Car shutters/shakes while driving faster then fifty km/h

Every time I take my car on to the road and speed up or go a certain speed the car shakes as though it is ready to lose a tire. I have taken it into the shop multiple times and had tires balanced and been told there is nothing wrong (balancing the tires helped slightly) and I have had the drivers side wheel bearing replaced fairly recently. Just wondering if there are any other things I should check for to see if it is the issue for some peace of mind?