3 link with panhard questions (continued)

[YotaAtieToo]

I read through this thread

https://www.pirate4x4.com/threads/3-link-panhard-question.876671/page-3

Maybe I missed it, but I couldn't find the answer to my question.

How would I determine ideal panhard height? I know that it needs to be parallel and as close to equal length as possible to the drag link. As it is, that should be easy.

The rig in question has little limitations on where I can put the panhard. As of now the frame has been cut off at the firewall and I'm building a new one where ever it needs to be, the axle is pushed in front of the engine, so I can basically put the panhard as high as I want. Rear is spua leaf springs for reference.

Right now I have it loosely mocked up with a store bought axle panhard mount, this puts the panhard basically right behind the drag link or slightly lower. It would be very easy to raise it 4-6" if that will be beneficial. It's been a while since really read into 3 link. I feel like the panhard height has a lot to do with body roll.

 

['84 Bronco II]

Watch the video in the roll center thread. Basically, higher = more resistance to body roll, but at the expense of high speed ride and handling.

 

[YotaAtieToo]

Watch the video in the roll center thread. Basically, higher = more resistance to body roll, but at the expense of high speed ride and handling.

OK, that's what I thought I remembered also. I'll probably just leave it as I have it mocked up that way I don't have to make the pass side frame rail even more wonky

 

[Treefrog]

The roll center of a panhard bar is can be approximated by the point at which it crosses through the center plane of the car, the farther from the the center line of the axle (front to back) the less accurate this is. To expand on what Bronco said, the closer it is in height to the cg the less roll, not necessarily the overall height of said point.

Another point to keep in mind is that if the roll center point is higher in the front, it will have roll understeer. Lower front, roll oversteer.

 

[YotaAtieToo]

The roll center of a panhard bar is can be approximated by the point at which it crosses through the center plane of the car, the farther from the the center line of the axle (front to back) the less accurate this is. To expand on what Bronco said, the closer it is in height to the cg the less roll, not necessarily the overall height of said point.

Another point to keep in mind is that if the roll center point is higher in the front, it will have roll understeer. Lower front, roll oversteer.

OK, so being that panhard front suspensions usually have a lower roll center due to frame restrictions. Would I be smart to raise the panhard 4-6" to increase stability?

Right now it's roughly even with the high steer arm, I can very easily raise it 4" at the axle, and go to the top of the frame. I'm not trying to build a moon buggy, but if I can build a little stability into it now why not.

 

[Treefrog]

OK, so being that panhard front suspensions usually have a lower roll center due to frame restrictions. Would I be smart to raise the panhard 4-6" to increase stability?

Right now it's roughly even with the high steer arm, I can very easily raise it 4" at the axle, and go to the top of the frame. I'm not trying to build a moon buggy, but if I can build a little stability into it now why not.

Correct me if i am wrong, it seems you are trying to lower body roll?

My understanding is that roll understeer is preferred by auto companies for reasons related to how drivers react when the car slides.

As for how much moving it up would change things also depends on the rear. A leaf sprung axle has a roll center defined as where a line from the spring eyes crosses a vertical line through the axle center line. For spring under, this puts it pretty low. The closer in height the roll centers are the flatter the roll axis. My understanding is that a flatter slope is preferred. Based on that, probably best to have the panhard mount lower.

 

[pennsylvaniaboy]

My understanding is the fatter and higher in the car you can get it the better it is for rollcenter etc

 

[thomas808]

im in the same boat playing with my front 3 link, 1998 tacoma. Im running a 2uz, so i have some oil pan issues i need to deal with... but im running my panhard almost perfectly horizontal as is my drag link.

Not much room to raise it higher at the moment, Ive also been runnin it with 100% AD and my front RC is lower than my rear (leafs) and my truck definitely feels like it wants to roll on most off camber drop ins.

Wanting to lower my AD to 70% and raise my panhard a wee bit if possible.

 

[Ghetto Fab.]

I like having the panhard more or less directly behind the draglink if possible.

I don't like having a lot of vertical distance between the two. Having that distance can induce bumpsteer when articulating.