I noticed that my tires on my '97 E350 Quigley SMB were cupping pretty bad on the front in Nov, and I had a long drive to do, so I swapped them all out. Had Cooper Discovery A/T, and replaced with Cooper STT Pro. I didn't notice any vibration from the tires. The tires were 5+yrs old too, so were on the list to get changed sometime soon anyway. My reading on the subject showed the need of getting more tire rotations and balancing.
I have Cooper AT3 and they cup on the outside edge. I was told by one shop that it was the design in the tire. I'll try a different tire when it comes time and hope it is just the tire.
2005 E350 Chateau - V10 - Agile Offroad 4x4
2012 CTS-V Wagon - For the baby...