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Why UCA(Upper Control Arm)?

20K views 18 replies 12 participants last post by  Blackberry 
#1 ·
The other day I went to a wheel and alignment shop showed then the PML I have and I asked them what their thoughts werr on adding new calmini UCA's and how they are able to provide a proper front lift. What I was surprised to hear was they though I was crazy and did not recommend it or any lift, only by adjusting the tosion bars. They think that by adding new UCA will not provide addional lift. Are full of sh*t or not? What is the proper way of getting 3-4" of lift on the front? If calmini selld the kit,it should lift it up right? Could someone elighten on on this topic. Thanks
 
#2 ·
adding the uca on their own will do nothing other than give you new uca and ball joints. You have to adjust the torsion bars to raise the front up once you get the uca. The new control arms have a slightly different geometry that allows you to both lift the truck higher than you could with stock ones and still get an alignment after raising the front up.

As for how far your going to get the front, 3 inches is it, and maybe not that much. 3 inches is what they claim, but in reality you can raise it until you have .5 inch bumpstop gap, and that is with the stock bumpstops. Any more than that and your going to throw the front geometry off badly. You wont be able to get an alignment, you are pushing the cv joints beyond what they are designed for and will eventually destroy them.

So they are partially right in that you can only raise it through the torsion bars, but the uca allows you to crank the torsion bars more.
 
#4 ·
^^^^^what they said^^^^^^^

also, you will probably have to re index your torsion bars

(how to link in my signature below)
 
#6 ·
Low profile bump stops are nice for added wheel travel, but they aren't required for the lift.

I haven't seen anyone with a diff drop kit, though it would maintain the stock drive shaft angles...do you know where you can get one? I think most people have just left it in place and let the universal joints take care of the angles.

You really don't need stiffer torsion bars for a 3" lift though. It mainly depends on how badly you beat up your truck. Whether you lift you truck 0 inches, 1.5 inches, or 3 inches, your torsion bars are under the same load. If you are driving off drops or jumps and crashing down on your front suspension a lot...heavy duty torsion bars are nice...but the lift itself isn't need for stiffer torsion bars unless you just want them.
 
#7 ·
120K miles on my X, SLR UCA's, 33's, winch and winch bumper, and I've absolutely beat the ever loving s*** out of it on the trails. Still on the factory t-bars, CV's, and no diff. drop.

Am I saying don't bother with new t-bars? No. Just saying that they are not critical to have right from the start. I've planned for a while to get new/stiffer t-bars but my factory ones just keep putting up with the abuse. Once they finally give up the ghost, I'll either replace them or SAS.
 
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#8 ·
So I'm confused. Do you need new UCA's then when doing a PML to get a proper alignment? I've been reading about it and now I'm just really confused.
 
#9 ·
To add to what everyone else said- the control arms also provide more room to lift with respect to the bumpstop. If you think about it, with the PML you get pretty close to the upper bumpstop- you couldn't lift another 1.5" without crushing the bumpstops. I'm running at PML height and I had about 1/2" bumpstop gap. I installed control arms and re-indexed to get an additional ~1" of height, and I still have a good 1" bumpstop gap.

Also, on the tbars, I've seen just as many accounts of aftermarket bars breaking as stock ones.
 
#10 ·
So I'm confused. Do you need new UCA's then when doing a PML to get a proper alignment? I've been reading about it and now I'm just really confused.
No you do not. Only when you go to a 3" lift do you need the UCA's in order to get a proper alignment.

Some folks, Drake did and I did, installed UCA's when we did our PML's, or shortly after, because we knew we would be moving on to a 3" lift at some point.
 
#11 ·
So I'm confused. Do you need new UCA's then when doing a PML to get a proper alignment? I've been reading about it and now I'm just really confused.
Nope, you can go up ~1.5" with stock arms and get an alignment. To go from 1.5" to 3" you need the arms.
 
#12 ·
So I've been looking at upgrading the UCA to get the 3" lift in front. I've also been looking at the Calmini 3" SL kit but I'm not crazy about the shocks, I already have the shackles, and apparently the T bars are not crucial. I'm thinking about buying just the control arms, add a leaf, and either bils or rancho shocks then filling in the sway bar disconnects, upper ball joints etc once I replenish my bank account. Good idea or not?
 
#13 · (Edited)
Do you already have the PML installed?

It should be noted:

1) You don't need a "kit"...you don't need shocks right away...or torsion bars...piecing together and gradually filling in your suspension pieces is the right idea...so you are on the right track

2) The AAL will lift the rear about 3" on its own! It varies a bit by material properties and how much you have your truck loaded down and settling over time, etc...but the point being that if you have the AAL AND the PML shackles...your rear WILL be much higher than the front.

