I have an 86 F250, 4”Lift, 39” tires that suffered from the famed Death Wobble, as I now know it has come to be known. I unsuccessfully tried everything to get rid of it until finally I’d had enough and swapped out the entire 250 Twin Traction Beam front end for a Dana 60 solid axle. For a while I was convinced that the problem was fixed until a few weeks go when it returned. I’ve read all the posts about wheel bearings, tie rods, spindles, etc. and it all seems fine on my truck. I don’t think that’s the problem because as I said before, it’s the same wobble I had with the TTB suspension, although less of a lateral feel in the steering wheel (the IFS steering system was mediocre at best). Now it is more of an up/down/forward/backward kind of wobble of the left front after hitting a bump. Slowing down is the only thing that stops it. When shaken on the lift, the tie-rods and wheel bearings offer no play. I’m also running brand new Rancho dual stabilizers. The only common links between the two suspensions are the single Skyjacker shocks and the unbalanced 39” bias ply Mickey Thompson tires. Is it possible that it could be the tires causing this entire thing? Would a set of balanced radials of the same dimension offer an improvement? Could the single nitro shocks not be strong enough to plant the tire back down when it bounces? I’m thinking about putting the stock wheels back on to see if it goes away. Sorry about all the questions, if anyone has any advice to straighten this truck out, I would appreciate it.

Thanks again.

Dave
lxturbo302(No Email Addresses In Posts!)

 

Try testing the shocks rebounding. Jump up and down on the suspension and see how many times it comes up and back down when u stop at each corner. It should only go up and back down again and settle out. For 39" tires, 1 shock is pretty light, that could be your problem. Also, your unbalanced tires could also be causing the problem in conjunction with the shocks.


Primary rig is:
95' F-150 EB 300/6 5 spd with 4" Superlift, MSD, Ram Air, Gibson Exhaust, 32" BFG Muds
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Then theres:
88' F-250 Superduty 351 + c6
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The newest addition to the Ford family is a 99' Mustang GT 4.6L

 

Hey Dave, the tires might be your problem. Which M/Ts do you have? You might check them to see if they are out-of-round, and if they are not balanced, they can start a harmonic vibration that can be pretty severe. I don't have the death wobble, but after I balanced mine, it made a huge difference.

I used internal balance pads so that the tire itself is balanced. Myers Tire Supply sells special balancing pads made by Patch Rubber Company. That's the only source I've found. You'll want to find a place that has a Hunter GSP9700 balancing machine and then try to talk the people into balancing your tires.

The whole process was time consuming and wasn't cheap, but I thought it was worth it. If you decide to try balancing and want more details let me know. Good luck.

 

LW555

Thanks for the info. I checked the tires last night and the tires seem to be cupped pretty bad. I can feel a big difference in tread height both across the width and around the circumference. It feels like that could be the problem in itself. I'm not going to bother with balancing those tires because they are shot anyway. I can get a good deal on BFG 35/12.50's which are a little smaller but shouldn't look too bad. I've heard good things about BFG's and I would actually like to try a street radial on the truck to see if the drivability gets better. The up/down shock test showed no problems. If I pick up the BFG's, the truck will get an alignment and they will be balanced. Until then, I may put the stock wheels on and see if the problem goes away. Can anyone recommend a good multiple shock setup for the truck?
Thanks.

Dave

 

Did I understand you post correctly that your tires are not balanced??
Well there could be a mager problem all tires should be balanced and rebalanced every once in a while.
Also if you are still useing the radius arms from the TTB they could be worn out they may look just fine from the outside but on the inside they can be egg shaped and give you some wobble. But I would definitly get the tires balanced and see what happens from there

 

Yeah the tires are not balanced. I mounted them myself and couldn't find a shop that could handle them. I test drove it up to 85 mph and had no vibration so I let it go. To this day, there's still no speed related vibration to the truck. I didn't figure that the unbalance would only cause this bump related problem and no at-speed symptoms, but I think you're right.

As to the Radius Arms. All the IFS equipment is gone off the truck. It's a leaf spring straight axle 350 setup now. It never had coils or arms.

 

death wobble sucks, I have had it before with my 78 bronco.

you mounted the tires yourself, you should have used the powder to balance them.

I know 4wheel parts sells the stuff. you basically throw this thing of powder in the tire, use special valve stems, and when you start driving they are self balancing. never needing balancing again.

 

As to the death wobble with the ttb, my buddy had this problem and we found it to be lose axle pivot bolts. The bolts were tight until you took the weight of the front end of the truck allowing the axles to droop. So anyone with ttb that might have this problem try jacking up the front of the truck by the frame, and tightening the axle pivots. Good luck

Ryan