Adjustable rear control arms and pinion/driveshaft angle (1 Viewer)

[drowzyGX]

Hey Y’all,

Tried installing a set of Dobinson’s adjustable rear lower and upper control arms today, and realized I’m a little out of my depth. Got a few questions about the adjustable arms before I proceed.

My understanding of the purpose of adjustable rear arms is to help correct the pinion and driveshaft angle after a lift. However, the handful of videos I’ve found on how to install these on a GX have you measure the adjustable arms to match the OEM ones.

Now, I’m a total novice, but this seems…like a waste. Why buy and install adjustable arms if you aren’t adjusting them?

I don’t have any noticeable vibration while driving, and have pretty minimal lift (icon stage 2, stock weight springs). My OEM rear control arms definitely need to be replaced. The rubber is dried and cracked to hell.

1) can I just match oem length and install the Dobinson’s I bought, or should I go through the process of measuring my pinion angle and figure out what adjustments I need to make to control arms?
2) any guides you’d recommend for mathing out the adjustments? I’d like to avoid a process of adjusting 1/4” at a time, putting the arms back on, lowering the truck, measure angles, etc. figure there’s got to be a smarter way than simply guess and check.

 

[HomersCanyonero]

The rear lower control arms also have an offset. I think the offset helps articulate better and also clears hitting something under there.

And the tubing is way beefier than oem. So, it’s not just the adjustability that provides benefits of an aftermarket rear lower control arm.

In fact, I’m considering getting beefy heavy duty, offset, fixed length rear lower control arms from Apache Offroad.

 

[Adventurelife]

You're right the main benefit is to adjust the pinion angle, adjusting the upper is a pain in the ass, the lower is pretty easy you don't actually have to lift it to adjust them.

The starting point for almost everyone is the stock length, and most don't need much adjustment... so why bother, well most of them are more stout, the stock lowers are very easy to bend. Also the bushings are usually much better quality, better movement and longer life, so they will more more freely for longer. Also most are rebuildable so you can just carry some spare bushings with you. Finally, you need them to look cool.

 

[drowzyGX]

appreciate the input!

I’m gonna go ahead and install them at stock length, and, if I feel driveline vibrations (haven’t in the 3 years I’ve had a lift), then I’ll take the steps to measure pinion angle and adjust the arms.

 

[gcalaway]

how are you liking the dobinsons rear arms? I will be purchasing some replacements this week and those are a consideration but I have not found much information on them

 

[captainva]

I've had mine for almost 4 years now and they've held up great