ok fella's i was looking over the 2002 exmark and dixie catalogs. we all know exmarks 80% formula for acres an hour. dixie list ground speed at 10 mph and mowing speed at 8mph. alright what are your professional thoughts on these speed's minus the media spin. for example you have a 15 acre flat parcel, you are running 3 60" mowers. how long in therory will it take to complete this?