Bicycle tires designated as 650C have a bead seat diameter of 571 millimeters. They are used on some cruisers, Schwinn and middleweight bicycles as well as time trial, triathlon and small road bikes. Schwinn called this size an S-7. Sizes include: 26x1-5/8, 26x1-3/4, 26x1, 26x3/4
Every Bicycle Tire,com "A Reference Resource & More.." 2012 
WHERE THE
TIRE IS THE "STAR"