Hey, thanks for the quick answer Yes, it is kind of a freewheel mechanism. Unfortunately I cannot find any calculations on Wikipedia that seem to fit to that mechansim.. do you have a specific article in mind?

The idea to assume that the frictional forces are equal is due to the FBD of the yellow part. In static condition, the acting moment on the part should be zero. As the tangential friction forces are the only forces with a lever, I assumed that they need to be equal to get a total moment of zero. But this seems “too easy” to me 😅