I have a 2014 Silverado LTZ with 20" Continental tires that I picked up in the middle of November 2014. After a day or so I noticed the vibration after 65 MPH and thought the tires needed re-balancing, I figured I'd mention it at first oil change. mine wasn't as bad as the one's I've seen on the you tube video's but there was a distinct vibration. I now have about 3,700 miles on the truck, and the vibration is just about gone... It seems the more i drove the truck in 4WD or auto 4W the better it got. (We got a lot of snow here in New England.) I just got back from a 200 mile road trip and my passengers were saying .. wow!! this truck rides so smooth. At first I was real disappointed with this truck and thought I was going to have to fight with the dealer to correct it. Now I don't think I'm even going to mention it... My truck runs perfect and I'm happy with it.. Just throwing this out there..