Wrote this last night, guess it was deleted for being not combine related. It is possible with 18.4x42s to not have the dual running down a corn row without a spacer installed. Our hub is at the very end of the axle, no spacer, we clear the row by a few inches. We aren't tracking a true 36" from the inner tire, but we also aren't hitting a corn row either. I can drive down rowed corn with the duals on and not run down any corn. Specs on our stuff, CIH 7220, 18.4x42s, 36" rows, trailed Kinze planter.