Was visiting my daughter today and my son-in-law noticed some tire wear on the rear passenger side dually set. I am getting some significant cupping on the inside of the outside tire and the outside ...
This is just a "shot in the dark" thought - did you rotate tires front to rear or did you do a criss-cross rotation? I'm wondering if you are having some cord separation that might have been caused by moving the tires left to right. Just a thought. I'm old school and always keep the left tires on the left and the right tires on the right.