Abstract: To compensate for shifts of the mid-circumferential centerline of an expansible carcass relative to the apparatus for expanding the carcass into an inexpansible breaker-belt positioned coaxially and in annularly spaced relation therearound, a reference plane is provided by three circumferentially spaced points directly connected to and equidistantly from the mid-circumferential line of the carcass. The breaker-belt can then be registered in symmetrically centered relation to the carcass by reference to such reference plane despite shifts of such line relative to the apparatus.The foregoing abstract is not to be taken as limiting the invention of this application, and in order to understand the full nature and extent of the technical disclosure of this application, reference must be made to the accompanying drawing and the following detailed description.