Hey C Dub,
Even though it's listed as a solid, you have some errant surfaces stacked and rendering it an improper solid....

Here is a file. the red surfaces can be deleted, which will leave 2 holes to fill (use naked edges and run network on the 2 open holes)



I separate the inner surface and hide it. Select the 2 surfaces and delete. Then unhide and join to a joined surface. Then naked edges and fill and join to a solid. The 3dm file contains a tire that will Boolean...