Differing tire sizes on tread and side wall While working on my bike the other day, I noticed that there's what appears to be a tire size on the tread. It says 27.5x2.35



Thing is ... this is a 29 inch tire. It also says so on the side wall, along with the respective ISO number (60-622)



This is a Schwalbe Hans Dampf that was factory-fitted on the bike by the manufacturer (Cube).
Full tire details as per Cube:
Schwalbe Hans Dampf, Addix Soft, Kevlar, Super Gravity, Tubeless Easy, 2.35

The front tire is a Schwalbe Magic Mary that has no such marking on the tread, just the correct details on the side wall.

Can someone explain this? An error in the mold in the Schwalbe factory perhabs? Or maybe the numbers mean something completely different?

It's not at all a problem for me. I know for a fact that this is a 29er bike with 29 inch wheels. I'm just curious.
Looks like an error to me - its either 29" or 27.5" with no ambiguity.   It is unusual to see details embedded in the tread, I've never seen it in person.

You could choose to highlight the correct size details with a white paint pen, and/or file the wrong marking off with some careful strokes of a file.   Or ride till it wears off :)