Did you change the aspect ratio of your tires? (or swap out rims?)
Could be bushings.
Could be slight flare in tire well.
Could be lots of tiny little things.
Unless you vehicle is shaking violently, it doesn't sound like a problem to get your panties in a bunch.
Martin '01 Formula - MTI Air Box Lid, K&N Filter, Hurst-6, SLP Cold Air Induction & Smooth Intake Bellow Corsa Catback w/Premium Tips '83 V45 Magna