Wheel Offset expalined?
 

Could somebody expain what exactly is wheel offset, and where it is measured from?

The distance between the mounting surface on the hub and the center of the wheel.
When you add a spacer the offset/et is reduced by the spacer size because you're moving the center of the wheel closer to the mounting surface on the hub.

I actually struggled for a bit with understanding offset. Now I has it undr control. :)