Originally Posted by
Vintage Schwinn
The SCHWINN S5 and S6 rims are the exact same size.
The only difference between them is cosmetic, as the S5 has a slight raised hump in the center in the middle where the spokes are...............the S6 has a smooth portion there. The last year model that the S5 was seen on a Schwinn Collegiate was the 1972 model. The 1973 model Collegiate has the S6.
Interesting little tidbit there as I am an original owner of a Sept 1972 built Collegiate Sport (Sierra Brown). I just ran downstairs to check and indeed it has the S5 wheels. What build-date did the model-year typically change? I was thinking it might be like the automotive industry where the model year build-date change typically occurs in the August time-frame, and thus my bike would then be a 1973 model year. But that doesn't seem to be the case here.