2013 X with 11K miles and stock wheels and tires. The truck feels like it has a balance issue - vibration from around 40-50 mph and from 70 on up. But, it is intermittent. The other day, I drove 20 miles or so on the highway in the morning and it rode smooth. 4 hours later, the same drive had enough vibration that the rear view mirror was blurry. It's Florida, so there wasn't much temperature difference in the road. The dealer re balanced the wheels which had no effect - and made sure to warn me that they had no warranty on the tires after 1 year. Unfortunately, this problem seemed to creep up after 1 year and 6 months. I've heard some people complain of the stock tires flat spotting, but it really doesn't seem like that because my other car has z rated tires that flat spot after sitting for a week, but driving for two minutes seems to fix those flat spots. Any ideas as I really don't want to be on the hook for new tires when these have only 11K on them.