[mrtzmd]

Hello, i saw an adjustable panhard rod for the GT on ebay and i am not sure how these work. I was hoping someone could comment on them. Thanks.
Mauri

 

[Travis]

Could you post a link? I took a quick look and all I found was the Watts linkage discussed in some other threads, which is neither a panhard rod, nor adjustable, though it does take the place of the panhard rod.

In general, an adjustable panhard bar is both height and length adjustable. Length allows you to adjust the axle position left to right and height allows you to both level the bar(parallel with the ground) as well adjust it's overall height to change the rear roll center. Changing the rear roll center provides fine tuning of the oversteer/understeer characteristics of the car.

-Travis

 

[G.v.Mainberg]

Panhard

Travis,

how do you adjust a panhard rod in its height? Its pretty obvious how the length adjustment is done (shorten it --> axle offests to passenger side, make it longer --> axle offsets to driver side), but I would't have an idea what other adjustments you could have with a simple rod.
BTW - the mentioned Watt linkage is a GREAT way of improving handling in fast corners. The current ebay item will end in a few hours, and I'm eager to see the highest bid - it might be mine!

Dieter

 

[Travis]

Travis,

how do you adjust a panhard rod in its height?

It's actually the mount that adjustable, not really the rod. If you look at my Toyota axle conversion you can see the adjustable mount in the fourth pic down

http://users.adelphia.net/~tlwoodbury/axle.html

You'd also need to do the same or similar thing at the body. RallyBob posted a pic a few years back that showed the body reinforced and slotted...

BTW - the mentioned Watt linkage is a GREAT way of improving handling in fast corners.

While technically superior as it allows perfect up and down movement of the axle, the actual performance gain will vary greatly depending on the application and the lack of adjustability could actually be a hinderance

In my application, where I have very little suspension movement, both in bump and roll, the 'arc' movement of the axle due to the panhard bar is VERY minimal, especially with the longer bar I'm running. If we we're talking about a car with large amounts of suspension travel, the story might be different.

-Travis

 

[nobody]

This one is being sold for a Holden but the idea seems pretty clear.

 

[jeff denton]

Somewhere there is a thumbnail pic of how we did the panhard bracket on Speedway GT. Very simple, we gave it about an inch of adjustment each way from stock hole, probably way more than we'd ever need. On our Limited Late Model Thunderbird we occasionally move it up or down, never more than 1/4 in. Seems like the driver never likes it and we put it back where it was.
When lowering the ride height of the GT by whatever means (we made the spring buckets deeper) the panhard bar would absolutely have to be adjusted accordingly!

 

[mrtzmd]

adjustable panhard rod on German Ebay

Travis, here's the artical number on German Ebay for the adjustable panhard rod:
4514590729. Thanks
Mauri

 

[Travis]

Looks like it's setup for stock sized bushings, which would allow use of the OGTS poly bushings. Unless your axle is out of place due to lowering the car, it doesn't really have any advantage over the stock bar. In the case where the car has been lowered, you'd want to make the mount on at least one end adjustable, and if you're already fabricating some parts, just fabricate the bar too and save some cash. Those who don't have the fabricating tools or skills should be able to find a local welder who'd be willing to do a little fabrication

-Travis

 

[mrtzmd]

Thanks Travis for the info. My Gt is for mainly street use so i think i will stick with the stock bar. Mauri

 

[The Scifi Guy]

As per Heimue's post earlier on, I too am interested in finding out what the adjustment standards are for an adjustable panhard rod. I understand that the arc movement of the rod shifts the rear suspension right or left. I've only recently become aware that using the recently available lowering springs can cause this suspension shift.

I'm a little concerned recently because I detected a little sideways "push" at the rear end when applying brakes pulling my trailer. I have the lowering front and rear springs.

Out of my home garage, how would I measure or calculate the proper adjustment of an adjustable pan hard rod? Wouldn't I need to do the adjustment at an alignment shop while sitting in the car with a full tank of gas so that the weight is correct and stuff? What home methods are there for getting the adjustment done?

 

[hrcollinsjr]

Out of my home garage, how would I measure or calculate the proper adjustment of an adjustable pan hard rod? Wouldn't I need to do the adjustment at an alignment shop while sitting in the car with a full tank of gas so that the weight is correct and stuff? What home methods are there for getting the adjustment done?

