Schwinn S-7 tires
Schwinn 26 Inch Middleweight bicycles from the 50s, 60s and 70s used a wheelsize that is the same as more current 650C triathlon and small adult road bikes, but the tires are not interchangeable. The Schwinn S-7 tires use a fractional width measurement (e.g. 1 3/4") instead of a decimal width measurement (e.g. 1.4" or 28mm).
We offer one replacement tire for these Schwinn cruiser bikes. The Kenda K75 S-7 Schwinn 26 Inch Tire (571) is 26x1 3/4".