Originally Posted by
alcjphil
Welcome to the arcane world of bicycle tire sizes. The best article ever about tire sizing and how a 29" tire fits on a rim too small for a 27" tire and how a 28" tire needs a rim too big for either
https://www.sheldonbrown.com/tire-sizing.html
tl;dr version: just use the ISO/ETRTO tire and rim designations instead of the various arcane numbers.
An ETRTO tire designation will look something like this: 35-622, where the first number is the nominal width of the tire and the second is the tire bead seat diameter. If you're trying to figure out what tire will fit on your rim, the second number is the one to look at. If the bead seat diameter doesn't match, the tire won't fit your rim. Period. Full stop. Rims can accommodate a fairly wide range of tire widths, with the limiting factor usually being frame clearance.