Method of, and apparatus for, fitting a resilient ring substantially circular in shape into a tire, and removing it therefrom, the method comprising the following steps in sequence: initial deforming of the resilient ring by slightly stretching it along one diameter thereof so as to cause it to change from a circular to an elliptical shape; fitting of the thus deformed ring lengthwise into the light of a tire in which the ring is to be assembled; first releasing of the ring whereby it tends to regain its initial circular shape while remaining engaged in the tire light; final deforming of the resilient ring by stretching it in a radial direction within the tire, and final releasing of the deformable ring whereby it regains its initial circular shape within the tire.