Cupping on steer tires (with pictures)

I'd check the wheel bearings. Cupping is almost always a bad bearing, or a Goodyear. A lot of turning will wear the outside edge too, it GRINDS into the pavement on sharp turns.

 

Yes, it seems to be a common problem. Start there and get a three axle alignment at a good shop,

 

Probably needs shocks all corners. For some reason people think they last a lifetime. Most only last 100k miles, maybe 150k if conditions are excellent.

 

I've never worked for a company that replaced shocks on any truck. Even if they were leaking, spray it down with brake cleaner; DOT will never know.

I've driven 15 year old Cascadia's with over a million miles with the original shocks.

 

I always replaced my steer shocks when I got new steer tires, drive shocks were replaced every year at Christmas break.

 

Never heard that cupping tires aren’t legal on the steer. I suspect google may be wrong unless you find the reg that states it.

 

They are still legal, The Goog is wrong (as best I can tell from your pics anyway)

But, they won't be for long. Once that flat spot gets below 4/32", it's done. And, that's gonna be one vibrating MF'er