Humm, where to start. First off you have whats called and static and a dynamic balance. Dynamic is the best. With dynamic there will be weights on the inside of the rim as well as stick on in the middle, or some shops put weights on the outside. If you have a static balance the rim is only balanced in one plane. Get a dynamic balance and that should fix it. If that does not work there is one more option. Your hubs, rotors, cv's or any other parts may be out of tolerance. I have what is known as a dynamic on-car balance done to my car. An on car balance means they balance the rims on the car. This is the best balance. There are two downsides. One the tires have to be balance every time they are rotated and two it cost about 40 dollars for all four tires. The car is much smoother afterwards though and there are actual performance gains associated with an on car balance. I hope that helps you without going any more in depth.