Adjustable or Fixed Lower Control Arms?

[mschlott]

I Installed a 2.5 inch spacer lift last month and I'm happy with what I got for the price. I love the clearance that I got and the ride is acceptable. What I'm not happy with is the shaking that happens when I hit bumps. I only have 4K on my jeep so it does not devolve into death wobble, but I know it is not going to get better over time.

I'm planning on getting new control arms to get the caster back into spec. I'm trying to decide whether I need to get adjustable control arms or just longer control arms. I'm a little concerned about weak points in adjustable arms given that I do some rock crawling and put a lot of pressure in unexpected directions on the suspension.

Is weakness a concern for adjustable lower control arms? For fixed lower control arms what should I be looking for with a 2.5 inch lift on a JLUR?

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[oceanblue2019]

I'd buy a set of Rock Jock, Metal Cloak, Rock Krawler, or Synergy lower adjustable, set them to 24.5" starting length and give it a go.

The problem with most fixed length is they use the same factory bushings which will slop out and cause problems especially if you off road it.

 

[limeade]

I'd buy a set of Rock Jock, Metal Cloak, Rock Krawler, or Synergy lower adjustable, set them to 24.5" starting length and give it a go.

The problem with most fixed length is they use the same factory bushings which will slop out and cause problems especially if you off road it.

I agree with this.....mostly.
Rock Krawler offers their Adventure Series fixed lower control arms for a 2.5" lift (as spec'd on a Rubicon). These arms feature the same joints as in their adjustable arms, but at a slightly cheaper price. If you know you won't be adding any lift or have a need to adjust caster any more than what these arms offer, then they are a great alternative to adjustable arms.

 

[mschlott]

I agree with this.....mostly.
Rock Krawler offers their Adventure Series fixed lower control arms for a 2.5" lift (as spec'd on a Rubicon). These arms feature the same joints as in their adjustable arms, but at a slightly cheaper price. If you know you won't be adding any lift or have a need to adjust caster any more than what these arms offer, then they are a great alternative to adjustable arms.

It does not look like Rock Krawler offers a front lower control arm as a stand alone product. They only show the entire front and rear, upper and lower kit on their site. Is it common to only replace the lower control arm?

 

[rickinAZ]

I'm assuming that you've seen this:
https://www.jlwranglerforums.com/forum/threads/mopar-lca-swap.22474/

I'm in your same situation, and have the Mopar LCAs on order. For $61 delivered, it's easy to justify trying these first, even if you ultimately end up going with the adjustable LCAs.

Plus...in our situation, the extra .25" is likely all we need.

 

[limeade]

It does not look like Rock Krawler offers a front lower control arm as a stand alone product. They only show the entire front and rear, upper and lower kit on their site. Is it common to only replace the lower control arm?

On the Northridge 4x4 site, the arms are offered.

Adventure Series front LCA's are $254.18
https://www.northridge4x4.com/part/...ock-krawler-adventure-series-front-lower-arms

The X Factor front LCA's are $392.08
https://www.northridge4x4.com/part/...ock-krawler-x-series-front-lower-control-arms

With the 2.5" lift, either of these will get your caster around 6.5*. The Adventure Series just gets your there about $140 cheaper and no jam nuts to tighten.

 

[limeade]

I'm assuming that you've seen this:
https://www.jlwranglerforums.com/forum/threads/mopar-lca-swap.22474/

I'm in your same situation, and have the Mopar LCAs on order. For $61 delivered, it's easy to justify trying these first, even if you ultimately end up going with the adjustable LCAs.

Plus...in our situation, the extra .25" is likely all we need.

The Mopar lift LCA's are great if you've got a stock Rubicon. Once you add lift, you'll be at a caster deficit again.

Those Mopar arms should be stock on the Rubicon's, but for $60 they are a cheap upgrade to get the caster where it should've been from the factory.

 

[rickinAZ]

The Mopar lift LCA's are great if you've got a stock Rubicon. Once you add lift, you'll be at a caster deficit again.

Those Mopar arms should be stock on the Rubicon's, but for $60 they are a cheap upgrade to get the caster where it should've been from the factory.

Can't disagree with your logic. In my case, I have a short leveling lift and 5 degrees of caster. The Mopar LCAs should get me to 6 degrees. Do you think that 6 degrees isn't enough for on road driving?

