pannard bar

[jerry shook]

Has any one tried the pannard bars on your A front or back. if so did you use the ones sold by snyder. do you like them.

[Mike V. Florida]

You might get additional responses from the HAMB site.

[Dick Deegan]

Jerry;

I have both front and rear pannard bars on my 30 Coupe. The rear pannard bar is very rigid from the frame to the banjo and will definitely keep the car from swaying. I installed it because of a vibration in the drive line. It turned out to be something else, but I think the rear pannard bar is good as an anti sway device.

The front pannard bar is a different story. It is supposed to also be an anti sway bar to keep the front wheels from swaying back and forth on a 'washboard" type road, especially if it is gravel. I have experienced this swaying on this type of road before with the A and it is not pleasant. You can lose control of the car very easily. However, the front sway bar to my mind is not rigid enough to do the job. The plate which mounts under the driver's side shock hangs down and the bar goes from the plate to the passenger shackle. The plate is very flimsy and can be moved by the bar very easily - thus defeating the purpose of the bar.

I would go with a rear bar, but not the front in its present form. If Snyder's comes up with a better arrangement, then I would go with both.

I bought both bars from Snyders.

Dick

[Purdy Swoft]

I installed the pannard bars from Snyders front and rear on our roadster. I think that the rear pannard bar helps the most. We like them, they help stabilize the drive in curves.

[Geo. H]

I run panard's front and rear on my roadster, but I got mine from AC&R, who are no longer in business. If I put an overdrive in my coupe, I'll be shopping for panards for it too. I think they're a great invention.

[RockHillWill]

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An anti-sway bar is generally a bar that is attached to the frame on both sides of the car and has an arm or a 90 degree extension of the bar that runs parrallel to the frame and is attached to the axle housing with a vertical link of some sort. It provides the 'anti-sway' characteristic by transferring some of the vertical movement from the outside wheel in a turn to the inside wheel in an effort to minimize the car wanting to sway to the outside of the curve, causing the body to 'tilt'

On a conventional solid rear axle and independant front suspension car you will traditionally find an anti-sway bar only at the front because the independant front suspension with its uneven upper and lower control arms contribute to a pretty large change in the front instantaneous link center making substantial changes to the front roll center center height. That contributes to a much larger weight distribution change at the front axle relative to the rear axle.

A panhard bar is normally fastened to one side of the frame at the rear and the other end is fastened to the rear axle. It's purpose is to keep the rear axle housings centered under the chassis. The opposite end of the panhard bar should be mounted as far from the attaching point on the frame as you can get. The shorter the bar the more lateral movement you will get any vertical movement. Lateral control devices have been used for a long time at the rear of cars with a spring device at each side of the car. There are a number of types. The affore mentioned panhard rods, both long and short, 'Watts' links, 'Jacobs Ladder' and others.

With both front and rear suspension devices (springs) running transverse left to right on the Model A's, lateral control is not an issue. It just seems to me that these bars being sold are a bandaid for a severe laceration.

It seems to me that good, well adjusted shock absorbers are in order!

It is very unclear to me how these bars are marketed, sold and used.

What am I missing here?

Just a thought!

[gweilbaker]

Pan-hards are a band-aid for soft or weak springs and worn suspension components, with such the axle assemblies can cause a pendulum affect side to side with respect to the chassis. This affect can cause for bump steer.

GW

[Ron/IA]

I agree that pannard (sic) bars geometrically cannot prevent sway. Panhard bars are used extensively in the racing industry to redistribute weight from wheel to wheel while cornering. Helping (along with other adjustments) to put equal down-force on all four wheels while negotiating the turn.

Keep in mind that the Model A traversed many more wash board roads in the day than they do now, and they did so without any problems. With suspension properly maintained and adjusted; the Model A handled such roads with ease.

I am for safety, and having the car handle the best it can; but when you add equipment to supposedly solve a problem-you are merely covering up the real problem. I always advise drivers to make sure their A's are mechanically adjusted and sound before trying any after-market parts. Ninety-nine times out of a hundred, there is no need for the bandaid.

[RockHillWill]

Good morning Gentlemen:

Panhard rods are used to keep the body located over the suspension, a minimal concern given the fact that both springs are mounted transversly. Anti-roll bars are more associated with restributing corner weights and and their 'balance' has a direct effect on oversteer and understeer.I am assuming this is not a serius concern for the Model A.

Bump steer is caused by different lengths of the upper and lower control arms along with a different length steering link at the end of a tie rod. When the one side hits a bump all three of these items move the same amount at the outer end, but due to the different pivot points they do not travel in the same arc, causing the wheels to point in different direction. The Model A has no upper or lower control arms and the steering is controlled by a fixed length tie rod. I am of the opinion that 'bump steer' is not an issue at all with the Model A for that reason.

Because the steering arms point to the rear and converge to the rear of the rear axle housings, there is some degree of Ackerman, I am assuming about 3 to 5 degrees. This cannot be changed by either a sway bar of a panhard bar.

I maintain these issues are all related to play in the suspension components, and not to any design flaws for which the Model A was intended.

