If both the lower arms are the same length, it’s simply a matter of adjusting your upper arms to dial in the caster. I can’t say with 100% certainty this is going to remedy all your issue, but it’s the starting point. I suspect it will, but right now you’re specs are a bit wonky IMO, and you need to get that straightened out before you can get to the bottom of things.
Unless you’re just wanting a lighter wallet, spending thousands on a new axle and lift isn’t going to do much…..you still have to address the exact same geometry. A 3.5” lift is gonna end up costing you way more than you think when it’s all said and done. There are thousands of lifted jeeps on the road rollin' on factory axles. Outside of some extremely high build, there's no reason you can't get your jeep driving nice with your lift.
And to reiterate again, the rear TB bracket is needed and will improve your roll center, but don’t expect it to change any of this issue.
This is not something that an alignment shop will do for you as part of a normal alignment. Understand that a normal alignment is just adjusting your toe, recentering your steering wheel, reading the specs, and handing you the paper. It is not making all the adjustments to give you a dream ride unless you are specifically paying them to make these adjustments.....and even then I wouldn't trust them without you knowing exactly what needs to be done and instructing them to do this or that.
You’re cross caster is .6*……and that seems pretty high to me. That means the C on the passenger side is tilted back a bit more than the C on the driver’s side. I would get that corrected and then reassess if it’s pulling one direction or the other before taking any more steps. If you can’t do it yourself……you should take it somewhere and ask them to readjust your control arms so that you’re achieving ~4.5* caster +/- .3* or so, and make sure your caster from left to right is within a couple tenths of a degree from side to side. You have to take a little ownership, at least understand what needs to be done to correct the issue, and tell someone specifically what you want them to do (if not doing it yourself).
Did you measure your arms on each side as suggested? Grab tape measure, get underneath it, and measure your arms…..both lowers, both uppers. If both the lower arms are the same length, it’s simply a matter of adjusting your upper arms to dial in the caster. I can’t say with 100% certainty this is going to remedy all your issue, but it’s the starting point. I suspect it will, but right now you’re specs are a bit wonky IMO, and you need to get that straightened out before you can get to the bottom of things.
Unless you’re just wanting a lighter wallet, spending thousands on a new axle and lift isn’t going to do much…..you still have to address the exact same geometry. A 3.5” lift is gonna end up costing you way more than you think when it’s all said and done. There are thousands of lifted jeeps on the road rollin' on factory axles. Outside of some extremely high build, there's no reason you can't get your jeep driving nice with your lift.
And to reiterate again, the rear TB bracket is needed and will improve your roll center, but don’t expect it to change any of this issue.