This is an attempt to explain the methodology used to obtain the motor specifications as listed.
Minimum voltage is the lowest voltage at which the typical motor will start and run unloaded.
Maximum voltage is the highest voltage at which the motor should be run unloaded due to high RPM.  This is a value judgment made by observing the operation of the motor. (sound, vibration, etc.)
Unloaded current and RPM for specified voltages are typical values.
The amount that any motor will vary from the specified values depends a lot on the quality of the motor.  Precision motors may all be within 5% while toy motors may vary in some measurements by over 100%.
Many of the small DC motors are a thing of beauty.  They are amazingly precise, well finished, and will have (when used properly) a running life longer than most of us will care about.
If you have added questions we will try to get answers.  Send your questions an comments to: