Hello all, I joined the forum because I was having major death wobble issues and was looking for advice. I have a 1930 model A coupe that was custom built in 2013. It uses a bell 48” straight axle kit from speedway with ford style spindles and disk brake kit also from speedway. Utilizing leaf spring, and fords version of the houdaille shocks for suspension. The car is a great cruiser. Several 1 to 1 1/2 hour drives with not as much as a shimmy in the front end over bumps. About a month ago I found that my spring perch bolt was sheared and needed replacing. I decided to take the entire front suspension off and repaint parts while I was there. I replaced the newly painted front end and took the car for a test drive. Upon reaching approx. 40mph and hitting a bump in the road, I experienced my first death wobble. I don’t wish that on anyone!! Definitely a “pucker factor” moment. Got the car home and started trying to figure it out. Troubleshooting was extensive and involved doing multiple searches online for death wobble remedies. There are several trains of thought on the subject, but one consistency throughout my search was that almost everyone recommend checking alignment. “More toe in!!” if there is wobble seemed to be the consensus. So after starting around 1/8” in, I began giving it more toe in until I reached nearly 3/8” before realizing it was only getting worse… a lot worse. Because I am a rookie mechanic, I figured it must have been something I put back together wrong and decided to tear down again and put back with more of a “pay attention to detail” at***ude. And after the second re-build and a 1/8” toe in I started out on my test drive. Same results. After more research, I came across some info detailing tire wear for various alignment problems. Came to realize my tire wear was consistent with toe out wear. When I say tire wear, I don’t mean excessive…there was a slight feathering to the tread which indicated (according to the site) an outward toe. Sure enough…I set the toe at 1/4” out and, lo and behold, the death wobble went away and the car tracked and drove just as solid as it did before the repair. I am still going to adjust the best I can so I don’t have excessive toe for no reason but toe “out” is definitely my cars happy spot. My question is…is toe out always wrong? If I have to toe out, is that because there is another problem that causes me to have to toe out? Or is that just what works for my car? It does have an extreme caster of 10*. Like I said, it tracks perfectly down the freeway at 70-75mph and steers/handles just fine. If all I have to worry about is feathering of tread after 4-5000 miles…is that such a concern? Thank you for tue help.
Once the tires wear in a pattern it pretty much stays that way . Toe out causes the vehicle to wonder around when driving. Toe in will tend to make it drive and track straight . Death wobble is usually a sign of some other problems. Tommy
Jack up one front tire only and try to move it back and forth against the steering linkage as if you were toeing it in and out. If there is any slop in the steering linkage, you will see it here. A helper will let you look while he manipulates the wheel back and forth. Fix any sloppy issues you find and then try it again. There could still be other problems but this will help you make sure you have put it back together as tight as possible.
Google gyroscopic precession to get a basic understanding of what it is. Usually there's some looseness in the front suspension somewhere that causes the onset of the death wobble. Check the wheel bearing settings, the kingpins for play, the tie rod ends for some slop, the drag link as well, and even the steering box for play. Having toe out that "cures" the death wobble points to something connected to the axle. Toe out puts the tie rod in compression, preloading the tie rod, kingpins, and bearings. Not so much the drag link or the steering box. Hope this helps you. Good luck!
It has a lot to do with good king inclination. The idea is zero toe going down the road. The angle through the king pin should be in the middle of where the tire where it meets the road. If it is to the inside the toe will tend to move out driving if outside the toe will tend to move in. So you can guess what happens with reversed wheels.
Most likely, the toe out is helping to mask a loose/worn component or incorrect suspension design. First, do exactly as Rockable says, then if that doesn't lead you to the worn component, post a pic of your set up. Not a super close up, just a good shot of the whole deal, we might be able to spot something. We talk about death wobble on here a lot and we can always figure out a way to fix it. -Abone.
How about some nice clear pictures from the front and above. We may notice something you are not mentioning or seeing.
To much positive caster will cause that... Run 3 degrees positive and an 1/8 inch toe end and don't have any issue's....
The basis of using toe in is to make it easy ( along with caster and camber ) to hold the car in a straight line. Any experience with a yard tractor will tell you how toe out makes frequent turning on rough surface easier. The 'feathering' on you tires may just as well be from excessive camber. Combine too much camber with toe in, and the tires are in effect tripping over themselves. I found no mention of camber in your post. If nothing else I would try swapping left to right. Check the camber, reduce the caster, then play with toe settings.
Here's a great discussion on death wobble and toe-out. Technical - Need help/suggestions - '34 Ford front end trouble | The H.A.M.B. (jalopyjournal.com) Having a LOT of experience with death wobble on my old Sedan Deliv., I recommend every Ford spring-over straight axle should have Adjustable spring perches, panhard bar and a steering damper.
1/8 in toe in, 3 to 6 degrees of caster, change kingpins and their bushings, rod ends on tierod and drag link,, adjust the play out of your steering box, dynamic ballance the wheel and tire ***ys front and rear then you should be good. Toeout is only on Front Wheel Drive Cars.
Toe in is for rear wheel drive cars. Toe out is for front wheel drive cars. If you have to resort to toe out, you have another problem, wear or looseness somewhere in the steering/ front suspension system .
