If the problem just started after the new tires/wheels I would first look for a missing weight. You should be able to tell where a weight used to be. If not, rotate the front tires to the back and see if the problem follows. If it does, you will now feel a vibration in the body of the vehicle which would point to a bad tire and/or wheel. If rotating the tires makes no difference, then you have something going on with the front end. I have seen tire shops install new tires with impact guns with no regard to torque values. If the wheel is over torqued and/or not torqued evenly, it will distort the brake rotor thus causing the vibration you're describing.