Technical My First Straight Axle

jrblack30 I'm in the Finger Lakes near Ithaca

 

More like Lower Searsburg! Hahaha

 

Interesting article on dual quarter eliptical springs. Couldn't find any follow up though...
https://www.hotrod.com/articles/dua...ndy-will-they-work-on-san-fernando-boulevard/

 

Here's a bump to the top for the morning crowd.

 

Research a little on torsional stress on round tube axle, the Ford beam axle could flex without bending or cracking, you can see it moving on open fendered cars, but not so with a tube axle, thats where a hairpin radius rod is commonly used.

 

I'm more and more convinced that the real death wobble problem was the toe out that tends to occur with positive scrub radius. With the spacers required to run our 35 wire wheels on the 48 drums we have excessive positive scrub radius. If you put a little toe in in the front end and your scrub radius causes toe out, you'd end up neutral/slack. With all the other issues with that front end slack steering gear is just waiting to wobble.... I Think! Anyone have a solution for running 35 wires? WITH brakes.... Can you get offset wires? We want the wires even if we have to build our own disc brake system....

 

6 deg caster, 1/8 in toe in, ditch the wire wheels, put Solid Steel wheels, I had the same problem on a 27 T the problem was the wire wheels, they flex and don't stay true either way. can be oval and or have severe flex on turns.

 

I wouldn't trust that set-up to drive around the block. No straight axle expert, but springs alone is not a way to mount a straight axle.

That setup is going to have alot of variable caster, under load, the axle is going to tilt forward.

Really should be hairpin or wishbone mounted.

I also would think that's way too much load for just leaf spring mounts, one of those snapping off is going to be a bad day.

 

those 2 leaf springs work same as hairpin or wishbone. Any of them break & u got problems. Keep working on fine tune of what you have.

 

Ditch the wheel spacers and run 55 F100 brakes. Pull the center contact patch to the point where a line drawn through the center of the king pin would contact the ground.

Having built jeep's for decades the situation you have is a sure fire recipe for death wobble.
Loose bushings
Ackerman issues
Wheel spacers
Limited camber
Narrow track width
No positive axle location either sideways or back to front.

 

No, those do not work the same as hairpins or wishbones.

This swings like a 4-link rear end. Hairpins and wishbones keep a fixed angle at the axle, and the whole axle assembly pivots at the rear hairpin/wishbone mounts.

There are 4-link front end setups, but they use radius bars and springs, not just springs, and the bars are much longer than the springs on this setup.

18" 'radius' springs will never ride or drive like 3 foot split wishbones, hairpins, or 4-link.

 

We decided we'd better be sure the rear was straight and solid before tackling the myriad of issues we have up front. We found a panhard bar at an angle that pushed the axle sideways on a bump. It is now straight, centered, and solid. We have the front axle on the table now.

 

Glad to see the update. Keep us informed with pictures.

 

Looking good! New tires?

 

Good eye. Bit taller tires, and moved the axle fwd inch and a half. New stance!

 

Willys in my avatar has quarter elipticals in the rear with big ladder bars and a long pan hard across the rear of the diff....not much movement, good for hookin' up! Not sure I'd run a front setup like yours tho....

 

I'ma jumping back in again.
This at best is a mess. Four leaf springs and probably four different rates. That'll never work. Combined with rubber bushings and no panhard rod...all be like four flys in a mason jar, zig zagging trying to find stability but never.
I'm sure a good chuck hole translates to "hang on Martha we're going for a ride".
I can't see castor adjustment. Needs to be rigid...and 5-8 degrees. That's what makes the front end track straight. Positive camber not good but might have to put up with it with solid axle. (Sprint cars no positive camber). It can be changed.
Toe...out for race cars, in for street. Both will compress slack in joints. But you can confuse it and cause a wobble when chuckie hole is encountered.
As said before....untrue, wobbly wheels...no brainer.
All needs to be square and true to centerline of chassis.
One final note, on these types of suspensions all panhard rods, wishbones, steering rods all need to be as long as possible. Short stuff makes for a chop- chop ride.
My tarnished penny's worth....

Sent from my XT1710-02 using The H.A.M.B. mobile app

 

UPDATE... Well we rebuilt both the rear and front spring mounting systems. We even eliminated the spacers that were in the front by going with new brakes and drums. ( near new F-1 brakes drums and hubs will be available in 'parts for sale' soon... )We rebent steering arms to correct Ackerman and the rest of the geometry is now correct. BUT..... as you see in the last photo, this car had truck hubs on car spindles! That bearing is 1/8" too big! I suspect our death wobble was caused by this, but we've got this car straight and secure now. She drive like a windy Cadillac go kart now. A pleasure..... Thanks for all the input, guys. I think we covered all the bases. How come someone didn't say "Make sure the hubs fit the spindles..."

LOL!!!

 

Looks like new springs on the front too. "Make sure your hubs match your spindles!" Lol

 

"more" springs... front and rear