Wheels out of balance have no consistency as far as what speed the steering wheel starts to shake or if/when it goes away. Doesn't mean wheel(s) out of balance is not the problem.

As far a wheel out of balance I would describe that as the steering wheel shaking side to side rather than a vibration on the floor. I assume they balanced the wheels when you replaced the tires. If the vibration started when you replaced the tires I would have the wheels road force balanced to see if that helps.

__________________
X5 4.6 2002 Black Sap, Black interior. 2013 X5M Melbourne Red, Bamboo interior
Dallas