Straight axle shimmy starting at 62 MPH

I'm ready to give up. I've got a 33 lowboy with a Pete and Jakes straight axle, Unisteer, ET 3 wheels, and radials. I can't get rid of a shimmy that starts around 62 MPH. I've replaced the front shocks, king pins are good, it's been alighned with a 1/8 toe in. I just tried ceramic beads in the tires, and it didn't help. Any ideas?

 

Do a search for steering dampener. It might help, so-cal sells them for reasonable.

 

Try adding more caster.

 

Pics please of all of the front end components.

 

That speed is usually a tire balance issue. Also look for excessive wheel runout.

 

I agree..

 

broken belt in the tire caused my buddies shimmy. took a while to find it, jacking the rig up and checking k/p's, tie-rods and what not. only found it after swapping tires around.

 

+1 for more caster... then steering dampener.

 

That's the ticket!

 

Twisted belt, probably in the right front tire, from hitting curbs parking. Not usually visible, try a different set of wheels and tires to find it.

 

Speed related shimmy is almost always wheel balance. Does the shimmy go away at higher speed.Is it not there at low speeds or just not as bad.If it starts at a certain speed and then goes away at a higher speed it is wheel balance.

 

Try putting more air in the tires and see if it makes a difference.....

 

Death wobble or speed wobble search

 

have you tried switching right wheel and tire for left to see what happens?

have you tried a different set of wheels and tires, (even if they are not pretty, just to prove that its not the tires or wheels)

 

Lots of threads on the dreaded "death wobble". In most cases, it proved to be a tire/wheel issue, after the member had gone round and round, changing this and that. If a suspension and roling-stock is in good shape, and engineered and assembled correctly, there will be no need for a steering-stabilizer...that's a bandaid-fix. And more caster isn't going to smooth out something that's out of balance. Good luck.

 

Do you have discs or drums up front? Had a similar problem. I tried everything and then someone told me to look at the brake drums. They were unbalanced. Changed them and it worked.

 

every time I've had this problem it's been solved with good tires - if you need to hear it again.

 

Thanks for the advice, I going to have to systematically go through everything.

 

I agree with wheel balance as long as the front end was set up properly to begin with

 

You will feel a separated belt at all speeds. The tire is actually out of round and you feel it every rotation of the tire no matter how fast it is revolving.

A shimmy that occurs at a certain speed it's due to the RPM of the tire at that speed. It's almost always a balance problem.

The man that I worked for had a permanent plastic sign made for the front counter..."A front end alignment will not correct a shimmy."

 

x2 on the drum issue. I fought with the same kinda deal for a couple years before stumbling onto an out of balance drum.

 

have the front tires speed balanced on the car that way every thing is balanced together. just make sure they go back on the same way if you ever take them off.

 

Lots of idea already. What are you using for brakes? The Raven had a weight missing off of one of his drums. Probably not the problem but a few years ago one of the fellas had a death wobble issue and we discovered he had a broken leaf.

Just a couple of things to help muddy up the waters.

 

Try swapping out a different set of front tires and rims. Chased a problem like this on my father in laws pick up and it turned out to be a tire with a belt gone wonky.

 

All good suggestions, so the key (duh) is to start with the obvious before moving on to the deeper stuff. Alignment, balance, and a good check for broken/worn parts would be the place to start.

We had the same issue on Joyce's pickup - just a little side-to-side wobble between 60-65, but like butter otherwise. After alignment, balance, and new tires didn't do it, I dialed in a little more caster and it was gone.

 

I'd have to go along with the out of balance drum theory too. I've seen a lot of cars that had drums that were out of balance and one aftermarket drum that was so far out it was total junk.

See if you can find a shop that has an on the car spin balancer that spins the front tires with a drum that spins against the tread of the tire. Some of the shops may still have the old Hunter sitting in the corner but if you can find one with a strobe balancer you have hit the jackpot.

Have them spin the front tires on the car and see what happens.

I've seen a lot of drums that were out of balance over the years and one aftermarket drum that was so far out that it was junk right out of the box.

I've also seen hubcaps (especially on early 70's Fords) that were out of balance.

 

7* caster /steering dampner

 

hey spiker, when you nail it down..let us know what you find to be the problem

 

My '34 shimmy-ed at 60 mph just before the bushings wore out in the same type front end you got. They were the plastic type not rubber. DROVE ME NUTS !! New bushings, problem gone !

 

I have early ford drums on my T. I set them up on a balancer without the wheels. and even tho they had the ford weights on them, each was out. one needed .5 oz the other .25oz. I added a screw with a little piece of lead. drilled and tapped a hole in the drum.

It did help a little.