The fall draft horse sale at Topeka, IN is in the books and I came home with a new to me McCormick end gate seeder. It is in excellent shape and has been well cared for. Has both ferterlizer and seed hooper with 2 spreader wheels. At this time , I figure to mount it on a rubber tire wagon that we use to drive on when getting ready for the shows. I will build a rubber tire drive wheel to run off one of the rear wheels of the wagon. Any one have any real simple formula for converting the ground covered by the wagon wheel to the rpm’s of the drive wheel to the size of the drive gear to run the gear on the seeder to get the right rpm of the spreader wheels. HHHmmmmm. There might be some guess work in this project.