Panhards

[choppedtop]

Didn't want to clutter up Freds build with this.
Here is a simple drawing of what different shaped panhard bars do to movement of rearend. As you can see, the straight bar only move the rearend to left when moved up or down about 3 1/2 inchs. With a angled bar, the rearend will move left and right, same with bar with 90 degree angle.
Comments, yes or no?

 

[old round fart]

I don't see how it makes a difference it the bar is straight or bent. It seems the two points is the only factor. How did you get those examples?

 

[choppedtop]

Hey John. I didn't think it did either. I put this is my cad program, and rotated the center bar in each illustration 8 degrees. After moving each bar, I could plainly see the bent ones get longer as they are raised. And they get shorter when going down. Not really to say they change lengths, but the arc does change. Try it with a piece of wire.

 

[2old2fast]

I'll try to explain ...if you start the arc w/ the pivot points at the same angle , the movement will be the same...in your example , the "bent" bars start at a much greater "real" angle ...

 

[2old2fast]

I'll try to explain ...if you start the arc w/ the pivot points at the same angle , the movement will be the same...in your example , the "bent" bars start at a much greater "real" angle ...

 

[choppedtop]

I know what your saying. In reality, the bent bars would be where the frame pivot point would have been at the top of the frame, with the rear end mount low on the housing. I am hard headed, and hard to learn I suppose. I will go to the shop and mock this up in real life. Be back with results later.

 

[choppedtop]

Okay John, you are correct daggumit. I made a straight bar and a bar with 45 degree angle. Both starting at the same frame pivot point. They swung almost the same arc, with the bent one swinging just a bit less. Thats with both bars level from start point, with up and down movement 3 1/2" each way. Thanks for making me work, and prove it to ME.

 

[old round fart]

That's OK Lee! Glad you figured it out! Thanks Jim. I think I'm going to use a drag style 4 bar witn a diagonal on the bottom bars. I may need that to harness a blown 454!

 

[Gerry]

And there you go......

 

[tfeverfred]

Thanks, that illustration explained how these work. Funny how something so simple can be a PITA.

 

[choppinczech]

That's OK Lee! Glad you figured it out! Thanks Jim. I think I'm going to use a drag style 4 bar witn a diagonal on the bottom bars. I may need that to harness a blown 454!

If I were starting over, I'd do that same thing. The best of both worlds. 4 link movement with lateral control.

 

[choppinczech]

That's OK Lee! Glad you figured it out! Thanks Jim. I think I'm going to use a drag style 4 bar witn a diagonal on the bottom bars. I may need that to harness a blown 454!

Ah, you mean like this.

 

[old round fart]

Ah, you mean like this.

View attachment 12501

That's it. Where did you get the picture? That one looks a little more street able than what I have been looking at.

 

[choppinczech]

That's it. Where did you get the picture? That one looks a little more street able than what I have been looking at.

(Photo Courtesy Chris Alston’s Chassisworks)

Techtips - Muscle Car Handling Upgrades: Rear Suspension System

 

[old round fart]

Looked there. Guess I missed it! Going back! Lol

 

[AusBucket]

G'Day All,
I have been a "lurker" for quite a while and wannabe rod builder for many years. I have been building Lotus 7 clones from scratch since 1999, and a lot of them including my current car use a Panhard Bar for axle location. The bars on our cars are something in the order of 4 foot long (right across behind the diff) I drew the bar for my first car up in Cad to gauge the side to side movement it placed on the suspension, and over 5" of suspension travel it only moved sideways by a little over 1/16"
It is important that the bar is horizontal at ride height, otherwise the axle will be forced sideways during suspension bump/droop depending on where it sits at the ride height of the car. It is a lot more difficult to place a decent length bar on a Bucket rear end, (due t the nature of the beast) so it becomes more critical to get it level and as long a practical. Just thought I'd join the conversation with what I have found on the cars I've been involved with.
I have now stopped building the Clubmans and would still like to put a Model a RPU together if I ever got the chance, it's a lot harder in Australia as building a new chassis from tube places the build into ICV status (Individually Constructed Vehicle) which then requires it to conform with current ADR's (Australian Design Rules) anyway, I enjoy reading about what all you guys are doing and following your builds.
Regards,
Mike.

 

[tfeverfred]

Good post from "down under", but my jury is still out on the bar having to be completely level in T Buckets. I'm thinking it's not that critical in these small cars.

 

[fluidfloyd]

Good post from "down under", but my jury is still out on the bar having to be completely level in T Buckets. I'm thinking it's not that critical in these small cars.

It should be level as lite weight cars with power react to small changes very fast in emergency conditions. To easy to just do it right to begin with. Just my position on the subject at hand Fred. Stay safe.
George

 

[fluidfloyd]

Ah, you mean like this.

View attachment 12501

Four bar suspensions that use diagonal centering links along with torque generating engines can and will cause torgue steer in lite weight cars. Had a customer running a 32 Ford with this setup and one of my fabricated rear housing. Call me and told me it really was pushing hard in one direction under the throttle. Gave him my opinion which he blew off so I told him to reverse the link left to right and call me back. He called back several days lather and said he had replaced it with a panard bar and life was go. Just something to think about. Have fun.
George

 

[AusBucket]

G'Day Tfever Fred,
Couple of reasons the bar should be level at ride height, firstly if it's on an angle it transfers the load to the chassis differently depending on which way you're turning. It's also true to some extent when it's level as the car corners differently right to left depending on which end of the bar is attached to the chassis. The other thing to be aware of is that with leaf springs the roll centre of the rear suspension is thru the centre of the diff , but with a Panhard the roll centre is where the bar crosses the centre of the diff, so if the bar is above centre it is raising the roll centre at that end of the car, and if the chassis end of the bar is above the diff end it can introduce a jacking effect which of course is an adverse reaction when you're trying to get the car round an obstacle or tight corner at speed. As I said in my earlier post I get that it's difficult to position a panhard bar on a Bucket or Roadster etc with the style of chassis and suspension most choose to go with, but it needs to be given quite a bit of thought.
Regards,
Mike.