Originally Posted by
BlazingPedals
28" tires are how Europe refers to 700c, even though 700c is smaller than 27" tires. Why are they named 28" when they're actually smaller than 27"? Well, because 27" was already taken! Again, almost all of the regulars here know this stuff; but the ISO or ETRTO sizing is the only way to know for sure what the rim size is.
The response above was offered for a post asking about Raleigh roadster bikes with 28" wheels (28 x 1 1/2, as used on the Raleigh DL-1, for example). Clarification: 28 x 1 1/2 is not equivalent to 700c = 622; it's 635 and thus incompatible with 700c tires and wheels..