Panhard and drag link angles?

thezentree

thezentree

RBS
Joined
Jul 21, 2023
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I know in a perfect world that flat, long, and totally parallel is how the drag link and panhard bar should be, but that’s not always possible. Is there a rule of thumb for how much angular separation is too much?

I’m trying to make my 3-linked 1st gen Tacoma be less bad, and found a sweet spot for a Barnes panhard bar mount on the axle. Steering clears everywhere and pushing the panhard mount forward of the axle tube makes the panhard and drag link parallel looking from the side, and got me another inch of uptravel from oil pan and upper link mount clearance.

Unfortunately the panhard and drag link are 3-4 degrees different when looking from the front. I realize this is going to cause some level of bumpsteer, but is it enough that I should make a custom panhard bracket? Or is it a “in reality it’s not going to matter that much” situation?

(This is also in my build thread but figured it’d get more exposure here)


IMG_6371.jpeg
 
Can you make a new frame side trackbar mount that lowers the frame side just a bit to get it closer?

Can you buy / make a drop Pittman arm?

How much street driving are you intending for this? It's probably fine and able to be overcome, just knowing it will happen as is.
 
I made this little simulator so I could measure/visualize the deflection from mismatched angles/lengths when I was setting up my track bar and drag link: Track Bar and Drag Link Simulator

Even with an 8 inch difference in length between the two I was surprised to see there wasn't too much deflection if I was able to keep them close vertical-space-wise. Play around with it and see what your results might be. Let me know if there are any issues or changes needed.
 
Last edited:
Opiebennett said:
Can you make a new frame side trackbar mount that lowers the frame side just a bit to get it closer?

Can you buy / make a drop Pittman arm?

How much street driving are you intending for this? It's probably fine and able to be overcome, just knowing it will happen as is.
Click to expand...
Yeah a frame side bracket would probably be easier than the axle side bracket...

It's not going to be a daily driver but it'll see hours on the interstate going to different offroad parks, and I will probably drive it to work sometimes.

holdmypocket said:
I made this little simulator so I could measure/visualize the deflection from mismatched angles/lengths when I was setting up my track bar and drag link: Track Bar and Drag Link Simulator

Even with an 8 inch difference in length between the two I was surprised to see there wasn't too much deflection if I was able to keep them close vertical-space-wise. Play around with it and see what your results might be. Let me know if there are any issues or changes needed.
Click to expand...
Thanks, I'll play with this later this week when I have time to go get measurements.
 
IMG_6397.jpeg


I like this better. Like half a degree difference. I lost a little bit of uptravel from the panhard hitting the oil pan at full passenger side stuff but I suspect the tires will get into the fenders before that happens.
 
really if you have it all tacked up, just cycle it up and down and you'll see how crazy the bump steer is

maybe strap the knuckle to the axle so the knuckles don't move and then you'll see all the bump steer in the steering wheel
 
lol you and your facts and logic

I cut the tower off so I could finish weld it, but I'm going to try to get it back on and painted sometime this weekend and I'll give that a shot. I think it's about as good as I'm going to get it now though, so I'll probably just burn it in at this point.
 
holdmypocket tried to pm but it was blocked. That simulator is awesome, sure beats my colored pencil graph paper drawings. I’m computer dumb, will that work on a phone?
 
WiscoF100 said:
holdmypocket tried to pm but it was blocked. That simulator is awesome, sure beats my colored pencil graph paper drawings. I’m computer dumb, will that work on a phone?
Click to expand...
I think I fixed my PM settings, that was weird. Anyway, I'll throw the simulator up on my hosting and that way you can just go to the link and view it in your browser. I'm not sure how easy it will work on mobile as-is (because of the size of the points you click and drag) but I can work on that too.
 
WiscoF100 said:
holdmypocket tried to pm but it was blocked. That simulator is awesome, sure beats my colored pencil graph paper drawings. I’m computer dumb, will that work on a phone?
Click to expand...
Well, it doesn't work on mobile (touch/tap and drag doesn't work in mobile browsers currently) but as long as you have a computer you can simply go here and use it instead of downloading it from irate4x4.com resources:


These are some good inputs to start with in the screenshot. You will want to enter negative values for the angle degree inputs. And don't forget to consider the vertical separation of the linkages (how far apart are they), and where the mounting points are in relation to one another if you want an accurate path of travel to be drawn.

Screenshot 2024-09-26 at 11.22.50.png
 
Threw a pic in solidworks to try this idea of modeling the relation between the drag link and panhard. Despite the 12 degrees of angle, this doesn't seem that bad?

Screenshot 2024-09-26 150019.png
 
Yeah it looks pretty good to me. The amount of deflection increases as you droop/stuff but I imagine stuff is a third of droop and you’re not drooping much on the highway.
 
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