Keep in mind that Schwinn sold aftermarket repair parts. A 20x2.125 Schwinn BSW Knobby was sold for many years as a replacement part at any Schwinn dealership. I have a 20x2.125 WSW Schwinn Knobby on the front wheel of my Cycle Truck. I don't see this as a Holy Grail part. If your only buying because of the product date code that's a different issue and that's fine.
Goodyear, B.F. Goodrich, Uniroyal, and Carlisle all made rubber products for Schwinn over different periods. One by one, they all stopped manufacturing any bicycle rubber. The Sting Ray sales were so popular I think Schwinn would take anything from any vendor that could manufacture to get more units produced. Persons seats were hard to get initially. Having enough Schwinn tire molds was the problem, since we were selling a large volume of a tire size that traditionally did not sell that well in the past. In general, all of the U.S. rubber vendors had serious quality issues. The same short supply thing happened when the 20" slick's came out, and again when Carlisle and Goodyear began making their 20" motocross tires.
As a sales representative, I was the guy that went through the dealers return boxes each month and wrote credits for any warranty parts. Many inner tubes were replaced before the new bicycles even hit the dealership showrooms. Valve stem vulcanizing was a huge issue for all the U. S. rubber manufacturers. It was not until the early 1980's that more Schwinn rubber started to come from Off Shore and the rubber quality was much improved. We all like to think that U.S. production is better, but the import companies made the best tires and tubes for the bicycle and motorcycle industries.
John
