Is it what it is printed on the tire?
Or did you measure them?
Mine say "23x2.25" on my original tires, but when I measured the rim, it's at 19 inches.
I have some from motor west right now, so they're actually x2".
I looked and looked for 23 inch tires and never found them. Then I measured and found the rim-size to be 19 inch. Still hard to find, but I found them. Oh, and that's "diameter measurement" the 2 or 2.25 is how far they stand out from the rim.
You might already know that, but it took me a while to learn this, so I thought I'd pass it on.