crofrog is absolutely correct. It'd take a significant amount of imbalance to get the wheel to move when using its regular bearings.
You can get a decent motorcycle wheel/tire balancing setup for about $35 on amazon. it includes a straight steel rod, 2 conical adapters to make that rod work with most wheel bearing sizes, and 2 "feet" with MUCH freer spinning bearings than what is already on the wheels for that rod to turn in.
I had to cut the small end off one of the cones because our front wheel hub is so narrow the cones were touching before being tight against the bearing.. but otherwise the setup worked great. I could be pretty repeatable with only a 2.5gram change in balancing weight.