tire changer is a device, used in professional workshops and tire
sales and repair shops, to mount or remove tires.
Tire changers come in a variety of types, are usually pneumatically
powered, and will work with most common tire sizes. To remove a
tire, the wheel rim is fixed securely to the tire changer by a mechanical
or air-opeated clamp. High-pressure air is used to draw the bead
of the tire away from the wheel rim. Then a bar is pushed under
the wheel rim and rotated by air pressure to free the tire.