Model A straight axle shake. WHY?

Lots of great suggestions. Problem Solving always goes back to basics. I solved the same problem only I did it backwards. I changed the wheels old junk steel and the tires to new rims and tires. Had them mounted and ballanced on NEW ballancing equipment and the problem went away.

 

So here's what I did.
I borrowed a pair of Weld Wheel skinnies with the same size tire as what I had. I can run the car up on top of the rev limiter in fourth gear, grab fifth and let it eat some more and go over the same road irregularities and not have the jack*** mode.
I had my same front wheels and tires as pictured road force balanced at a chain tire store, they saw and felt no visible irregularities in balancing procedure. Put them on the car, the front end feels more smooth than newer tires.
So for me to draw a conclusion, I feel like the tires being out of balance, combined with front tire pressure being low, made the front of the car act like a jack***.
FWIW, do the math on 5000 rpm, direct fourth gear, 4.10 gear ratio, 29" tall tire. No jack*** mode. Then grab an overdrive gear. Sound good too, three deuces open makin' the pipes holler..................

 

10-4 added a panhard bar to my coupe different car

 

refer to threads putting beads in tires??????????

 

my dad's model a had a weird shake on drivers side , turned out to be a hairline crack were the pin is pressed in to hold spindle . it only shook at certain speeds .new axle cured it.

 

I agree with "thepolecat" if you dont have a panhard bar get one. I had the same problem on my 29 roadster. I had steel wheels and bias ply tires. I had the tires balanced at two different places with little or no change. I purchased four new American Mags and mounted Michelin radials from Diamond Back on them. I found a tire company that specialized in high performance wheels and tires (Porsche etc.) to mount and balance the tires. Fantastic improvement but still a little off. I read an article by Posie in it he recomended lowering the tire pressure for light weight cars.
I dropped the tire pressure to 24# in the front and it drives like a new car.

 

A little bit of back from dying or dead.
Radial tires that have pretty and deep tread that are 6 years old are like a $100 saddle on a $10 dollar horse. Just because it looks good doesn't make it good.
Pretty tires will separate with time and 0000 miles. It doesn't matter how much you paid for that tire.
Can't change it or ***** about it. Take it to the bank or withdraw $$$ to get over it.

 

Check that the front spring is not too short, as too much angle on the shackles. It lets the shackels reverse, one pointed down, one pointed up, then reverses.

 

Here it is!! If you want your car fixed, toe it out to almost nothing!! I had this problem 25 times or so over the years. All new parts,I mean everything and it still shook, toe it out and it will stop (if) everything is good and tight. Also like one guy said a panhard bar will help some but dont have to have it, I dont on mine. I will help with the rock back and forth in the shackles, Just toe it out and you will be sooooo happy!!

 

With that said, does toe in or slightly out have a different effect with bias vs radial ply tires? I have radial tires.

 

warpspeed-I have an I beam front end, stock axle/spindles and spring with 4 leaves removed. It goes down the road 75-80 mph straight as an arrow. Needless to say, you have to keep on top of kingpins,rod ends. I believe the factory manual wants them greased every 500 mi.

 

Shook out of why how the problem was caused based on new front tires cured the DEATH WOBBLE.
Anybody remember the lesson of the date code of tires? Tread depth doesn't matter.
Ever had your front tires to cause your radiator to wave at you at 80 mph? It's fairly to major unsettling when you're at the wheel.
I read the lesson and challenged it. I didn't have a wreck to kill my car or me.
Keep track of tire production date codes. Don't ***ume a tire with good tread is a good tire.
Is there a problem with OLD slicks having been brought back to life?