I acquired a handful of miscellaneous parts from a former stingray collector. Three of the wheels are approximately 18" in diameter and I can read "Schwinn s-5" stamped into one rim so far. After checking Sheldon Brown's charts, I decided they must take 22"tires. The charts also mention "Rare juvenile size...Schwinn". I have no need for them but they have sparked my curiosity. What bicycles were these found on?