Originally Posted by
SkepticalOne
Note I said 28c tires - not 28mm.
"28c" is gibberish shorthand for "700x28c" which is gibberish shorthand for 700c x 28mm, AKA a 700c tire that is 28mm wide. That is, a tire with a bead seat diameter of 622mm that inflates to 28mm wide. In a sane world, we would label such a tire something like 28 - 622.
Sometimes a "28c" tire won't inflate to exactly 28mm; different tires end up measuring slightly differently, and the rim width also affects inflated width.