Originally Posted by
noglider
It is pretty dumb that 650B got informally named 27.5. It's smaller than the 26" wheel of the 3-speed variety, aka 26x1-3/8" aka 590. 590 is smaller than 622 (700c), which is smaller than 27" (630), so 27.5 is a particularly dumb name.
I dunno what it says about my brain, but I can understand it -- a 584mm rim with ~2" MTB tires on it will be about halfway between the diameters of a 26" and 29" wheel, so they split the difference.
That said, I've converted my thinking almost completely to ISO/ETRTO, and only translate to fit in with the discussion at hand. As for the OP, I'm voting to stay with 559mm rims -- tire selection has never been better than it is now for supple, "slick" tires in that size, and wheels are easy to come by.
