DAMAGED RIM, im telling you. I hit the pot hole of doom once and got bulges in two of my tires, got those replaced...still vibration only at highway speeds. Got abent rim replaced(the bends were only visible on balancer and only on the inside of rim, not outside or rim)...and still vibration. Okay went to 3th tire place(1st mazda; they said all good. 2nd local dunlop tire place; they found 1 bent rims. 3rd carx; found 2bent rims!) turns out the set of two bent ones were on front, when got new tires they swaped wheels front to back and only found first bent one that was originally on back, then when i went to the last place they found the other two bent ones. Replaced with msp rims and DA-DA-DA! NO VIBRATION ANY MORE.
thats prolly whats up man, it was frustrating for me so i know what u going through!