Adjustable Control Arm Options

So it seems to me that if you just want to get one set for the front and one for the rear, it's recommended to get front lowers and rear uppers. Can anyone speak to the reasoning behind that, rather than... say... front uppers and rear lowers? I've just been giving some consideration to the evolution of my build and would love to hear the rationale. Thanks in advance!
 

rinkishjk

New member
People go with front lowers to adjust for more caster. If u used front uppers and stock lower arms, u would not be able to make the arms short enough to add caster. For the rear the upper arms are used to adjust the pinion angle. Same problem with length is why u do uppers in the rear as opposed to lowers.
 

wayoflife

Administrator
Staff member
So it seems to me that if you just want to get one set for the front and one for the rear, it's recommended to get front lowers and rear uppers. Can anyone speak to the reasoning behind that, rather than... say... front uppers and rear lowers? I've just been giving some consideration to the evolution of my build and would love to hear the rationale. Thanks in advance!

As mentioned, adjustable front lowers will allow you to adjust your caster and this is helpful to address flighty handling after installing a lift. Rear uppers are ONLY needed IF you install an aftermarket u-joint style double cardan drive shaft. When you do that, it is REQUIRED to set your pinion angle in line with your drive shaft and the only way you can do that is with adjustable rear upper control arms.
 

07JKSahara

New member
As mentioned, adjustable front lowers will allow you to adjust your caster and this is helpful to address flighty handling after installing a lift. Rear uppers are ONLY needed IF you install an aftermarket u-joint style double cardan drive shaft. When you do that, it is REQUIRED to set your pinion angle in line with your drive shaft and the only way you can do that is with adjustable rear upper control arms.

Thread Hijack. I did rear uppers in my 2dr this weekend. Set them to Claytons recommended length. My pinion is still off by 2 or 3*. Should I add more? Still stock driveshaft, so I've heard both sides. What is the tolerance of the stock read in relation to degrees off? Thanks!
 
Thread Hijack. I did rear uppers in my 2dr this weekend. Set them to Claytons recommended length. My pinion is still off by 2 or 3*. Should I add more? Still stock driveshaft, so I've heard both sides. What is the tolerance of the stock read in relation to degrees off? Thanks!

Recommended lengths are just a starting point. Pinion 1-2* below the DS is fine. You might want to lengthen them a turn each.
 

wayoflife

Administrator
Staff member
Honestly, I don't know how you could even have a recommended control arm length setting as the length NEEDS to be determined by the angle of your pinion in relationship to the drive shaft.
 

jeeeep

Hooked
The length they have is stated in the instructions is stated as a starting length and you'll need to adjust to achieve the proper angle.

I think that's true for most instructions I've read in the various lifts I've helped install.
 

Panda

New member
Ok another hijack.. I'm planning on installing an after market rear drive shaft soon on my 2 door I just wanted to be clear on how this works, am I supposed to set the pinion parallel with the drive shaft so it angles up toward the transfer case? Also does anyone know will I hurt anything running the stock driveshaft with 4 inches of lift for awhile?
 
Ok another hijack.. I'm planning on installing an after market rear drive shaft soon on my 2 door I just wanted to be clear on how this works, am I supposed to set the pinion parallel with the drive shaft so it angles up toward the transfer case? Also does anyone know will I hurt anything running the stock driveshaft with 4 inches of lift for awhile?

Only thing your gonna hurt is your drive shaft. Lol.
 

cozdude

Guy with a Red 2-Door
Ok another hijack.. I'm planning on installing an after market rear drive shaft soon on my 2 door I just wanted to be clear on how this works, am I supposed to set the pinion parallel with the drive shaft so it angles up toward the transfer case? Also does anyone know will I hurt anything running the stock driveshaft with 4 inches of lift for awhile?

Yes it should point right at the transfer case.

Do you already have the rear uppers installed panda? If so just set you pinion angle now with the stock one to help reduce the wear on it till you replace it.
 

Panda

New member
Yes it should point right at the transfer case.

Do you already have the rear uppers installed panda? If so just set you pinion angle now with the stock one to help reduce the wear on it till you replace it.

No I don't have the rear uppers yet, soon I hope, thanks Coz! :thumb:
 

07JKSahara

New member
Honestly, I don't know how you could even have a recommended control arm length setting as the length NEEDS to be determined by the angle of your pinion in relationship to the drive shaft.

I understand this, I know it was a ballpark starting point, my real question is do I have a couple degrees of "tolerance" or should my pinion be addressed immediately?
 
Like said .. People will say the rear pinion should be inline, others say -1 to -2 below driveshaft with a double carden. Whatever works for you.
The stock shaft won't vibrate. Any correction is better then nothing IMO.
 

07JKSahara

New member
Like said .. People will say the rear pinion should be inline, others say -1 to -2 below driveshaft with a double carden. Whatever works for you.
The stock shaft won't vibrate. Any correction is better then nothing IMO.

Thanks. I appreciate the help/knowledge from everyone.
 

wayoflife

Administrator
Staff member
I understand this, I know it was a ballpark starting point, my real question is do I have a couple degrees of "tolerance" or should my pinion be addressed immediately?

Like said .. People will say the rear pinion should be inline, others say -1 to -2 below driveshaft with a double carden. Whatever works for you.
The stock shaft won't vibrate. Any correction is better then nothing IMO.

I disagree with it being a matter of "whatever works for you". Fact of the matter is, IF you do not have your pinion set correctly, your drive shaft WILL vibrate. IF you have enough slop in your control arms to allow for enough rotation of your axle when driving, a difference in angle MAY be something you want as when you drive, your pinion will sit more in line with your drive shaft.

You DO NOT need to set your pinion angle with a stock drive shaft as it has rzeppa joints and as mentioned, will not vibrate. A correction NEEDS to be made with an aftermarket drive u-joint style double cardan drive shaft. It is NOT a matter of "better than nothing".
 

07JKSahara

New member
I disagree with it being a matter of "whatever works for you". Fact of the matter is, IF you do not have your pinion set correctly, your drive shaft WILL vibrate. IF you have enough slop in your control arms to allow for enough rotation of your axle when driving, a difference in angle MAY be something you want as when you drive, your pinion will sit more in line with your drive shaft.

You DO NOT need to set your pinion angle with a stock drive shaft as it has rzeppa joints and as mentioned, will not vibrate. A correction NEEDS to be made with an aftermarket drive u-joint style double cardan drive shaft. It is NOT a matter of "better than nothing".

Cool, thanks. Based on this I think I'm good. Appreciate your help.
 
"Better than nothing" running the stock shaft.
I disagree with not setting pinion angle with the stock shaft. Why wouldn't one want to make it last as long as possible ?
 
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