Had a bit of time today and a few new tyres to try out for size/volume. I’ve measured to the carcass in all all cases and height includes the depth of the rim (it was easier that way).
650b+ on a Sun Mulefut rim.
Fat B Nimble – 3.5!!! – 73mm wide, 76mm high – I have tried this but can’t remember how it rode, didn’t die if that helps.
WTB Trailblazer – 2.8 – 68mm wide, 74mm high – been out in the slop on this today as rear tyre, was ok but did spin out a couple of times.
Duro Crux – 3.5 – 74mm wide, 79mm high – feels heavy in your hand and looks massive, does have very big and square knobs not a million miles away from a dirt wizard.
Chaoyang Big Daay – 3.5 – 72mm wide, 79mm high – feels quite light with pretty small knobs, might be better suited for summer use?
I went out on my El Mariachi in 97.5+ mode this morning, had a Chupacabra on the front which did very well in the mud even though it seemed to clog up very easily. As others have said I do not see how the manufacturers come up with the tyre sizes apart from tossing a coin?