 

[mschlott]

I'm assuming that you've seen this:
https://www.jlwranglerforums.com/forum/threads/mopar-lca-swap.22474/

I'm in your same situation, and have the Mopar LCAs on order. For $61 delivered, it's easy to justify trying these first, even if you ultimately end up going with the adjustable LCAs.

Plus...in our situation, the extra .25" is likely all we need.

No, but I'm reading that now. Trying to find the end results. Let me know how the install goes.

 

[oceanblue2019]

I'm assuming that you've seen this:
https://www.jlwranglerforums.com/forum/threads/mopar-lca-swap.22474/

I'm in your same situation, and have the Mopar LCAs on order. For $61 delivered, it's easy to justify trying these first, even if you ultimately end up going with the adjustable LCAs.

Plus...in our situation, the extra .25" is likely all we need.

He has a 2.5" lift so these are likely not enough.

 

[limeade]

Can't disagree with your logic. In my case, I have a short leveling lift and 5 degrees of caster. The Mopar LCAs should get me to 6 degrees. Do you think that 6 degrees isn't enough for on road driving?

My comfort range for on road driving is mid to upper 6's. That gives you the best on road "feel", minimizes wandering, and good return to center. But 6 degrees is a whole lot better than stock!

The Mopar LCA's are cheap enough that if you don't think it's enough caster, you should be able to easily sell them and not be out a lot of money. Problem is, then you'd have to put on another set of LCA's, and they get to be a PITA!!

 

[Rodeoflyer]

Don't buy mopars fixed length, factory bushing control arms.. waste of money if you ever plan a larger than 2.5 lift.. plus they have the same shitty bushing. Makes no sense to me.

Many have disputed my posts with bullet points including price and warranty issues so fwiw...

 

[RedundanT]

Adjustable control arms weak? Tell that to Spence at Core 4X4. LOL

 

[mschlott]

He has a 2.5" lift so these are likely not enough.

I just measured my caster with my not-highly-accurate mobile app. Have one of those Johnson protractors on order. As measured on the front of my differential housing 1.8 to 2 degrees. This puts me at about 4 to 4.2 degrees. I'll check again once I get the protractor and I'll measure with my Jeep backed in to the garage and average the measurements to allow for any slope on the floor.

Assuming the following, none of which I know for a fact...
The Mopar 2 inch lift LCAs are 1/4 inch longer than stock - I heard this somewhere
The distance between the upper control arm mount and the lower control arm mount is about 8 3/4 inches. I eyeballed this with a measuring tape.
I'm currently at 4 degrees caster. - Measured with cell phone with very little consistency.
I will end up at about 5.6 degrees caster.

This will likely be a good improvement, but not the 6 to 6.5 that most people recommend. Depending on what I measure with the protractor, I may give this a shot. I never intend to go with more lift and I don't mind re-doing it if it does not work out.

 

[rickinAZ]

I just measured my caster with my not-highly-accurate mobile app. Have one of those Johnson protractors on order. As measured on the front of my differential housing 1.8 to 2 degrees. This puts me at about 4 to 4.2 degrees. I'll check again once I get the protractor and I'll measure with my Jeep backed in to the garage and average the measurements to allow for any slope on the floor.

Assuming the following, none of which I know for a fact...
The Mopar 2 inch lift LCAs are 1/4 inch longer than stock - I heard this somewhere
The distance between the upper control arm mount and the lower control arm mount is about 8 3/4 inches. I eyeballed this with a measuring tape.
I'm currently at 4 degrees caster. - Measured with cell phone with very little consistency.
I will end up at about 5.6 degrees caster.

This will likely be a good improvement, but not the 6 to 6.5 that most people recommend. Depending on what I measure with the protractor, I may give this a shot. I never intend to go with more lift and I don't mind re-doing it if it does not work out.

I'm with you. Many have offered up sage advice about the flexibility for a larger lift. That is a good point for most, but I modify my Jeeps straight away after I get them. I've never gone back and (re)changed out parts. If one is in set-it-and-forget-it mode, paying 5x more for adjustability is not the best place to spend cash. My biggest consideration is whether the 24.25" fixed length arms will actually hit the sweet-spot for my application.

As usual, you folks are a wealth of information. I continue to be amazed at the breadth of knowledge and willingness to share. That said, where was all of the good advice when I bought two 3.8 liter JKs? They literally ran like a Pentastar with two plug wires disconnected.

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