What could have caused this.

Cupping that bad means alignment, front end or suspension issues. Take it to a heavy duty truck shop capable of doing alingment work and find the source of you problem.

It wont be too long before you expose the belt and in this hot summer pavement not much to turn them into bombs ready to tear your hood off. And drag you off the road at speed.

 

Shocks, alignment, tie rod ends, kingpins, bent wheel.

 

All of the above.

Those tires are bad. Like to the point that you should've caught the issue a lot sooner.

 

"Brand new"

"90k on them"



What everyone else said. It's cupping, likely a bad alignment. I take it your steering is shaking at 40-50 mph?

 

Mine started doing the same, but only on the extreme outer edges.

Was also told could be spring pads? But not sure if that's true..

Wheel bearings played a part in mine. No shaking at any road speed. No pulling side to side either..

 

What are you talking about? There's nothing wrong with that tire! (Says my former boss)

 

I once went home telling a boss like that call me when that thing is fixed. Or hand me one of them newer petes in the remuda you have in the far corner.

Boss: HAYULNO. And you can imagine the distress he was experiencing with the thought of handing over a 90K tractor to his pets. But not to a ordinary driver in his fleet that does not do badly but nor outstanding either. Just average.

7 months later that company imploded and that was the end of that.