In 40+ years of doing alignments and frame never once have I ever ran toe out on a front wheel drive vehicle including my own. My record is 70,000 on 1 set of tires on a grand prix and no toe out.
FWD cars try to toe in when they first start to move so a little toe out helps them go straight instead of toeing in when they take off. If everything's new toeout is not needed. Ive owned 3 Toronados and 2 Cords with an 1/8 in toeout. Really no big thing we're talking about 1/8 which is tiny.
Some general spec's here from the Model A restorers: https://www.mafca.com/downloads/Technical/Front End Seminar Notes Hershey 2014.pdf
Toe in or toe out it doesn't matter, both will cause your car to wonder/ Toe out with a degree of negative camber will have your car taking bends with the best of them. Toe in kind of gives it a tight feeling. Most people think its what they need with power steering thats over ***isted. A power steering box by a company like Lee with a 30 pound torsion bar will get you what you want. You'll have a real strong snap back to center after turning. Its not in the caster, or the toe its in the steering box.
It’s interesting if you Google the subject. Until this thread, I never would have thought about Toe Out for a street driven vehicle.
Thank you to all for the replies. I must preface my response by saying that my experience with mechanics is very limited. So excuse my ignorance on some of what you guys are saying. As far as camber and caster goes…they are both fixed as far as I can see. Camber is built into the straight axle and spindles right? Unless the axle was heated and bent I don’t see how it can be adjusted. Caster also is not adjustable from what I can see. It is a solid radius arm with caster built in and mounted to the frame at the angle the builder put in. The only “play” in the steering is a very slight “flex” in the mounting for the steering box. But that was not disturbed by me during the repair so I ***ume it’s always been there and, since the car drove great before the repair, I don’t see how that contributed to the wobble after the repair. All other points along the way between the steering box and wheels are solid as can be. As far as binding goes, I have lifted the axle one side at a time maybe upwards of 6” up and don’t notice any binding…is there another way to check for it? I am confident the car is now back in the same condition it was before the repair. Tracking great with no wobble. So I guess the new question is…is what caused the perch bolt to shear related to the need for toe out?? Or could toe out be part of the builders design to go along with caster, camber, and whatever other variables go into building a car /frame from the ground up. Thank you again, your advise/info is greatly appreciated…and have a great Christmas!!
You might read @Pete Eastwood comments on correctly utilizing cowl steering, here: https://www.jalopyjournal.com/forum/threads/cowl-steering-just-stop.1101046/ Photo from above post: https://www.jalopyjournal.com/forum/attachments/7feae277-4b21-435e-be43-2c671cbfc619-jpeg.5602139/
Front suspensions where the steering arms are forward of the front axle seem to be particularly susceptible to Death Wobble. I suspect the hemi joints on your steering link. They look like the elcheapo rods from Speedway that even when new always seem to have a little bit of play. Fit the steering box mount then try the wiggle test again, I bet you find something. -Abone.
Not much help, but : my stock suspension ‘32 fordor has 10* and drives okay. I have heard figures of 3* to 10* on this forum with no issues. I set my coupe up at 7* because that seemed to be the definitive way.
Thread discussing front steer tie rod and Ackerman principal: https://www.jalopyjournal.com/forum/threads/help-forward-steering-ackerman-issue.1281592/
Joe, don't sweat it anymore, enjoy it and drive it. I've been there with the same issues 30-40 years ago, and Toe-Out stopped my issues and my Coupe drove excellent, fact is I drove it 54,000 miles ... no issues. I too use Heim ends. A very good friend of mine who built dragsters and funny car ch***is (R.I.P.) for 40+ years told me that toe-out will stabilize the front end and make it so you can drive 200+ mph. I'm not cramming this down anyone throat, sometimes folks need to talk and listen to the old guys that really were there and did it until they figured it out. God Bless and Merry Christmas!
Camber can be changed, it's set by bending the axle cold. Installed and ready to drive condition that way any load subjective to the axle is already there. We still have the special tooling at work, actually have the tooling to bend caster too in a situation like yours were the axle is mounted in solid configuration. I've probably bent camber in over 500 cars in my life and around 100 for caster. I haven't bent caster in one in about 10 yrs due to the fact many use some kind of adjustable arms now. Bent one for camber just a couple months back. You can ONLY bend forged axles not cast, cast will break. It's old technology nothing new. Although it's still used today in tractor trailer rigs. Bend those about 4 or 5 times a month. It takes 2 separate 110 ton rams to do those. This again is old tech, the straight axle, the camber and caster bending it's just not too many old timers or tooling still around that have the experience to do it much less remember it. It's an almost dead art. Maybe I should write a book..... .
It's feeling like the toe out was done to mask other problems, so the rod could be driven somewhat comfortably. The list of areas that need attention: Incorrect cowl steering arm geometry, creating bump steer. Heim joints rather than time rod ends on the tie rod, likely adding loose steering feel. Lack of Ackerman, steering arm angle, creating tire scrub when turning. Owner's comment about steering box mount. OP will be sorry he started this discussion, but in addition to death wobble is vehicle safety.
When I get a leading link front suspension vehicle in the shop, when all other components have been ruled out, and it still exhibits death wobble, running 1/16" to 1/8" of toe-OUT usually fixes it.
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