Started with an excellent tractor tire STL from Ethan Fehrman on Thingiverse, reduced the size to 45% and stacked them side by side in the slicer and overlapped them a little bit to make them appear to be one piece. Exported this assembly as STL which made them one piece. Rotated it to stand up and added a disk to the bottom for the floor, again exporting the assembly to make it intact. Ran the result through 3D Builder to fix anomalies left over, saved the result and printed it on my Ender3 with direct drive using PLA at 0.28 layer height, 80mm/s, 195C nozzle, 55C bed. Took about eleven hours to complete.