When to order panhard/upper/lower rear control arms

[pholley526]

Hey everyone,
I am curious at what size lift you need to do one or the other, or all three. Do you have to order both upper and lower rear control arms to get pinion angle correct??

 

[NJGX]

Rear uppers dictate pinion angle, lowers locate the axle forward/back in the center of the wheel well, and panhard centers the axle left/right.

I am at 3" lift and long(er) travel in the rear and would still set all the components at, or very close to stock length. My current travel limitation is due to my straight OEM lowers contacting the axle housing at full droop, so something like Dobinsons rear lower arm that has a bend would allow more travel. I think their upper arms have an offset mount as well to give some more clearance on the gas tank.

Even with my lift, my axle is off center to the passenger side by 1/4" at most (not a super accurate measurement to make). I'd only replace it if I wanted to beef it up. Keep in mind that extending the panhard bar may push the driveshaft too close to the gas tank skid when the suspension is compressed.

 

[HomersCanyonero]

Rear uppers dictate pinion angle, lowers locate the axle forward/back in the center of the wheel well, and panhard centers the axle left/right.

I am at 3" lift and long(er) travel in the rear and would still set all the components at, or very close to stock length. My current travel limitation is due to my straight OEM lowers contacting the axle housing at full droop, so something like Dobinsons rear lower arm that has a bend would allow more travel. I think their upper arms have an offset mount as well to give some more clearance on the gas tank.

Even with my lift, my axle is off center to the passenger side by 1/4" at most (not a super accurate measurement to make). I'd only replace it if I wanted to beef it up. Keep in mind that extending the panhard bar may push the driveshaft too close to the gas tank skid when the suspension is compressed.

Nice explanation. I'm not a super expert on these rear parts, but I had considered upgrading the rear lower control arms with beefier ones that had an offset. In the end, I decided not to touch the rear LCAs nor the rear UCAs because I'm at most 2.5" taller in the rear when fully empty and more like 1.75" taller with my solo weekend camping gear. Nothing was hitting anything, so I didn't see a need to change these rear components.

All I did was change the rear sway bar end links with ones that were 1" taller (Proforged ones for 4Runner) to level out the rear swaybar somewhat back to stock.

 

[captainva]

You want an EIM Keith panhard correction kit to regain your factory geometry at a higher ride height. The panhard bar must be level at ride height for correct geometry. If you get an adjustable panhard bar and correct your axle to be centered at ride height, you actually increase the movement of the axle side to side. Additionally without it being level, the rear roll center is below the ground. This leads to the back end moving around and not following the front as well which requires more steering inputs on the highway and makes the vehicle feel less stable.

 

[captainva]

Rear uppers dictate pinion angle, lowers locate the axle forward/back in the center of the wheel well, and panhard centers the axle left/right.

I am at 3" lift and long(er) travel in the rear and would still set all the components at, or very close to stock length. My current travel limitation is due to my straight OEM lowers contacting the axle housing at full droop, so something like Dobinsons rear lower arm that has a bend would allow more travel. I think their upper arms have an offset mount as well to give some more clearance on the gas tank.

Even with my lift, my axle is off center to the passenger side by 1/4" at most (not a super accurate measurement to make). I'd only replace it if I wanted to beef it up. Keep in mind that extending the panhard bar may push the driveshaft too close to the gas tank skid when the suspension is compressed.

This is all correct and to add to this, going long travel it is a certainty that your driveshaft will hit your gas tank skid on the drivers side (especially if you upgrade to thicker skids). Realigning the axle back to center with a panhard correction will only make this worse as you are pushing it towards to drivers side. The solution is to cut your skid either way but something to keep in mind. If you are doing a simple lift like Bilsten 5100s, upper and lower arms are not necessary. Anything long travel and you need lower arms for sure but a panhard correction is never a bad idea either way.

 

[ArBrnSnpr]

I have adjustable uppers, lowers, pan hard bar, EIMKeith pan hard bar relocation bracket and EIMKeith lower control arm body mount skids.

I have metaltech heavy long travel springs and Radflo 2.5 long travel shocks and as mentioned, I have gouged my factory gas tank skid with my drive shaft a few times. I beat it back into place because I didn't want to take away that area of protection on the gas tank if it is prone to contact.

I have my upper and lower arms extended 1" to center my wheel fore/aft in the wheel wheel.

The arms travel in a radius and at 3" of lift, the wheel sits closer to the rear door than it does at factory ride height.

