"28 inches" could be a 700C tire/tube, ISO622mm (an oddball designation for a common size) or a British roadster tire/tube, ISO635mm (a rare but not unknown size in the USA).
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It's not odd-ball at all but the only rational tire/rim sizing system in existance. When there are at least three 26" rims/tires, at least three 24" rim/tire and three 20" rim/tire combiantions, as well as 27", 700C, etc.,all different and incompatible, the ISO/ETRTO system is the only way to sort them out.