Author Topic: longer control arms  (Read 1391 times)

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Offline dexetr30

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longer control arms
« on: February 03, 2009, 03:59:44 PM »
This is hypothetical, something I've been thinking about. I've been thinking about cutting the lower control arm brackets off (front and rear) and moving them as close as possible toward the tc skid plate. If I keep the cuts clean I should be able to reuse the mounting brackets. I want to fab my own control arms. I was thinking of using some 1.5" O.D. x .120" DOM for the tubes along with some Johnny Joints on one end and some poly bushing joints on the other end.

Ballistic Fab. has most of the parts I would need.

Thoughts or ideas?
« Last Edit: February 03, 2009, 04:00:29 PM by dexetr30 »
02 2.5.L automatic: 4.0L t.b., 4.0l air intake, K&N filter, Scream'n Demon coil, 8.5mm MSD Super Conductor plug wires, Stage 1 Jet Chip, 29" BFG all terrain KO's. Taurus E-fan, Hummer front bumper, Skyjacker high capacity trans pan, 48" hi-lift, Rubi susp w. 3/4" BB.

Mr_Random

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Re: longer control arms
« Reply #1 on: February 03, 2009, 07:04:02 PM »
This is hypothetical, something I've been thinking about. I've been thinking about cutting the lower control arm brackets off (front and rear) and moving them as close as possible toward the tc skid plate. If I keep the cuts clean I should be able to reuse the mounting brackets. I want to fab my own control arms. I was thinking of using some 1.5" O.D. x .120" DOM for the tubes along with some Johnny Joints on one end and some poly bushing joints on the other end.

Ballistic Fab. has most of the parts I would need.

Thoughts or ideas?

It's a little bit harder to figure out than just moving them... If you're great at geometry and know how to best approximate the correct control arm angles from ride height to full droop to closely match stock, then sure you can go ahead and figure it out! Otherwise there are control arm calculators somewhere on the net... It shouldn't be too hard of a search.

Otherwise, your control arm design seems to match that of major brands, so you can't really go wrong there.

Offline Jeffy

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Re: longer control arms
« Reply #2 on: February 03, 2009, 07:31:17 PM »
Hmm, I has a post written but didn't upload it.  I agree, the geometry is important.  Otherwise, the suspension will bind.  Really though, unless you're wanting large tires like 35's, there really isn't a need to go with a "Long arm" setup.
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Mr_Random

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Re: longer control arms
« Reply #3 on: February 03, 2009, 09:12:10 PM »
Hmm, I has a post written but didn't upload it.  I agree, the geometry is important.  Otherwise, the suspension will bind.  Really though, unless you're wanting large tires like 35's, there really isn't a need to go with a "Long arm" setup.

Correct, and considering it's a TJ, they can fit larger tires with less lift (than my XJ), so CA angles are less drastic.

But still, if you're a nut for ride and flex quality, go ahead and long arm it! If you can do it yourself and do it right, there's no good reason not to...

Offline aw12345

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Re: longer control arms
« Reply #4 on: February 04, 2009, 05:39:23 AM »
Good short arms with no more than about a 4" lift work well. Use currie control arms 4 link or tri link the rear, use something like a ainti rock swaybar in the front and if you want to make it even sweater use one in the rear and that Jeep will tackle some serious rocks and other terain with ease, The biggest thing is to get the back to flex well and use some kind of sway bars to keep the body from rolling side to side, Try 8 hours of rough terain riding and you will figure out what I mean, the rear trackbar has a bad habit of jerking you side to side on the rough stuff not to speak of rear steer. I am very happy with how my little Jeep wheels these days, has not to many problems keeping up with the guys with long arms and 35-37" tires
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Offline dexetr30

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Re: longer control arms
« Reply #5 on: February 04, 2009, 07:54:16 AM »
I've got about 2.25" of lift right now. That's one of the things that makes this hypothetical. The way it is now I may just build stock length arms using the same parts I mentioned in my original post. Although I'm not sure I could build them any cheaper than I could buy them already made to the specs I want. Q-tec has a set here made by Crown but they look flimsy.

At the very least I'll be boxing in my stock upper and lower arms and replacing the bushings with some poly.

