Thread: 4 link or ladder?

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Jack, let me see if I can unshroud this Panhard bar thing for you. It is unclear whether René Panhard or Émile Levassor or one of their hired engineers came up with the Panhard bar, but I'm pretty sure that whomever came up with it, they installed the bar with the longest possible length to fit into the car and also installed it parallel with the road surface to prevent pre-loading one side of the car or the other from the neutral ride height position.
http://www.citroenet.org.uk/panhard-...anhard-01.html

Now, along comes some of us goofy hot-rodders and the Panhard bar looks like a good, cheap, easy way to prevent lateral body movement in relation to the differential housing and it is. Problem arises when the builder fails to take into consideration that the bar must be as long as possible to keep the degree of angularity as low as possible and prevent jerking the body laterally on bump and rebound.

Proper bar construction and installation would dictate that mounts would be constructed to attach to the frame and to the housing that would allow the attachment ends of the bar to be right at the brake backing plates on each side of the car, thus allowing the longest possible bar length within the space available. The bar doesn't necessarily have to be straight, it can be curved or bent up like a pretzel, so long as the attachment points are as far as possible apart from each other and each attachment points are parallel with the road surface and the material used is stiff enough to resist deflection. That's where the Panhard bar gets its bad name, when shadetree engineers make the bar short because it is easy and expedient to do so. In my experience on this rock, I have figured out that if anything can be FUBAR'd, human beings can and will do it.

Bottom line: A properly engineered and installed Panhard bar will do a fine job of locating the differential laterally to the body. Not as precisely as a Watt's Link, but good enough. The key is the length of the bar and having both attachment points parallel with the track surface at ride height.

Here's a hastily-drawn diagram carried out to the point of silliness to illustrate my meaning......

Here's another illustration of one of the abortions we most normally see, engineered and installed by Billy Joe Bob....

Billy Joe Bob is a great guy, Just needs to suspend his suspension engineering.

Technoman,
You don't mind if I give you a new nick name do you. I just hate to type anymore than I have to. The fact that I even typed that last sentence shows you how smart i am. Anyway, that drawing of the pretzel panhard bar makes me wonder how much lateral support it can give. It looks like I need to find a way to make a straight (or as straight as I can) panhard bar as long as I can, horizontal to the road surface, and still avoid the exhaust. This is going to take some doing. I will see what I can do.

Jack.

Originally Posted by Jack F

Technoman,
You don't mind if I give you a new nick name do you. Anyway, that drawing of the pretzel panhard bar makes me wonder how much lateral support it can give.

1. Technoman is fine with me. It's just that my mind works in mysterious ways and I enjoy conveying my opinion on technical things to other people. I will always endeavor to use sound engineering and math principles in my replies.

2. You're apparently an intelligent person and so I'm sure you realize that I was just trying to make a point about the fact that the bar could be bent up any way you want it as long as the attachment points are the same distance from the track surface (level) and the bar is as long as possible within the confines of the available space. As I said, the material used for such a pretzel bar would have to be stiff enough to prevent deflection.

Technoman,
Yes, I know it was just a illustration. Some times my humor (?) hides the obvious .

Jack.

Originally Posted by Jack F

Technoman,
Yes, I know it was just a illustration. Some times my humor (?) hides the obvious .

Jack.

It's all good.