I have a high-clearance rear bumper so I was able to push my axle back a bit more than stock, gaining me a bit more wheel base and suspension travel (my brackets don't cause the arms to bind like the factory mounts do).

The EIMKeith PHC bracket is amazing, but it won't address the left/right position of the axle with a factory length pan hard bar. An adjustable bar and the bracket gives true geometry correction and a very smooth ride while tracking straight over bumps at speed.

 

[NJGX]

Just for reference, here's a picture of my current setup of Dobinsons IMS long travel shocks, Dobinsons 701v variable rate LT springs, 2" bump stop spacer, 2nd gen 4Runner sway bar end links, extended brake lines, and factory upper/lower/panhard bar.

The bottom before pic is Bilstein 5160s, Dobinsons 677v variable rate LT springs, 2nd gen 4Runner sway bar end links, and stock everything else.

Driveshaft doesn't contact the factory gas tank skid. Sway bar links still allow for a little more travel as they are not in line with the sway bar at full droop. Brake lines have plenty of slack. Bump stop extensions fit perfectly for keeping the shock from bottoming out and allowing the 34s to get tucked up tight. Offset/adjustable upper and lower links would grant slightly more down travel, but idk how much more I'd realistically need. At this point, I'd rather save the $600 for other mods. However, if I end up bending or breaking a stock control arm, I'll absolutely use that opportunity to upgrade.

 

[captainva]

Just for reference, here's a picture of my current setup of Dobinsons IMS long travel shocks, Dobinsons 701v variable rate LT springs, 2" bump stop spacer, 2nd gen 4Runner sway bar end links, extended brake lines, and factory upper/lower/panhard bar.

The bottom before pic is Bilstein 5160s, Dobinsons 677v variable rate LT springs, 2nd gen 4Runner sway bar end links, and stock everything else.

Driveshaft doesn't contact the factory gas tank skid. Sway bar links still allow for a little more travel as they are not in line with the sway bar at full droop. Brake lines have plenty of slack. Bump stop extensions fit perfectly for keeping the shock from bottoming out and allowing the 34s to get tucked up tight. Offset/adjustable upper and lower links would grant slightly more down travel, but idk how much more I'd realistically need. At this point, I'd rather save the $600 for other mods. However, if I end up bending or breaking a stock control arm, I'll absolutely use that opportunity to upgrade.

View attachment 2890669

Still keeping the rear sway bar on the truck is the key to not having driveshaft skid contact. I removed my rear sway bar and now mine contacts

 

[captainva]

I have adjustable uppers, lowers, pan hard bar, EIMKeith pan hard bar relocation bracket and EIMKeith lower control arm body mount skids.

I have metaltech heavy long travel springs and Radflo 2.5 long travel shocks and as mentioned, I have gouged my factory gas tank skid with my drive shaft a few times. I beat it back into place because I didn't want to take away that area of protection on the gas tank if it is prone to contact.

I have my upper and lower arms extended 1" to center my wheel fore/aft in the wheel wheel.

The arms travel in a radius and at 3" of lift, the wheel sits closer to the rear door than it does at factory ride height.

I have a high-clearance rear bumper so I was able to push my axle back a bit more than stock, gaining me a bit more wheel base and suspension travel (my brackets don't cause the arms to bind like the factory mounts do).

The EIMKeith PHC bracket is amazing, but it won't address the left/right position of the axle with a factory length pan hard bar. An adjustable bar and the bracket gives true geometry correction and a very smooth ride while tracking straight over bumps at speed.

Interesting that you say the EIM keith kit doesn't recenter the axle as it will pull the axle back to the drivers side when installed. It should do all of the correction without the need for an adjustable panhard bar

 

[ArBrnSnpr]

It doesn't shift the axle left or right, it raises the pan hard bar to be parallel to the axle per factory suspension geometry.

 

[Rednexus]

Since the hole on the axle side of the PCK bracket is on the same vertical plane as the OEM hole, and since the frame bracket for the bar does not change, shouldn't the axle be centered with the Eimkeith PCK, unless it was not centered prior to PCK installation? I have the PCK on my GX and have a perfectly level panhard bar, but haven't exactly checked if the axle is perfectly centered. It seems that if the axle was off center, that there may be something wrong elsewhere (i.e., bent frame, bent rear upper or lower control arms) to make it end up that way.

 

[ArBrnSnpr]

My frame is straight, my bar is brand new (I made it) and I installed my PCK bracket using a laser level and it fit perfectly between the existing bracket and the new bracket. I wasn't checking the hole alignment when I burned it in, but I know when I was running a factory bar and the EIMKeith bracket, my axle was still not completely centered. That was what prompted me to build an adjustable bar.

