New member of the "death wobble" club

[Track T-4]

I took the front end apart to get the axle and spindles powder coated. The car drove fine before but after reassembly goes into the death wobble at various times. Grrrrr. The right front tire/wheel starts a slight wiggle and I know it's coming then all hell breaks loose. A pretty disconcerting experience. With a quick touch of the brake, it goes away. Seems it can be expected especially on a right curve. I know there have been several cases of others on this forum going through the same problem so I'll review all of those comments. The car is running radial tires. Hope to get on an alignment machine tomorrow. Seems to me there is a basic recommendation to shoot for 1/8" toe-in and 5-7 degrees caster...sound right?

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[sstock]

I'm running 1/16" toe out on my Mickey Thompson Sportsman radials, and it definitely drove better than the slight toe in I had it set at.

 

[RPM]

Yep some of these cars like toe out, mine does also. Try some toe out, you might like it.

 

[lincolnuT]

We had a car at the Nationals in Tenn. that had that same problem and 1/16 th toe out solved the problem. Many straight axle cars like toe out........both of mine are toed out.......

Mike

 

[409T]

The geometry of toe-in creates a potential for wobble. The geometry of toe-out does not. I read the whole pile of math that supports this a long time ago, but today all I remember is what I just wrote.

 

[EX JUNK]

409T, did what you read also pertain to a cross steer setup? I ask this because I've never had a problem with my Vega cross steer and a toe in set up. Perhaps the Ford side steer set up is more inclined to this problem. I don't know, just asking.

Jim

 

[donsrods]

The big question is, what changed from the time it drove well to make it not drive well. When you disassembled it did you keep all of the settings the same ? Just taking apart a front end and putting it back together shouldn't create a problem, unless you changed the toe in, caster, wheel bearing tightness, etc. You changed something in there, you just have to find out what it was.

Did you put the tires back on the same side they were on originally ?

Don

 

[409T]

409T, did what you read also pertain to a cross steer setup? I ask this because I've never had a problem with my Vega cross steer and a toe in set up. Perhaps the Ford side steer set up is more inclined to this problem. I don't know, just asking.

Jim

If I remember correctly it only had to do with the angular relationship between the two front tires and how that changed as the car turned through different radius circles. It had nothing to do with types of steering setups or linkage.

 

[railroad]

Check your wheel bearing first. Applying the brakes does a lot of things, but wheels get the first affects.

 

[roadmonster]

If you have disc brakes it sounds like the pad is not retracting.

 

[RESINATOR]

We have found that if your tie rod is out in front..start with 1/8" toe in...if the tie rod is behind the axle, start with 1/8" toe out.
This is just a starting point, drive and test..adjust and keep trying.

Most times this wobble at specific speeds indicates there is something out of wack dimensionally or something is in a bind.

If you haven't changed anything this should be fixable with the toe adjustment. Sometimes just changing tires requires a different setting.

 

[Ted Brown]

THEY Say that the best result to be shooting for is, when driving normal down the road, there is now no tow to either direction, a straight wheel, no tow in or out... The rolling resistance of the tires should make the change from tow in or tow out, and end up to be square... A front mounted tie rod will get shorter when flexed, never longer, so the tow will not change to less when tire resistance tries to make that change... But a rear mounted tie rod will flex or bow a bit and take away that small amount of tow in, back to zero... So I have been told by some older than me... I like Jerry, drive and test, set till all is working as needed, each car/chassis is different... I hate the death wobble...

 

[Track T-4]

Helpful suggestions to check so far. My T has a tube axle, tie-rod is behind the axle and has drum brakes. I slightly increased the toe-in one time yesterday and it seemed that might have helped but found myself a little reluctant to really push it after a couple of wild wobbles the day before. This morning I used an inclinometer (sp?) and the caster appears to be about 5 degrees although the measurement process is a bit rough. I never changed the settings on the radius rods so don't think caster is the problem. I did install new rod ends on the tie-rod so that's probably what I'm dealing with. Local alignment shops are reluctant to do the car because of the lowness and possibility of damaging the wheels so it looks like I need to solve this one myself. Last night someone suggested a steering damper so I'm reading previous posts on this forum to see opinions of others. I'm using the string process to read the toe-in so it's a rough measurement but when the rain stops this weekend I'll try tweaking different toe-in/toe-out increments and see what happens. Will also check the tightness on the wheel bearings as suggested above. The one thing I would like to understand is why the right front wheel starts wobbling before the whole thing goes nuts, never the left. It gives me a little early warning but not much. I had that wheel/tire balanced and checked for straightness while the axle was apart so pretty sure that not the cause. Thanks for all your suggestions.

Ted - I share your hate for the death wobble.

 

[2old2fast]

The likely reason 1 whl. reacts 1st is due to uneven chassis loading , it's just "steering" more w/ 1 wheel than the other. Plal w/ the toe settings , you'll get it .
dave

 

[lincolnuT]

Track-T your wheel bearings can be a lot tighter on a light T than on a full size car so I always go a little past what I would set my other cars wheel bearings. Remember you only weigh about half what a normal car does on the front end so the bearings will work being tighter and that will help NOT start the wobble. I use a tape measure and just do the inside of the tires front & back for my toe end. You will have better luck if you can get on a back road and drive straight for a bit and check the toe. Then drive it again until you can go right up to speed with no problem. I understand what you are going through BTDT......With past experance I would start toe out 1/4 inch.........If that works then watch the tires for wear for a few miles and you can always go back.......

Mike

 

[tfeverfred]

1/16" toe in on mine. You'd think that putting everything back the way it came off, nothing would go out of whack. That's not always the case. I learned from experience to just recheck everything, when I go playing with my front end. Hope you get it figured out.

 

[Track T-4]

To check the amount of toe-in/toe-out I followed a process showed to me using a string. It will be tough to describe in 30 words or less but here goes. You run the string from in front of the left front tire, around the left rear tire and the back of the car, around the right rear tire, and past the right front tire. Now anchor the two ends in the front of the car and adjust so the string is parallel to both rear tires. Now steer the front tires until the distance from the outside front edge of both wheels to the string is equal. Measure the distance to the strings from the rear outside edge of each wheel and that is the amount of toe-in or toe-out. Make sense? Sound reasonable?

 

[tfeverfred]

You know, there's all kinds of ways to do stuff, but I always do what works for me. May not be the right way, but the results are usually good.

Here ya go.... Freds way:

I get the tires pointed straight ahead. I get a tape measure (one that has a tab on the end). I put the tab in the middle of the front tread and measure to the front tread on the opposite tire. Then, I do the same on the back of the tire. I compare the differences. If I need to adjust I raise the front enough to adjust the tie rod. Lower and repeat measuring. When I get it like I want it, I tighten everything up.

Is this the fancy way? Hell no. Not by a long shot. But it's worked for me. I'll wait for the laughs to follow.

 

[2old2fast]

I would think the only way that would work is if your track width-frt. to rear was equal , the way I've done it in the past is to put a piece of tape in the approximate tread center on both frt. tires , roughly 90* to vertical , measure from a point that you can repeat , roll the car so your marks are 180* from where you started & measure the same points , compare frt to rear , that's your toe -in/ out...
dave

Fred beat me to it..

 

[roadmonster]

Read my posts about the simple alignment jig. You will never go back to tape and string! I still think it's likely to be brake-related if you left everything else alone. A shoe that does not retract properly can definitely induce wobble and the fact that it starts with one wheel says "brakes" all over. It does not sound like a toe-in/out problem at all.