Alignment shop would be the best way to do it. They might or might not let you sit in it for the alignment. If not, a big bag of crap could be substituted of approx. the same weight as you and a 1/2 tank of gas.

Harold

 

[opelspyder]

If you like sitting in your car all day long, and having the panhard bar adjusted 8 times, there is an alignment guy in Chapel Hill, TN that can get you fixed up in a shade past a day!!

 

[P.J. Romano]

Gordon, it pays to take the car for the professional alignment. After I installed new difficult to find 285/40-15 tires, I took the car for the wheel alignment. My rear trailing arms are also adjustable and I wanted to be sure that the tires will not be worn out during long trip to Carlisle and back. It took the technician about 1 hour, I was encouraged to sit in the car and it cost me $101.67, including tax. They gave me computerized printout with all measurements before and after alignment. Well worth that money and time.

 

[GoldGT]

Hmmm....I must be too low tech for this one. My car does not have adjustable trailing arms so I only have the adjustable panhard bar. All I did was let the car down, rolled it front and back a little adjusted the bar until it was neutral and tightened it up. My car tracks straight as an arrow. I dunno :dunno: it just worked. Lucky maybe.

 

[G.v.Mainberg]

For adjustable trailing arms, I suggest a professional alignment so your rear axle is not pushing to either the left or right side. For the regular, non-adjusting arms, you do not need this. If your car ain't going straight, your frame is bent which is something you do NOT want adjustable trailing arms to compensate for.
An adjustable panhard rod gives you the possibility to adjust your rear axle more to the left or right, which is specifically good if you change the ride height of your car (eg. lowering springs). Measure the distance from the outside of the rear wheels to the wheel archs, and adjust until this distance is about the same. If in doubt, leave a little larger distance on the driver side. While the suspension is compressed (while driving over a hump), the panhard rod moves your axle a little more to the left anyway. Now as a different example, the panhard bar on my Jägermeister is almost horizontal due to the fact that it is lowered so much, my rear axle moves almost exactly up and down.
The adjustment of a panhard rod has no influence of your rear axle pushing the car to the left or right. The car will always drive straight.

Dieter

 

[wrench459 (R.I.P.)]

... The car will always drive straight.

If the thrust angle is off ..it will crab.

 

[broszzy]

what does the pan-hard bar do? pulls the rear end left or right.
Weight it down and Measure from the top of the wheel to the same place on both sides of the wheel well and adjust it halfway.

Pat

 

[Yellow73GT]

what does the pan-hard bar do? pulls the rear end left or right.
Weight it down and Measure from the top of the wheel to the same place on both sides of the wheel well and adjust it halfway.

Pat

Actually, the pan hard bar helps center the rear end in relation to the vehicle chassis, but due to the fact that a bar attached at one point to the rear and one point to the chassis tends to swing in an arc, it really depends on suspension travel during compression and deflection as to how far the bar will "pull" the rear one way or the other. Also as noted, if you lower the car or inversely raise it (ie lifted four wheel off road vehicles for example) you need a bar that can be adjusted to compensate for the change in height. Ideally your mount points on the pan hard bar, at both ends, should be such that they create a parallel line in relation to the rear end. Otherwise, depending on which side of the arc you are starting at at normal ride height, the rear will tend to want to move more dramatically than if the bar were level at normal ride height. For example, say we have a lowered Opel, if all you do is install an adjustable pan hard bar, and do not alter the mounts (yes, you can do this but it is not the IDEAL way) then when the car hits a bump that causes the rear to rise in relation to the chassis, it will cause the rear to also "pull" to the chassis mount side more than it would have had the mounts been level, because it is farther along the arc at the start point. So if you can move the mount points you can limit this effect, also the longer a bar the less of an arc it will swing in (to a point). Unfortunately you are limited by the width of the vehicle and or rear end for deciding over all pan hard bar length.

This is really an oversimplified description, so I have included a small crude paint drawing to better help anyone who may not understand, please forgive the crudity of my drawing. The blue bar would be the pan hard bar, the red line shows the arc that the rear end attachment point of the pan hard bar swings through.