Task: Translation
Input (Spanish): The method comprising: providing the radially inner portion (11) in the form of an inner tube (21) and assembling the radially outer portion (13) about the inner tube (21).
Output (English): El método comprende: proporcionar la porción radialmente interna (11) en la forma de un tubo interno (21) y montar la porción radialmente externa (13) alrededor del tubo interno (21).