Control Arm Lengths

Ericshere03

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I already know where this thread is going, but bear with me.

I was reading through the currie instructions for the 4" lift. Does anyone actually use Curries recommended control arm lengths for their TJ with 4" lift and SYE (Yes the SYE matters to you newbies)??? because I realized they're basically stock length.

"Currie control arms come preset for a TJ with a 4” lift, a transfer case slip yoke eliminator kit, and a CV driveshaft. Front upper arms - 15” c-c Rear upper arms - 13 1/2” c-c All lower arms - 15 3/4” c-c "

Compare that to stock, but let me chart it for your eyeballs;

STOCK | Currie
Front Lower 15.75" | 15.75"
Front Upper 15" | 15"
Rear Lower 15.75" | 15.75"
Rear Upper 13.25" | 13.5"

Had I realized this, I would have ALWAYS used stock arms and just modify the rear upper mount for that quarter inch... I understand the need for fine tuning, but jeeze, I feel dumb spending thousands for custom arms when all i needed was a quarter inch on one pair. I like the idea of stock replacement when you can go to any parts store for a replacement.

I was thinking of going all out this time around and just go Full Currie. I have done Synergy, JKS, OME, Rough Country (HEY! We've all done it) and of course my custom brewed setup on my jeeps of the past. But are we overlooking the opportunity for a cheap set of arms??? Like the ZJ setup, stock replacement parts but upgraded enough for our rigs. I also have an LJ, so my need for a steep pinion is greatly reduced, perhaps allowing ALL stock arms. I may have to go to the garage and put the jeep on some stands and "simulate" a 4" lift and see what the numbers look like.

For YEARS (since my first TJ in 2006) this has been me;
goldblum-quote.jpg
 
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Guess I don't feel too bad about having a 4" lift and having stock control arms cept for a cheap rear upper set.

I will say this...my arms bind up way before I hit my bump stops or things run into things. Which means I've chartered a course to rip off brackets.

It's all about the joints and the strength of better materials.

-Mac
 
Guess I don't feel too bad about having a 4" lift and having stock control arms cept for a cheap rear upper set.

I will say this...my arms bind up way before I hit my bump stops or things run into things. Which means I've chartered a course to rip off brackets.

It's all about the joints and the strength of better materials.

-Mac

Did you “reset” your bushings? You install a lift with your control arms loose. When you put the weight back on the vehicle, bounce the suspension and then go back and torque the bolts … the range of motion should be the same and dictated by the shock travel and/or bumpstops. I think OME is 11” of travel for their LT shocks, if those don’t bind and rip bushings then most other suspensions won’t either because it’s rare to go above 11” of wheels travel.
 
I already know where this thread is going, but bear with me.

I was reading through the currie instructions for the 4" lift. Does anyone actually use Curries recommended control arm lengths for their TJ with 4" lift and SYE (Yes the SYE matters to you newbies)??? because I realized they're basically stock length.

"Currie control arms come preset for a TJ with a 4” lift, a transfer case slip yoke eliminator kit, and a CV driveshaft. Front upper arms - 15” c-c Rear upper arms - 13 1/2” c-c All lower arms - 15 3/4” c-c "

Compare that to stock, but let me chart it for your eyeballs;

STOCK | Currie
Front Lower 15.75" | 15.75"
Front Upper 15" | 15"
Rear Lower 15.75" | 15.75"
Rear Upper 13.25" | 13.5"

Had I realized this, I would have ALWAYS used stock arms and just modify the rear upper mount for that quarter inch... I understand the need for fine tuning, but jeeze, I feel dumb spending thousands for custom arms when all i needed was a quarter inch on one pair. I like the idea of stock replacement when you can go to any parts store for a replacement.

I was thinking of going all out this time around and just go Full Currie. I have done Synergy, JKS, OME, Rough Country (HEY! We've all done it) and of course my custom brewed setup on my jeeps of the past. But are we overlooking the opportunity for a cheap set of arms??? Like the ZJ setup, stock replacement parts but upgraded enough for our rigs. I also have an LJ, so my need for a steep pinion is greatly reduced, perhaps allowing ALL stock arms. I may have to go to the garage and put the jeep on some stands and "simulate" a 4" lift and see what the numbers look like.

For YEARS (since my first TJ in 2006) this has been me;
View attachment 410874

No, and that's not the way to set up your arms. There's not "a" measurement you should follow. I don't care if Currie did publish that. It's wrong if that’s the end of the instructions.
 
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No, and that's not the way to set up your arms. There's not "a" measurement you should follow. I don't care if Currie did publish that. It's wrong.

Not necessarily. Those measurements are the base from which you start from. If you read on in the instructions you get to this:

1 For best results we recommend following this adjustment process - front and rear - to neutralize any load being placed on the suspension by possible
abnormalities of your vehicle. With the vehicle on the ground, disconnect the trac bar from the differential and disconnect one of the upper control arms
(on diff erential end only). Center the differential under the vehicle by adjusting the length of the bar. Tighten and torque the trac bar bolt. Re-install the
previously removed upper control arm. If the bolt no longer lines up with the bolt hole - do not force it - adjust the length of the arm until the bolt will
slide thru easily. Tighten and torque the bolt.
2 Set your angles. Front differential caster must be 5 degrees positive. Rear differential pinion angle must be 2-3 degrees down in relationship to the
driveshaft angle when using a conventional driveshaft and 1 degree down when using a double cardan (CV) style driveshaft. If your specs. do not match
these parameters - you must adjust the upper and lower control arms until they do.

I know for a fact that Blaine has recommended the same procedure (caster angle notwithstanding) here on more than one occasion. Whether folks choose to follow it or not is a different story.
 
Not necessarily. Those measurements are the base from which you start from. If you read on in the instructions you get to this:

1 For best results we recommend following this adjustment process - front and rear - to neutralize any load being placed on the suspension by possible
abnormalities of your vehicle. With the vehicle on the ground, disconnect the trac bar from the differential and disconnect one of the upper control arms
(on diff erential end only). Center the differential under the vehicle by adjusting the length of the bar. Tighten and torque the trac bar bolt. Re-install the
previously removed upper control arm. If the bolt no longer lines up with the bolt hole - do not force it - adjust the length of the arm until the bolt will
slide thru easily. Tighten and torque the bolt.
2 Set your angles. Front differential caster must be 5 degrees positive. Rear differential pinion angle must be 2-3 degrees down in relationship to the
driveshaft angle when using a conventional driveshaft and 1 degree down when using a double cardan (CV) style driveshaft. If your specs. do not match
these parameters - you must adjust the upper and lower control arms until they do.

I know for a fact that Blaine has recommended the same procedure (caster angle notwithstanding) here on more than one occasion. Whether folks choose to follow it or not is a different story.

Of course. In the context of the OP’s post he’s assuming wrongly that Currie set those numbers as the final length for a 4” lift. I personally know Currie did not publish that as a final length, but as a starting point. 👍🏼 sorry if that came across confusing, but the confusion is in the OP.
 
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