I'm cheap and broke. These 2 things make me want to build my own stuff when I can. As the saying goes: "I've done so much, with so little, for so long, that now I can do anything with nothing."
02 2.5.L automatic: 4.0L t.b., 4.0l air intake, K&N filter, Scream'n Demon coil, 8.5mm MSD Super Conductor plug wires, Stage 1 Jet Chip, 29" BFG all terrain KO's. Taurus E-fan, Hummer front bumper, Skyjacker high capacity trans pan, 48" hi-lift, Rubi susp w. 3/4" BB.

Offline Bounty Hunter

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Re: longer control arms
« Reply #6 on: February 04, 2009, 12:20:58 PM »
By changing the length of the LCA's you'll be affecting anti-squat and other handling characteristics, so unless you have a good understanding of all the principles involved......

Offline dexetr30

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Re: longer control arms
« Reply #7 on: February 04, 2009, 01:21:16 PM »
Stock lower control arm length is 15 3/4" (correct me if I'm wrong. I don't have my Jeep here to take a measurement right now.) if I remember correctly. Figuring things out... I'd need to raise the suspension at least 3" before things started to change. And at that point I'd only need to lengthen the control arms 1/4". I figure there's no point in building a d.i.y. long arm kit until I start getting into the 4" range, and even then it only needs to be 16 3/8" to stay close to the stock angles. 5/8" difference at 4" of lift isn't enough to make me want to build something like I'm describing at this point, especially since I haven't even broken the 3" mark yet. Still, it's fun to think about and play with the mathematics of it.

Interestingly enough, the upper arms don't really need to be elongated until you hit 5" of lift and even then they only need to be stretched 1/4". It's funny how small lengths make such a difference.
« Last Edit: February 04, 2009, 01:43:23 PM by dexetr30 »
02 2.5.L automatic: 4.0L t.b., 4.0l air intake, K&N filter, Scream'n Demon coil, 8.5mm MSD Super Conductor plug wires, Stage 1 Jet Chip, 29" BFG all terrain KO's. Taurus E-fan, Hummer front bumper, Skyjacker high capacity trans pan, 48" hi-lift, Rubi susp w. 3/4" BB.

Offline aw12345

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Re: longer control arms
« Reply #8 on: February 04, 2009, 03:38:15 PM »
at 4" of lift you want your arms slightly longer than 16" . You do not want to box the stock arms since they do flex. It's one of the things that makes the stock control arms work well, they tend to twist and give you a fair amount of flex. Most aftermarket control arms shred bushings and bind with hard wheeling, for it to live they need either heims or Johnny joints on both ends or atleast a rubber bushing one one end and johnny joint or heim on the other. Even on long arm suspensions Poly bushings tear up in short order. For anti squat in the rear some of the 4 links or tri links do a good job even on a short arm suspension
2006 Jeep Wrangler TJ SE
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Offline aw12345

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Re: longer control arms
« Reply #9 on: February 04, 2009, 05:05:39 PM »
Here is actually the first question that should have been asked, what do you intend to do with your Jeep?
Different terain kinda asks for somewhat different solutions. What we mostly do is crawl over rocks
2006 Jeep Wrangler TJ SE
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Offline Bounty Hunter

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Re: longer control arms
« Reply #10 on: February 04, 2009, 06:59:25 PM »
I had 5.5" coils on my MJ, added about 1" to the UCA's and about 1.5" or so to the LCA's.

Don't forget to factor in lengthening the control arms in order to regain the original or longer wheelbase.  I usually set the wheelbase first with the LCA's, then build the UCA's for the proper caster and pinion angles.

Offline dexetr30

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Re: longer control arms
« Reply #11 on: February 05, 2009, 08:56:12 AM »
Here is actually the first question that should have been asked, what do you intend to do with your Jeep?
Different terrain kinda asks for somewhat different solutions. What we mostly do is crawl over rocks

Right now it's my DD with some light trail rides now and then on the weekends. Sometime in the future (not sure how far out right now) I'd like it to be a well rounded trail rig (with some street ability) able to take on just about any trail this area (northeast PA) has to offer. We have plenty of rock, along with mud and just about anything else you could think of... with sand being the one think we do not have. However, we do have plenty of coal silt which does share the same characteristics as sand.
02 2.5.L automatic: 4.0L t.b., 4.0l air intake, K&N filter, Scream'n Demon coil, 8.5mm MSD Super Conductor plug wires, Stage 1 Jet Chip, 29" BFG all terrain KO's. Taurus E-fan, Hummer front bumper, Skyjacker high capacity trans pan, 48" hi-lift, Rubi susp w. 3/4" BB.

