Not really a good idea to test this on jack stands. Do it on the ground. It is normal for only one wheel to spin on a non-lsd car, but you might actually do damage spinning one at 30mph and letting the other on stand free. If it is the wheel bearing and it causes enough resistance, at 30mph the drive wheel power is going to shift to the wheel that is easier to spin and you could possibly blow a diff pin. So test your ideas on the ground and then come back with more info.