[CSGAS]

Beetle,

Shorty's second set of photos show the ladder bar setup.

In concept, a ladder bar suspension and a trailing arm setup (like our truck arms) are the same arrangement; consisting of links directly attached to the solid or live axle which moves up and down, some locating method to prevent side-to-side movement, and forward pivot mechanisms to connect the assembly to the chassis.

In application, ladder bars are generally used when higher strength is required ( note the hefty tubes) and usually get a straight forward-to-back geometry instead of being pointed towards the middle of the chassis at the front like our truck arms or "split wishbones" or other more "civilian" applications of the approach are.

Also, ladder bars end up usually welded to the axle instead of bolted (there are exceptions) and the most accepted locator is a diagonal "triangulation" bar running from the lower rear attachment point on one side all the way to the front pivot point of the other side; instead of a track bar.

This arrangement shows it advantages in straight-line driving, since independant movement of the left and right ladder bars is generally limited if possible at all. The geometry of the front pivot points works to aid transfer of weight to the rear axle area, to aid traction. As a general rule, the lower the pivot points are and the longer the bars are, the better.

If you are building a chassis from scratch or for a leaf-sprung ride that you intent to race or exhibit, ladder bars are a respectable setup. If you want a dual-purpose ride or you already have a truck-arm equipped ride, I'd suggest mods that make the truck arms behave like ladder bars instead since they can take a bump in the road on just one side of the truck, or turns, or...

...Mods like this include boxed or tubular bolt-on truck arms; with large hiem-joint, monoball, or custom bushed front pivots points; relocated front pivot points (many shops sell plates with slotted or multiple holes); adjustable coil-overs; a Watts-link setup instead of a triangulating bar (since street driving is the reason for my rambling) and downtubes from a roll cage to a point just above the axle to help the weight transfer go where it's supposed to.

For a (presumably) lightweight trailer queen, ladder bars would also need the downtubes and usually use coilovers. While it seems like they should be available to bolt into the stock truck arm mounts, that would cause binding and geometry that defeats the usual purpose of having full ladder bars. The truck-arm crossmember can still be used to mount the ladder bar pivot plates (which are also available with multiple holes for adjustments) further outboard for that straight alignment. A lot of study of your particular setup and creative engineering into the relationships is required to make sure the vehicle launches straight and hard. A drivetrain that shocks the chassis hard--like a transbraked setup--compliments this best. It's not as hard as jumping into four-links would be, and once you learn ladder bars you have a head start on understanding four-links at least for straightline acceleration. It's perfectly acceptable to need to rework it a couple times to get it right...as long as you don't kill yourself trying it out the first time!!! Have a mentor look at your particular application a few times throughout your installation and shakedown.

There are other uses for ladder bars, where strength is needed--heavy-duty trucks and some stunt cars, for example. I haven't seen FF4 yet, but I'd venture a guess the ladder bar-equipped truck had some high jumps or really rough obstacles to get over, or maybe a drifting skid that would have turned a truck arm into a pretzel.

Your local dragstrip pits on a bracket-racing weekend would be your best place to see ladder bar installations you would like, or some Nostalgia Gasser cars.

Hope you end up with whatever really makes you happy!