[samprix]

The bad motor mount would probably cause noise and vibration when the engine is under load from the accelerator. Side to side forces (as when turning) tend not effect the bad motor mounts to a degree that would cause noise and vibration because the motor sits in the engine bay transversly in front drive cars. Under load the motor rocks front to back as opposed to side to side in a rear drive car.

The motor mount could still be bad, but my guess is that the wheel bearing will solve the problem you're describing.