Originally Posted by
FBinNY
Most likely defect is the wrong word here. These are build as super tight frames for 700c wheels, and odds are that the issue isn't that 700c wheels won't fit, but that they'll fit only with tires smaller than 25mm (or less).
If you search for a photo of the frame or bike, you'll see the near zero clearance behind the seat tube, which is cut away to follw the curve of the wheel, with no room to spare.
The difference in diameter between a 650c wheel and a 700 c wheel is 51mm, which would drop the bottom bracket by about 1" and also increase brake reach by the same amount