Looking at the pictures on the website (I'm not near my GX at the moment), the holes in the bar are in a straight vertical line. By increasing the distance between the axle and the frame and keeping the frame side anchor point in the same plain, that will pull the axle out of center. If the mounting hole options arched closer to the frame side mount as they got higher, that would align the axle differently.

It's been a bit since I've read the TR4 forum thread about the bracket, but I'm 99.99% certain that it says in there the bracket is designed to correct the bar's geometry and center of roll, which it does tremendously well. That doesn't center the axle though like an adjustable bar will.

You can use a piece of string a pencil and a piece of paper to see how.

I'm not an engineer, but I know my frame is straight, I know how to measure how much wheel is protruding from a wheel well, and I know an adjustable bar that was set longer than stock centered my axle.

 

[Rednexus]

Thanks for the explanation. I may take a look at mine, measure it, and see if it is centered or not.

Any pics of the DIY adjustable bar? A full custom bar or a modification to a factory bar? A new Moog bar is like $45 so it would seem to be an easy welding project to add in some adjustability into one.

 

[captainva]

It doesn't shift the axle left or right, it raises the pan hard bar to be parallel to the axle per factory suspension geometry.

But by making the panhard bar parallel and if the mount on the axle is still vertically in line with where it was, because geometry you have effectively lengthened the bar so the axle would shift to the drivers side

Since the hole on the axle side of the PCK bracket is on the same vertical plane as the OEM hole, and since the frame bracket for the bar does not change, shouldn't the axle be centered with the Eimkeith PCK, unless it was not centered prior to PCK installation? I have the PCK on my GX and have a perfectly level panhard bar, but haven't exactly checked if the axle is perfectly centered. It seems that if the axle was off center, that there may be something wrong elsewhere (i.e., bent frame, bent rear upper or lower control arms) to make it end up that way.

Exactly

 

[HomersCanyonero]

You want an EIM Keith panhard correction kit to regain your factory geometry at a higher ride height. The panhard bar must be level at ride height for correct geometry. If you get an adjustable panhard bar and correct your axle to be centered at ride height, you actually increase the movement of the axle side to side. Additionally without it being level, the rear roll center is below the ground. This leads to the back end moving around and not following the front as well which requires more steering inputs on the highway and makes the vehicle feel less stable.

I loved that video. Watched it like 10 times. Learned a new word "Sagitta" and there's even Sagitta calculators.

What I took from the video, is that there is no hope to fix this issue 100%. Best you can do is level the panhard connection brakets to be level, but nothing else can really fix this geometry issue back to stock because our rear lifts are changing the half-travel point and the full-droop and full-bump distances. And the panhard bar makes the wheels move up and down in a circular manner (which pulls/pushes the wheels off center when you flex).

Moreover, the more flex you have, the more the panhard bar either pushes or pulls the wheels away from center. So, you have to find the new half-center point and limit the the flex. In fact, there a part in the video where they say a really short panhard bar with new connection points works better at controlling the sagitta. It's counter-intuitive and mind-blowing.

Anyways, that's what I took from watching the video like 10 times.

 

[VSPro9]

This was super informative and now i have to spend more money on my rig for something i didn’t know was wrong

 

[Tanaman]

This was super informative and now i have to spend more money on my rig for something i didn’t know was wrong

This place will do that to a person! Happens to me all the time

This has been a good follow. Just here for the knowledge

 

[HomersCanyonero]

This was super informative and now i have to spend more money on my rig for something i didn’t know was wrong

What symptoms do you have related to the panhard bar being angled after a lift? Do you actually feel anything?

 

[VSPro9]

What symptoms do you have related to the panhard bar being angled after a lift? Do you actually feel anything?

i havent really noticed anything major, but to be honest when i got my GX it was so beat down i have no idea how a stock, well maintained GX rides.

 

[HomersCanyonero]

i havent really noticed anything major, but to be honest when i got my GX it was so beat down i have no idea how a stock, well maintained GX rides.

I think Ive felt the rear pull on me a handful of times in 5 years of ownership.

Up to this point I didn’t really know what it was, but I’ll pay more attention going forward.

My panhard bar is currently not level with the axle. Yet, I don’t feel the need to fix it because I really don’t feel any rear tracking issues in my daily driving.

It’s not too often that I go over speed bumps, pot holes, or make turns at fast speeds. You have to be flexing your suspension at speed in order to get that sagitta movement.