These are just my current thoughts, and I am open to discussion because I always learn something .

I wish everyone a Merry Christmas.

[1931 flamingo]

Many "pages" have been written about bump steer on the HAMB, street rodder, other books, venues, etc. It's a gremlin that will bite you at the worst possible time.
Paul in CT

[MrTube]

Is that Bump steer, or Roll steer?

I was under the assumption solid axles typically had Roll steer, however, I may be mistaken.

[steve s]

Originally Posted by jerry shook

Has any one tried the pannard bars on your A front or back. if so did you use the ones sold by snyder. do you like them.

I've got the Panhard bars sold by AC&R (rip) on both ends of my '29 Town Sedan. I noticed a stability improvement on both ends but the installation of the rear unit made much more dramatic improvement. The feeling was of the car being more solid, more like a newer car.

My understanding is that they are needed with transverse springs because of the sideways movement allowed by the shackles connecting the running gear with the body; the body is basically hanging from a sideways swing. Whether that is a "minimal concern" or not I guess is a subjective judgement. The bars aren't so much intended to prevent "tilt" as they are lateral driftiness when momentum drives those two segments of the vehicle to go their separate ways in response to either unintentional road irregularities or intentional turns.

Another consideration that might matter to you is that they may interfere with the modern tube shock kits, in case you're getting really mavericky. I guess I could get along without my front Panhard, but no way would I be without the rear. But, what do I know?

Steve

[Bruce Lancaster]

Will, there are three basic motions going on under a car...
Yaw is turning, as in whole car goes thataway when you turn the steering wheel;
Sway is the car body/chassis moving straight sideways, that is parallel to ground, over its wheels/suspension;
Roll is car body/chassis leaning sideways over the suspension and wheels, that is body becoming not parallel to ground.

Obviously, most car movement involves combinations of the above.

Panhard bar is technically an anti-sway device, preventing lateral motion but not roll

The U-shaped across the car bars are almost universally called anti-sway bars but are not...they control ROLL and should be called anti roll bars. They can be hooked up to resist sway to a minor extent too by making links laterally rigid, but 99% of them are purely anti-roll

On Ford suspensions (pre-1942), it is critical that shackles at normal ride height be roughly 45 degrees to the world...as they move toward vertical from sagging or too long spring, they start to work like a hammock, allowing car to sway/swing from the shackles.
In 1942 or so, Ford went to long, more vertical shackles and soft rubber shackle bushings, but added sway/panhard bars fore&aft

[RockHillWill]

Bruce, I agree with all that you presented, in particular the shackle discussion. I had not taken that into account.

Why does it seem to show more effect at the rear? Would it be the difference in the arch of the spring?

I did learn something, thanks guys.

[Bruce Lancaster]

It may be a matter of altitude...just guessing at that. Rear shackles are way up there, front ones are down because of curve in axle. This all relates to roll center, likely, something I approach cautiously and with a reference book in hand! Adding anti sway device can relocate the point that is generally taken as the roll center, a concept that confuses me without a reference at hand!
One of the advantages of Ford springing is that spring width is out farther than can be done with wagon type springs, even on A front. After '34 Ford redesigned to make front spring even wider. This is why roll on a stock A is not bad.

[LukeDahlinger]

From my experience, a good set of original style shocks, properly installed springs & shackles and you won't need all that bolt on stuff.

It's quite surprising to see the number of Model A's on the road with no shock absorbers or disconnected shocks because the old Houdaille is froze up.

[Kevin in NJ]

The Model A with good springs is horrible to drive without proper working shocks.

Most of the guys without shocks are also driving on flat unlubricated springs and stay under 45 MPH.

With a properly set up A the 4 wheel guys look at you funny as you pass them in the woods or the road.

[Larry Brumfield]

The Ford engineers were satisfied and had no problems with the Model A's handling characteristics and would have never even installed shock absorbers had it not been for Henry Ford's direct order. He drove the Model A across a plowed field and said upon returning, "Rides too hard. Install hydraulic shocks."



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[redmodelt]

If the pannard bar is mounted to the center of the axle at the diffy housing and to the out side of the frame, and if the axle drops straight down or moves straight up would that not cause the body to move side ways to the left or right following the arc of at the end of the rod?

[MikeK]

Originally Posted by redmodelt

If the pannard bar is mounted to the center of the axle at the diffy housing and to the out side of the frame, and if the axle drops straight down or moves straight up would that not cause the body to move side ways to the left or right following the arc of at the end of the rod?

Yep, but it is a smaller movement than the side-shift as the shackles sway when the body rolls with one side of the traverse spring in linear compression, arching higher, and the opposite half stretching, flattening out. There have been complicated lever arm mechanisms designed to overcome the limitation of which you speak, but nothing beats the simplicity of a pan bar with just two attachment points and two joints.

If you eliminate body roll, you eliminate the problem. Not so easy with just one traverse spring on shackles front and rear. Adding a torsion bar to control roll will make a mess out of an A if you wish to maintain a relatively stock appearance.