what would cause a thumping in both front end tires? on 1998 Ford Explorer

a friend rotated my tires and did not balance them? would that cause the tire to feel like if u had rocks in your tires? i checked for tire pressure to make sure i had proper air pressure. and its good. front end other wise in good shape.

Asked by for the 1998 Ford Explorer
was it this way before you rotated the tires??

no not at all.