I still don't quite understand exactly how to measure ERD and why you can't use a tape. I don't know where to measure from. It isn't the maximum inside rim diameter (directly across the center to get the maximum).
I don't understand screwing the spokes into the nipples and then measuring? Measuring where? What good does that do? Again going back to the tape. There is no hub. I don't understand. I'm missing something here. I do a very good job as a bike mechanic and overall mechanic on everything, I have several college degrees in the sciences and engineering, my father was a contractor and then fixed everything at home. Fixing things is in my DNA and I still don't quite understand.
I don't know if anyone can explain how to measure ERD on this board or I will need to go to a bike shop and have them show it to me.