Panhard, Diagonal Link, or both with ladder bars?

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Jhenry70

Jhenry70

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Quick question, and hopefully not too dumb of a question...

My 72 Duster was purchased as a shell pretty much. One of the PO's had already started the BackHalf on it when I took it over. I'm really just going for a nice street rod that can be driven around town to events and shows and may possibly hit a track a couple times a year (enjoy the drags but not really my priority).

As I'm getting close to finishing up the drive train and now have the rear under the car... It's a shortened 8.8 with 4:10's, posi and disc brakes, I'm wondering about my side to side movement and if the Diagonal link that I have is the best way to go for more of a street car? I'm a newbie to ladder bar suspensions and I'm learning as I go. As I try and do research I see different cars out there that have either the Diagonal Link or a Panhard Bar by themselves and occasionally I see setups with them both.

What do you guys think? Should I just stick with the D Link by itself, or is there any harm or any added benefit to also installing a Panhard Bar as well? I know I'm going to have a rougher ride with the ladder bars over a spring setup, I just want to make sure it's safe and as much worry free as possible.

Here's a couple of pics... The rear sitting on the lift and you can see the D link, and a pic as it's being fitted under the car.

image (1).jpg


image.jpg


rear.jpg
 
it is gonna ride....like a race car.

the D link works fine for a locator, but IMO it is more on the race car side....I would not do both, the diagonal link functions different than a panard bar. I have never seen both on any car, I would think they would almost work against one another.
 
A Panhard rod is going to give you a far better lateral locating function; it is acting much more directly and small flexures don't get magnified like the diagonal.

As said, I would not use both; I have not worked out the geomettry, but would expect them to track quite differently with vertical motion and would fight each other and bind against one another.
 
A couple of chassis guys have advised us on my son's ladders. Both said the same thing, diagonal for drags not strong enough for street, panhard is for circle track cars, use a wishbone for the street.
 
Coronet 500 said:
A couple of chassis guys have advised us on my son's ladders. Both said the same thing, diagonal for drags not strong enough for street, panhard is for circle track cars, use a wishbone for the street.
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I built an ex "don hardy east texas racecars" vega, w/ a real hot 406 sbc in it. it had ladder bars-tubbed- w/ a panhard bar, all built by east tex. racecars. . other wise a basket case w/ no baskets. the trick is to keep the panhard bar as " level as possible ", w/ no binding, so it doesn`t push or pull in the suspension travel. which probly ain`t gonna be much w/ coil overs and ladder bars. I had 14-32.5`s on mine and drove it on the street a lot. didn`t ride real good, but sure got a lot of comments, and would smoke a callaway corvette or a porcshe. " up to a certain point!"
 
Thank you everyone for the information, that's exactly what I was looking for. Looking back at my original post I should clarify that the ones I saw with both were more pictures of some suspension kits that showed both, maybe they were optional with what ever way you wanted to go? I'll stick with the D Link for now, get it all set up and squared and see how she performs.

What really got me thinking was reading a lot of tech stuff on ladder bars for dropped/bagged trucks and rat rod style builds. Some used the four link and others used the ladder bars but one thing that was pretty consistent was the use of a panhard bar. If I ever wanted to switch from the D link, the panhard bar route seems pretty easy as for making brackets for the 8.8 and I should have plenty of clearance to the frame rail for the other end.

I appreciate all the feedback!
 
One more thing on the panard......
make it as long as humanly possible.

The longer the panard....the less lateral movement there will be
 
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HemiDenny said:
One more thing on the panard . .
.make it as long as humanly possible.

The longer the panard....the less lateral movement there will be
Click to expand...

So, if you were me, which way would you go for a mostly street car given the fact that's already set up with ladder bars and coil overs?
 
If you want to soften the race car ride you could replace the heim ends with a rubber bushed end like Detroit Speed and Engineering sells.

I would also replace the diagonal with a long rubber bushed panard bar.

If you decide to head to the race track...put the heim ends back in all around.

Still will not be a cushy as leaf springs but it will take 50-60% of the harhness out.
 
HemiDenny said:
No ....those IMO do not give much cushion and you will hardly notice any difference from a regular heim. The ones for street I suggest are rubber bushed. I will dig them up later.
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I don`t think I`d use rubber on the panhard bar, probly good advise on the rest tho. I didn`t have room for any lateral movement on mine.????????
 
HemiDenny said:
No ....those IMO do not give much cushion and you will hardly notice any difference from a regular heim. The ones for street I suggest are rubber bushed. I will dig them up later.
Click to expand...

I looked at those last night as well... States right on the description NOT to use these for any steering and or suspension 3 or 4 Link set ups.

I'd be interested to see the ones you are talking about HemiDenny... I looked at Detroit Speed briefly last night but didn't see where you could purchase the ends separately.
 
I'll correct one thing: Panhard rods are NOT just for circle track cars. They have been and still are production items on some RWD vehicles, and were used successfully on most or all of the successful RWD rally cars in the 70's and 80's. My 70's vintage Opels all came with them from the factory and had a very good rear live axle suspensions, as well as my 2016 RAM pickup (where a panhard rod comes with certain options).

Yes, use the rubber bushings for sure; it will avoid breaking stuff if you kiss a curb. The chassis mount has to be good and strong.

MOST importantly! Study up on how to locate the end points of a panhard rod. THAT sets the rear roll center height above ground for a live rear axle. You can make the locating points variable (typically by using a series of vertical holes in the chassis end connection) and use that to adjust the rear roll center height. You can use that to tune in the F/R cornering bias (just like they do with an adjustable track bar). It will also be useful to have the chassis end connection point adjustable so that you can change rear spring height and then independently set rear roll center height.

