Leaf spring woes...

[WrenchMonkey]

Originally Posted by gothodgie

looks almost like some old school traction bars...

Yep, that's exactly what there are: a homemade, offroad version of the old Lakewood traction bars:



That is, of course, why I just had to paint them yella!

Robert

[Coppertop]

Looks good Robert...I'm curious to see how they perform offroad.Yella traction bars bring back some great memories.I had a set on my 69 cougar.

Nick

[adamkn]

Hey Robert - good to meet you last weekend at Big Rock! So, what happened with your Jeep?

[WrenchMonkey]

UPDATE:

I just realized I never posted back to report how these worked offroad. Bluntly, they didn't. Not at all.

I had less traction and more wheelhop than I ever had before, to the point of destroying the old leaf packs. I sheared the centering pin, separated the leaves, and had to strap the axle in place to limp it out of the park.


Now I had suspected at the time that I might have issues:

Originally Posted by WrenchMonkey

There's probably a dozen reasons nobody has done this, and a dozen more why it won't work like I want...

...but I never understood exactly why it went so badly, especially when it seemed to work so great on the street. Til now.

I've been doing some suspension research lately, playing with ideas for the Willys I'm gonna build "one-day." And I now realize that what I built way back when was essentially a crude radius-arm. And I had given myself a clue to the impending doom when I wrote:

Originally Posted by WrenchMonkey

But I swear I can feel the antiwrap working, too. When I get on it, the ass end tries to rise a bit as it puts the power down.

That wasn't "antiwrap" I was feeling, that was antisquat. And crazy antisquat numbers are why nobody uses a radius arm rear suspension.

I had heard that term, antisquat, but I never understood it. Now I'm learning. Basically, the torque of the rear axle, that previously caused axlewrap, was now being delivered to the bottom of the jeep, actually lifting it slightly.

On pavement, this was okay. The bar pushed up on the body, the weight of the jeep pushed back down, the tires dug in, and off I went.

But offroad, the limited traction threw everything into chaos. Since the rear tires were now trying to actually lift the weight of the jeep as well as trying to move it forward, I was fighting against myself. I would have needed more traction to climb the same hill.

And when that traction wasn't there, really bad things happen. The tire slips, the torque is removed from the bar, and the lifting force vanishes. The body of the jeep drops back to and then below ride height, flattening and even inverting the leaf. All in a split-second of violence. (There's a name for this, too, that I'd heard but never really "got": Unloading.)

Immediately, the suspension bottoms out, the tires dig in, the traction returns, the axle rotates, the bar lifts the body, and the cycle repeats. And chit breaks. Bad.


None of this really matters now, I put a new set of leaves in it right after this failed experiment three years ago.

But for future reference, in case anybody else considers it, this is why my idea didn't (and won't) work...

So don't try this at home.

Robert