I have the DB 2 1/2in. spinner on mine, and I am using a 14 in. prop and it fits fine. It also comes with spacers that will allow you to use the spinner on dif size shafts. You must use the short prop nut adapter that is seperate from the spinner. For the money you think they would supply you with one. Had no balance problems with mine, and it looks real nice if you take the time to polish it up.