Note that it is normal to have the rear roll height a bit above the front roll center height, but not TOO much higher, so some work at figuring out the front roll center height is in order. A and B body stock front roll centers are often at, or even a bit BELOW, the road surface, so if you don't pay attention to the rear roll center height and get it high, the rear is going to want to wag and roll the car all over the place. I have some calculations somewhere.....lemme know if you want further info. (It's not exactly rocket science to figure out.)

I would be looking at using a tubing diameter in the 1" to 1-1/4" range.
 
Jhenry70 said:
Rod Ends

Speedway, Speedway Suspension Rod Ends - Free Shipping @ Speedway Motors
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no...but Summit carries them, from Howe,
I got the ones (just like Summit sells) on my silver Duster from Detroit Speed years ago. NOW, they have their own swivel link....and they are pretty proud of them. Two rear lower bars...$400

I use the rubber bushed on my panard bar also....best I have found.
https://www.summitracing.com/parts/...-howe-racing&gclid=CODQw72099ACFdK6wAod5qsDaQ
 
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HemiDenny said:
no...but Summit carries them, from Howe,
I got the ones (just like Summit sells) on my silver Duster from Detroit Speed years ago. NOW, they have their own swivel link....and they are pretty proud of them. Two rear lower bars...$400

I use the rubber bushed on my panard bar also....best I have found.
https://www.summitracing.com/parts/...-howe-racing&gclid=CODQw72099ACFdK6wAod5qsDaQ
Click to expand...

What's the width on those? I didn't see it in the description. They look way wider than the heim joints with the pivot spacers. If I were to go with these it looks like I would have to refab the front frame connector for the pivot. Do you use pivot spacers with them as well?

6263_3_.jpg
 
nm9stheham said:
I'll correct one thing: Panhard rods are NOT just for circle track cars. They have been and still are production items on some RWD vehicles, and were used successfully on most or all of the successful RWD rally cars in the 70's and 80's. My 70's vintage Opels all came with them from the factory and had a very good rear live axle suspensions, as well as my 2016 RAM pickup (where a panhard rod comes with certain options).

Yes, use the rubber bushings for sure; it will avoid breaking stuff if you kiss a curb. The chassis mount has to be good and strong.

MOST importantly! Study up on how to locate the end points of a panhard rod. THAT sets the rear roll center height above ground for a live rear axle. You can make the locating points variable (typically by using a series of vertical holes in the chassis end connection) and use that to adjust the rear roll center height. You can use that to tune in the F/R cornering bias (just like they do with an adjustable track bar). It will also be useful to have the chassis end connection point adjustable so that you can change rear spring height and then independently set rear roll center height.

Note that it is normal to have the rear roll height a bit above the front roll center height, but not TOO much higher, so some work at figuring out the front roll center height is in order. A and B body stock front roll centers are often at, or even a bit BELOW, the road surface, so if you don't pay attention to the rear roll center height and get it high, the rear is going to want to wag and roll the car all over the place. I have some calculations somewhere.....lemme know if you want further info. (It's not exactly rocket science to figure out.)

I would be looking at using a tubing diameter in the 1" to 1-1/4" range.
Click to expand...
Agreed 100%. Heck, my 2008 Wrangler has a panhard bar, front and rear. And my SRT8 Durango has a 4 link parallel watts link suspension directly from the factory. And If i recall right, most new mustangs are running some type of panhard/track bar on their rear suspensions.
 
mopowers said:
Do you run those on the front mount and the rears, or just the fronts?
Click to expand...

I only have the in the fronts right now....but when time allows, I will put them on the rear of the bar also.
Had heims....then poly with no tell-tale difference...Finally the rubber.THEN, I noticed the difference.

I plan on making a complete separate set with rubber bushed on all four ends and put all heims back in the bars I have now for trips to the strip. It is a lot easier to change the whole bar (one at a time) then swap the rubber for heims.
 
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Jhenry70 said:
What's the width on those? I didn't see it in the description. They look way wider than the heim joints with the pivot spacers. If I were to go with these it looks like I would have to refab the front frame connector for the pivot. Do you use pivot spacers with them as well?

View attachment 1714998461
Click to expand...

Looks like a safety piece in case the end brakes. The rubber bush ends are wider than a std heim.
 
HemiDenny said:
I only have the in the fronts right now....but when time allows, I will put them on the rear of the bar also.
Had heims....then poly with no tell-tale difference...Finally the rubber.THEN, I noticed the difference.

I plan on making a complete separate set with rubber bushed on all four ends and put all heims back in the bars I have now for a trips to the strip. It is a lot easier to change the whole bar (one at a time) then swap the rubber for heims.
Click to expand...

Since the rubber bushings are so much wider than the standard heims, do you set it up for the rubber ones and just use spacers when you swap to std heims?
 
Spacers.....very common....if needed, however, I will more than likely for the ease of it, use the wider mis-alignment heim

When I built /fabbed it I made it wide on purpose....never know what you may want to do in the future.
 
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HemiDenny said:
Looks like a safety piece in case the end brakes. The rubber bush ends are wider than a std heim.
Click to expand...

Yeah, I have a different safety hoop on mine... The Pivot Spacers are outlined in the pic below. These go in the front bracket holes and have a shoulder on them so when you tighten down the nylock it doesn't crush the bracket and pinch the heim joint at the pivot point. My front brackets for the ladders were already heavy welded in when I got the car. If I were to use the rubber bushings in the future I'll have to refab that bracket to be wide enough to accept them.

This has been very informative for me, thank you all for participating!

Jerry

6263_3_.jpg
 
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