I have just under 1k miles on mine and haven't done much interstate driving.Hi,
I just purchased 2018 mazda CX 9 sport and I have been driving it for few days now. I can feel the vibration when I drive over 65 mph speed. I have only driven 200 miles.
When I do take the interstate, at times, I have noticed slight vibration above 65 mph at the onset. It's very slight and seems to fade away in time.
When I feel the vibration, I make a mental note of the speed. Later on, I'll bring it up to that speed to see if it's still there. It fades.
I have Falken tires btw.