about 45mm, tire profile is D shaped , then... Got them 25 years ago, laced in a drum brake Hub set.

they're on a semi Beater MTB.. Here I only need the bike for a few weeks an occasional year..

It's not like MN .

Now they drill them Off center when requested ..

That would be better , with my Drum -freewheel hub ... S-A has a Drum Cassette hub now too ..
and 3 different IGH 3, 5 & 8 speed.

Here , the local use the 3 speed would do.

NB all Weather Sports , they also use the same extrusion in 29er diameters too ..