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Panhard Bar Configuration

2K views 8 replies 7 participants last post by  johnsongrass1 
#1 ·
;) Can a panhard bar be mounted beneath a diff if there is sufficient clearance?:confused: The configuration is.... from the pivot point on the frame, the bar goes straight for 3" (parallel to the ground), then drops for 9" at a 60* angle and then straight for 12" (parallel to the top 3"). Would this be too much of a strain on the bends? What if the bar just dropped from the pivot point on the frame 9" and then went parallel to the ground and hooked up to the diff? Total length of the bar would be about 24". I know you can make it look like a pretzel, but wouldn't certain forces tend to make a difference when it comes to bends. Haven't seen anyone do it and wonder if it is feasible. Thinking outside of the box.:smash:
 
#2 ·
To get the best benefit from a panhard bar the bar needs to be set at the center of the rearend at ride height. To get the least side to side movement the bar should be as long as possible.

Any bends will be a weak point in the bar which can cause flex and eventual breakage.
Mark
 
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#3 ·
The roll center of the rear suspension is determined by the height of the panhard bar. The lower the roll center, the less lateral load is transferred relative to the entire load transferred by lateral acceleration. That said, it is not unusual to mount the panhard bar, or other axle lateral locating device, lower than the rear axle. In my opinion, lower than the axle centerline is preferred in many cases. Bends can be an issue as you suspect. Making the bar very substantial, both in diameter and wall thickness, can resolve that situation. As long as the bends are as gentle as can be arranged and the material is of sufficient stiffness, you can get away with some bends. Obviously the less, the better.
 
#7 ·
Weld a dropped anchor point bracket on the frame for the frame end of the bar, at the height that you intend to attach the bar to the axle.

As KMA4444 posted, it controls the roll center....NASCAR cars have the bar mounted low behind the axle, and the frame end is on the jackscrew mount so they can adjust it during a race.

1" diameter x .156" wall DOM(Drawn Over Mandrel) mild steel tube is what I use, it can be direct threaded for 3/4"-16 fine thread to accept a 3/4" rod end. Plenty strong enough for a few bends to be in it, it would take an accident impact to bend it.

Stock panhard on the '82-up Camaro/Firebird is just a 1/16" or so stamped piece of U-Channel and it has no problem being strong enough....there just isn't that huge a force on this bar unless you are autocrossing the car.
 
#8 ·
;) I've included some pictures of the panhard bar as best as I can. Been wrestling with this all summer (crusin') and you know it's there by the constant banging against the floor. The first picture shows it hooked up at the top by the brake line and link bars, the other photos show what I have to contend with (mufflers, pipes, etc..) The bar is at least 1/4"-1/2" from the floor. Very hard to depict the situation as there is no room for the camera. I think it would be very hard to have a dropped anchor point as there is a lot of stuff in the way.
 

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#9 ·
"The roll center of the rear suspension is determined by the height of the panhard bar."

It's just a theory but in real life, theories are just educated guesses and still under consideration by the engineers I know. Much of the PH theory doesn't take into consideration the spring table. If you omit the science of the spring table, then the RC needs to be placed in such a way that the front RC's are working together. That may or may not be higher or lower than the axle center line. Axle rotation as viewed from the side will also need considered.

On street driven cars where rear suspension vertical movement is pretty small generally speaking, the location, bends, angle between the mounting points matter but aren't critical in my opinion.

The PH don't have to be round either. They can be flat, T cross section, I beam, square, U shaped or many other shapes or combination of shapes. The mounting points dictate the suspension geometries and not the bends or shape.
 
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