Wheel wobble fixed share my findings. "37" tyres"

So I built a challenge truck back in the summer. I no master fabricator but I've always wanted to try my hand at building a tray back.
So on completion I fitted a set of beadlock wheels with 37" tyres. There started my problems.... Over speeds of 40 mph I would suffer a slight wheel wobble that exploded into what would be described as a tank slapper.... It felt like the steering was going lock to lock.

Now all bushes had been changed when I was doing the conversion so that ruled then out.
So I had to look a bit harder, this was how I fixed it......

Front wheel bearing adjustment to remove a small amount of play.
Adjusted the swivel housing bearing preload.
Installed a terriferma 4 stage steering damper
Tyre pressures checked.

With these mods and adjustments everything runs really smooth.
Hope this helps someone else...

Often peeps 'cure' this with a new steering damper but it doesn't last, but you have found the main culprit in the swivel preload. Search 'death wobble' and you will see how common it is. First time it happened to me I almost soiled the seat but was easy enough to just pull a spacer out.

Yup, steering swivel bearings make a big difference, whatever your tyre size. I renewed mine and it was much steadier and more driveable at motorway speeds.