made by bonding or by inserting the strip in the sole during the moulding of the support ring fig4 illustrates a foam support ring 4 according to the invention in which the strips have been positioned circumferentially on the sole and spaced apart by a given circumferential spacing u201c p u201d this spacing is determined according to the number of strips that have to be positioned in order to obtain the desired mechanical strength while at the same time maintaining the circumferential elasticity of the support ring in order to allow for fitting in practice a spacing substantially equal to the width of the strip allows the desired compromise to be reached fig5 to 9 illustrate two particularly advantageous embodiments of the strips specifically it may prove necessary for the system formed by the tire and the foam support ring to be disassembled for example when the foam support ring needs to be replaced after prolonged use in deflated mode still according to the invention it is proposed for the spring leaves 51 52 to be equipped with an extension 53 54 extending each of the leaves 51 52 in a direction directed substantially radially outwards and placed in this direction above radially outwardly of the protrusion 301 302 the shape of the extension 53 54 is designed to fit around the protrusion 301 302 and thus making the spring leaf accessible to be disengaged from the protrusion as a preference the extensions 53 54 have the overall shape of an s the lower part of the s situated radially towards the inside fits around the protrusion and the outer part of the s situated radially towards.