An apparatus for mounting and removing tires from wheel rims having at least three arms with means to engage the wheel rim for holding it. Each of the arms has one end pivotally secured to a circular plate and the center portion of each arm is slidably and pivotally mounted to another circular plate so that the free ends of the arms are radially movable when one plate is rotated in relation to the other. Braking means continuously engage one of the plates to insure relative rotation between the plates. The braking means move in a radial direction so that the braking surfaces will be self-cleaning.