Ok.... so.. I just bought a 2016 silverado Z71 double cab with the 18" wheels that came with bridgestone dueler tires.
Guess what... I thought I was going crazy feeling this vibration at 40ish mph sometimes lower... and often on highways. Wtf I bought a new truck for a reason! If I wanted to feel a vibration I would have kept my 2012 jeep wrangler with 33" BFG KO2 tires.
I'm at 721 miles and I am cringing at the fact that I need to bring my "NEW" truck to the dealer. Now that I know this is a common issue I'm not happy GM/Chevrolet.
Hope there is a quick fix.