Hi,

As I am learning about rims and its terminology, I am wondering how does the tire fit into the diagram below?

Is this a cross section view of the rim and center axle? or is it a top down view of the rim? or how do you read this?? any help will be appreciated.

 

That's a cross section of a rim, showing negative/positive offset, and the top part is the outside of the rim that the tire sits on. Hope that helps.