The S-6 rim was used on the pre-war New World and could be used on the Superior. It had a Stamping mark Schwinn Superior on the rim and was chromeplated steel. Right after the war this was change and it was marked Schwinn Stainless S-6. At some later date this was changed to the Schwinn tubular marking. This bike could have been originaly made for on S-6 rim and it was changed over time to a newer rim if the old rim was damaged.