Track-Bar Questions

[PrimeredThunder]

For refrence I'm running a 72' Chevy SWB with trailing-arm suspension and no suspension notch on airbags...

My questions are regarding the tracking/panhard-bar. I havent swapped out my stock unit, so i'm getting some massive side-to-side axle movement in my suspension cycle. I want to know if I can modify my stock bar in the stock location to resolve this? I would think lengthening it to the appropriate length so my axle is centered at ride-height should solve the massive amount of travel? Or would a "Super Track-Bar Kit" from say ECE with the relocater brackets work best because the length of the bar? I'm trying to keep this as cost effective as i can, but then again, there are some things you shouldn't be a cheap-skate on...please shed your light on what i should do, any pictures of your track-bar setups would be great too for refrences. Sorry for rambling..i get a bit carred away at times

Kenny

[Slammed67]

Ideally, you want the bar to be as long as possible and horizontal at ride height. Here is a pic of my ECE track bar (before I added air bags). The left side of the bar mounts in the stock location. If you have the money, I'd recommend the ECE track bar or something similar. Keep in mind though that the ECE bracket won't work if you eventually notch the frame, and I assume you will (see second picture).

[SWEET7T]

I agree with Slammed67, the longer the bar, the less side-to-side movement there will be.

[MrShelley]

Maybe this will help explain the relationship between suspension height and tracking arm length.

[MrShelley]

forgot pic

[MrShelley]

Pythagorean theorem....geometry works, spelling not so good

[PrimeredThunder]

Thanks for the diagram...now...any ideas where to mount it? I was thinking building a bracket for the Drivers side trailing and then mounting the other end on the pumpkin? Then lengthening the arm for my drop?

[Slammed67]

My suggestion.......... Mount one end to the stock location (on the driver's side frame) and the mount the other end to the passenger side trailing arm.

[MrShelley]

My ECE Super Track Bar Kit mounts in the factory location on the driver side and on top of the passenger trailing arm.

I had to extend my notch on the passenger side to clear it, but it works well.

[jamis]

Mine is on the drop block or mount it as Slammed67 or MrShelley
say.

[PrimeredThunder]

Jamis-I really like the way you made that mount. Did you just weld and drill the two pieces to the block? How does it fit (clearance)?

[jamis]

The lowering block is welded to trailering arm and the track arm brackets are welded on to the block. The clearence is fine with a normal c-notch, but if you dont use the block then the track arm bracket must be welded to the trailering arm as slammed69 said.
MrShelley's idea is also correct, to use the ECE kit you must make a longer c-notch. All three of these ideas will get you the same result.

I did mine this way beacuse I wanted a 7" drop using 5" springs and 2" block. I first tried it wuth just an adjustable track arm in the stock position, but it dint work right. So I fabricated my current set up.

If you need some more pictures let me know

[PrimeredThunder]

Jamis, please send me any pictures of your setup. I think I'm going to mount the bar at the stock location and fab a mount on the pass.side trailing arm. Do the mounts need any bushings for the bar? Or is a bolt and some washers good enough?
Kenny (maxximus72@hotmail.com)

[jamis]

Just a bolt, the bushing is on the trailering arm itself. I will post some picks tommorow when I get home.

[jamis]

I couldnt e-mail them, I will try I again later as soon as I can.

[jamis]

2

[jamis]

This pic is from Slammed67's truck, I think this is what your looking to do. Hope Slammed didnt mind me snagging his pic.

[PrimeredThunder]

Exactly! Any idea what to us to lengthen my stock arm? I think I'm going to use the ends and just cut some tubing that will fit around the ends and weld it together with some new bushings. Thank You once again, you've been a great help!

[jamis]

that should work just make sure the tubing has 1/4 inch wall thickness. AS far as the lenght goes your going to have to measure that yourself after you make the brackets. every truck is going to be diffrent. Make shure you weld the trailering arm bracket in line with the bracket on the frame so you wont have any bind

[greatdaen]

The panhard rod design has the limitation that all of this thread discusses - it is a fixed length bar so its free end will follow an arcing path. You can make it longer and change the mounting locations, but your axle will always be translating the arced path.

For that reason, I prefer a modified Scott Russel link. I don't know if anyone offers these as kits. I have always built from scratch.

I have attached a CAD drawing showing the Axle motion with the SR link.

In a true Scott Russel mechanism, the small link at the left end of the long rod is replaced with a slot/slider type setup. That is a little too messy for this application. The use of the short fixed-length rod causes very little degradation of the motion.

At the left end of the long rod, you'll see a dashed curve that shows the motion a panhard rod travels - and that of your axle! This example is a little more extreme for a couple of reasons. First, the at rest position of the long (panhard) rod is not vertical. Second, this example shows a rather large amount of travel - nearly 20 inches vertical. Most stock suspensions are in the 10" and less range.

The beauty of this system is that the Right hand pivot on the axle travels in a straight line vertical motion. And since the axle is a solid member, the whole thing has to travel in a straight line.

If you build one, you can vary the length of all the members. The center pivot in the long rod (panhard) ideally should be in the same vertical plane as the pinion.

Food for thought. Anyone up for building one?

-dch

[greatdaen]

OOPS!

In above post:

"This example is a little more extreme for a couple of reasons. First, the at rest position of the long (panhard) rod is not vertical. " ... should read "horizontal"

-dch

[XXL]

SR links and other more sophisticated geometries are a little excessive for what the OP is asking about. For the amount of lift and drop differential we're talking about on these trucks (especially without a frame notch), a Panhard bar config will suffice. Having said that, I still recommend the Super Track Bar kit as the extra length reduces the axle deflection even more. I haven't done the math, but I'm guessing there's less than 1" of side movement in my truck from full-up to dumped... and I've got a frame notch.

No reason to make it more complicated than necessary, especially given budgetary constraints.

[greatdaen]

What is the length of stock arm pivot-to-pivot and the Supertrack arm pivot-to-pivot? What is your suspension travel from rest in jounce and extension?

I would like to do a little math...

-dch

[ucmydust68]

how much does the ece super track bar run????

[Slammed67]

I think the stock bar is about 24" long. Not sure about the super track bar length, but it goes from the stock mounting point on the driver's side over to the top of the trailing arm on the passenger side. I'll have to measure mine unless somebody beats me to it.