conti extreme contacts here ... no problems ...

how long have you been driving on them ? perhaps having them balanced on a road-force balancer by properly trained tech would solve your out of balance issue as that machine takes into account the balance of the tire and wheel separately and allows the tech to rotate the tire on the wheel until they are as perfectly balanced as possible without the use of weights ... then the final run is for adding weights ... a lazy tech will never do this however as rotation of the tire on the wheel is a physical chore they do not enjoy.

just mentioning in case ... not necessarily cause that is the case.