KSCAgent99

We have a 2015 Silverado diesel dually 4x4. We had (6) 285/75R17’s put on the truck. On the rear we added 2” adapter/spacers so the tires wouldn’t rub. On the same day we had a 2” leveling kit added to the front. Tires are BF Goodrich. Ever since, we've had a lot of shake in the tires. Had an alignment done, changed pitman arm and idler arm, wheels rebalanced (off the truck balance), and we still have some shake that changes intensity at different speeds. Trying to decide if it’s the tires, the spacers, or some unknown issue. This is my daily driver (my husband drives the old Ford :-)) and I want my smooth ride back. The shake definitely feels like it’s in the back. Anyone have a suggestion?? Can’t seem to find a shop local that can help. The place we got the tires went out of business.