Chasing a death wobble (1 Viewer)

[aktundra]

I’m still chasing a death wobble of sorts.

Not sure the relevant mods. But I’m running 44’s with a modest AT tread mounted on 15x12 wheels. The tires have been trued, and the wheels generally balanced with lead. Front wheels balanced, rears out by an ounce or two, but just cannot be balanced any better. The front end has been rebuilt with new bearings & seal & TRE’s. 2” body lift and 4” Slee springs.

I can cruise 60-70 MPH for hours.

However around town, or slowing down for curves, a wobble starts in the rear, around 40 MPH, and as I continue to slow the wobble increases and moves forward till the wheel begins to shake, and the truck’s almost jumping up & down. Back on the gas, rather than slowing, wobble decreases

Seems to me the issue is in the rear, but reinforces itself, till the whole truck is shaking.

Anything left for me to try ?

 

[voodu3]

Does it happen when you’re accelerating to 40 then go away at 60? Or does it only happen when slowing down?

 

[Rwhat]

Have you tried golf ball instead of wheel weights?

 

[slow95z]

could be in the driveshaft

 

[inkpot]

Check all 18 control arm and panhard bushings for wear,aging,failure. If any of them are getting loose it can allow small amounts of off balance to be magnified into big problems.

 

[Zjohnsonua]

Fought this before. Mine turned out to be a bad tire. The set had balanced fine on static balance but the one bad one was WAY out on the road force machine. You might try moving the tires front to back one by one to see when the issue moves axles?

 

[aktundra]

Check all 18 control arm and panhard bushings for wear,aging,failure. If any of them are getting loose it can allow small amounts of off balance to be magnified into big problems.

We put on Slee’s kit when we put on the 4” springs, I think that covers the bushings

 

[aktundra]

Does it happen when you’re accelerating to 40 then go away at 60? Or does it only happen when slowing down?

I can check if it comes when accelerating through that range, but if it is wobbling not much. When slowing, if I’m in a situation where I’m able to promptly, give it gas, I can stop it from growing to a big problem until moving +40 again

 

[aktundra]

A friend suggested putting the axle on jack stands, and carefully pouring balancing beads down the valve stem, for the rears, that are not balanced to 0, since the wobble seems to start in the rear, and move to the front as it grows.

Except I think you need to be going 30 mph for beads to do their thing.

 

[White Stripe]

What is the general construction of the track bar your using? It may be with all the unsprung weight that you need heim joints. Another thing you could try is some 9000 series rancho shocks. Adjust the settings to firmer and firmer to see if it makes the wobble go away. It may be the big tires are just overpowering the shocks. I would probably try the shocks first.

 

[Corbet]

We put on Slee’s kit when we put on the 4” springs, I think that covers the bushings

I would say no, Slee’s kit does not include new bushings for all suspension components.

And I believe I speak for everyone here when I say please post a picture of the truck on 44’s.

 

[aktundra]

I would say no, Slee’s kit does not include new bushings for all suspension components.

And I believe I speak for everyone here when I say please post a picture of the truck on 44’s.

 

[-Spike-]

Although you rebuilt the front end, check your bearing play by lifting the tire and push/pulling the top. If you feel a clunk, tighten the bearings. Assuming your trunnion bearings are good. Same test works for the rear.

Even with everything tight on my truck, if a front tire is out of balance it will wobble. I've never heard of the rear wobbling, but then I don't talk to many folks on tires larger than 37's. Every inch magnifies potential issues.

I am running 4 ounces of .38 gram airsoft BB's (note they don't seem to offer .38g now, but .36g will work just as well) in my tires, which make up for any imbalance due to wear or wheel slippage after they were balanced. I use this tool to break the bead to put the BB's in. The tires, which were out of balance before, now run smooth at all speeds.

Otherwise, bushings (control arms, panhards), tie rods, steering damper, proper torque on all of the above. You may be a candidate for poly panhard bushings with those huge tires.

 

[shocktower]

I run beads, and how they say they balanced those tires I am amazed on how good they are, I would never use golf balls they are not a consistent, weight and they will bounce, the balance beads are glass beads and don't rust stick or anything else