If you go the UCA route, there are 2 basic ways you can go:

1) UCAs in the front, AAL in the back, and REVOLVER shackles (pricey, but AWESOME) for the rear. Revolver shackles don't lift much (website claims 2", but people with them have said it is less), and increase the flexibility that is lost with the stiffer spring pack.

or

2) UCAs in the front, and the "adjustable shackle" in the rear. With UCAs in the front, the adjustable shackle is set to the maximum setting (2 1/8") This allows you to lift the front a little more than the rear...and level our your rake a little bit.


Also....just remove the rear sway bar...no need for it :) Link to the How To in my signautre :)

And...upper ball joints come with your UCAs
 
#14 ·
I did do the PML and thanks for all the info. That is just what I wanted to hear and I will look into the revolver and/or adjustable shackles as well. I did the real shackles pretty recently so I'm not over eager to buy another set but your reasons are definitely legitimate. Thanks again, I'm just starting to play with my X and all the info is very helpful.
 
#15 · (Edited)
I did do the PML and thanks for all the info. That is just what I wanted to hear and I will look into the revolver and/or adjustable shackles as well. I did the real shackles pretty recently so I'm not over eager to buy another set but your reasons are definitely legitimate. Thanks again, I'm just starting to play with my X and all the info is very helpful.
Yeah man I understand the feeling...the PML shackles are really only useful if you don't want to go any higher.

On a side note, it is theoretically possible to buy the 3 leaf add a leaf pack...and remove one or 2 etc....mix and match to try and get the correct ride height in the rear with the shackle and some of the leaves...but I don't know of anyone that has done that...so that could be tedious in and of itself to guess which ones would equal the correct ride height.

One other note if you do go the AAL route...get the 3 leaf pack. There is a single AAL that raises it 3"...it is cheaper...but the leaf will make the entire pack much stiffer. By spreading the stiffness into 3 leaves, the pack gets progressively stiffer and won't make the ride so harsh in the rear suspension. Any increased stiffness to the springs will reduce the flexibility of the rear axle...and that is where the revolvers come in. They are essentially a shackle with a rotating hinge in the middle. At ride height they are folded in on themselves...not adding much lift...but once the axle starts to flex they will unfold and twist, giving the axle more flexibility without fighting the springs as much. This is what MOST people seem to do on here...3 leaf AAL and revolvers.

I went with just a shackle on the rear because I didn't want to stiffen the rear springs at all. I bought the "adjustable shackle" which is longer than the regular PML shackle...and just set it at the highest setting and brought the front up the 3"...as far as I know, I am the only one running this right now... but I think a few others on here are considering it.


Revolver Shackles:

https://www.4x4parts.com/nissan/xterra-revolver-shackles-p-134.html

Adjustable Shackles:

https://www.4x4parts.com/nissan/xterra-adjustable-lift-shackles-p-5612.html


The revolver shackles give you some sick flexibility...but not much lift...so you have to have them along with leaf springs.

The adjustable shackle gives you a little more flex...but more lift....so you don't have to add the springs...and they are a lot cheaper.



ORRRR


Since you have just recently did the PML...you could go the 2" body lift route...cheaper and you can keep your PML shackles!
 
#16 · (Edited)
Ive got revolvers waiting to go on my truck, and im piecing together the lift as I decide what I want. Keep in mind with the revolvers though you'll need extended rear brake lines

One thing im gonna suggest about the shocks is if your leaning revolvers get the bilstein 5100s, I bought shocks for the truck when I 1st got it and have the 3 inch hds (4600s). Didnt quite think through where I was headed.

UCA's.... I want the calmini arms but everywhere I look, its saying extended backorder. so I may go ACs (undecided)

AAL- I been looking at xterror04's build thread and may go the route he went. prg deaver 2-leaf spring pack for a 2nd gen. minus the smallest leaf from a 2nd gen stock pack. should be around 2 inches

good luck :cool-big:
 
#17 ·
IMO, you don't need the UCA's for up to 2.5". Any franchise alignment shop will tell you they can't align it because of the liability with the alignment of the U joints and steering, which the UCA's take pressure off of by having a more direct alignment. I have done a 2-2.5" lift on my X with low pro bumpstops without the UCA's and have had no problem. Without lockers, your front differential does not have enough grab to break the U joint (as always, there are exceptions, but i have beat my truck to s*** for 205k and have no problems) and the main problem comes to your CV boot (manual lockers help this, but after 60k on my lift I have had no problems). I have clamini steering components and nissan automatic lockers. Take it to a smaller "ma and pa" style shop and they can align it properly by adjusting your rods--- just my $.02
Man, I don't wanna be that guy, but this is all wrong. The alignment issue has to do with dialing out the positive camber that results from lifting, not the CV angles or tie rod angles. In fact, the new arms don't affect those angles whatsoever, and if you go higher because of getting new arms, that'll actually make that situation worse. The u joints in the front prop shaft aren't affected either way- that's a solid connection between the transfer case and front diff.

All the new UCAs do is cock the upper ball joint at a different angle so you won't have camber issues.

I'm guessing you're getting yours aligned to factory specs? Those allow for a significant amount of positive camber. The specs for a lifted X call for zero camber.
 
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