I don't know what the exact measurement is where I moved it off hand. I just made sure there was plenty of material to drill the new hole. I am running 8in rears. I can't seem to remember the offset axel brand right now. I got it from Rich on this site. I have had aheck of a time getting enough track adjustment, but I can't blame it all on the axel and wheels. Some of the mounting points were not quite right originally.