John E. brings up an important point, as you also may want to investigate as to which tire brands run more true to size and which do not(--run smaller width--)
Michelin Protek (32 x 630) 27" x 1 1/4 tire is probably among the wider ones, as most cheat.....
(This is a great tire, however it's weight in grams is among the heavier tires in that size..................)