Offline aw12345

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Re: longer control arms
« Reply #12 on: February 05, 2009, 06:18:56 PM »
It's probably best to start wheeling and see what works for you. What you suggested actually works pretty well
Mid arms on the bottom and short arms up front, I would still make a trilink or four link for the rear simply because it rides so much better on the traik. One of my buddies has his Jeep set up this way and it wheels well, The only thing you need to do is replcae the rubber bushings on the front axle with currie Johnnu joints they make a kit for that. Otherwise you will eventually tear the right side upper control arm mount of the front axle. Also for heavy trail use on rocks and such don't bother with Urethane or poly bushings they will shred. Other than that get rid or move anything that hangs down underneath. Move the rear shocks out of harms way, belly it up and lock the little beasty and you will be amazed where it will go
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Offline dexetr30

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Re: longer control arms
« Reply #13 on: February 06, 2009, 07:52:00 AM »
It's probably best to start wheeling and see what works for you. What you suggested actually works pretty well
Mid arms on the bottom and short arms up front, I would still make a tri link or four link for the rear simply because it rides so much better on the trail. One of my buddies has his Jeep set up this way and it wheels well, The only thing you need to do is replace the rubber bushings on the front axle with Currie Johnny joints they make a kit for that. Otherwise you will eventually tear the right side upper control arm mount of the front axle. Also for heavy trail use on rocks and such don't bother with Urethane or poly bushings they will shred. Other than that get rid or move anything that hangs down underneath. Move the rear shocks out of harms way, belly it up and lock the little beasty and you will be amazed where it will go

Seems as though moving the rear shocks out of the way is the simplest thing I could do right now. Can't tell you how many times they have been banged up and beaten on. I've been looking at these. Although they don't do a real good job at actual relocation, I think they may give me some more flex by allowing the axle tubes to pivot/rotate a little more during articulation. I do like the relocation job Stu Olson did, particularly how he relocated the bottom mount. The bottom I could handle fab wise but the upper half is a bit above my fab capabilities right now. One good thing, I have welding and fabrication classes coming up this spring at the local community college. So I'll have free range of all the fab equipment and welding equipment I can handle.

As for the Johnny Joints... I've thought of using them on both ends of the arms. However, I have heard that they transmit a lot of vibes and whatnot into the tub and frame if used on both ends. If it's true then I have to wonder if this is something that will be a nuisance to me. I honestly don't think it will bother me and it would allow for more articulation. Not to mention, wouldn't the body mounts absorb a lot of the vibes?
« Last Edit: February 06, 2009, 07:57:10 AM by dexetr30 »
02 2.5.L automatic: 4.0L t.b., 4.0l air intake, K&N filter, Scream'n Demon coil, 8.5mm MSD Super Conductor plug wires, Stage 1 Jet Chip, 29" BFG all terrain KO's. Taurus E-fan, Hummer front bumper, Skyjacker high capacity trans pan, 48" hi-lift, Rubi susp w. 3/4" BB.

Offline aw12345

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Re: longer control arms
« Reply #14 on: February 06, 2009, 03:24:26 PM »
As for shock relocation, you can just move the bottom mount behind the the lower cotrolarm mount works well. Mine has been like that for the last 7 months or so.

http://picasaweb.google.com/aartw12345/JeepModifications#5240887449510369906n

One of my wheeling buddies did something simular works well also Nth degree makes a relocator kit. The terra flex shock extenders just make it even worse had those and they are well made but do not help clearance any. As for the Johnny joints trasnmitting vibers they use Urethane bussings with a ball end in it no worse than any other control arm with Urethane bushings. I have 6 currie control arms on mine with Johnny hoints on them works well and lasts a lot longer than all the swivel arms and what not
2006 Jeep Wrangler TJ SE
2004 Jeep Wrangler TJ SE