Originally Posted by Sheldon Brown
No. Yes.
622 mm (700c) tires will not fit onto 630 mm (27 inch) rims. No way.
622 mm (700c) wheels and tires will fit on a bike made for 630 mm (27 inch) wheels, but you will need to be able to lower the brake shoes by 4 mm. Depending on your bike and your brake calipers, there may or may not be enough adjustment room available. That's the only problem with this conversion.
Sheldon "ISO/E.T.R.T.O." Brown
Thanks! That's the answer/ perspective I was looking for! As usual, you rock!