A spoked wheel rim for a wheeled vehicle, a mounted assembly incorporating this rim for such a vehicle and a method for assembling this mounted assembly is provided. This rim has two rim edges and a rim bottom covered by an annular ribbon that is flexible and sealed against the inflation gas that is intended to receive a tire and that is fitted with an inflation valve for inflating this tire. The ribbon includes a central portion conforming to the shape of this rim bottom and two lateral portions protruding axially from these rim edges. The lateral portions are capable of having a portion of their axial width cut off by the detachment of two respective peripheral sections of these lateral portions, so that this ribbon extends from one of the said edges to the other following this detachment.