idk why but im thinking throw out or pilot bearings...alternator and water pump bearings,..p/s to if equipped,.....if you dont trust your mechanic you need to find a new one you do trust and pay him to check them wheel bearings again,could be your issue to....only other thing i could think of at 70 mph only might could be the air pressure pushing down on car body causing a tire rub issue but thats pretty far fetched....
