Maybe I should add, I listed only the size of the 16" tires. The full designation would be LT215/75R16E, where "LT" means Light Truck not Passenger (P) and E is the Load Range. There might be Load Range "D" tires in that size, but they're pretty much gone.
Also, Barry's uses the words "Dual Spacing" for what's also known as "Offset." It's the same thing, and that thing is NOT the gap between the sidewalls. It's the design of the wheels that creates that spacing. As an example the 10.2" Dual Spacing/Offset means 10.2" between the centers of the rims of two wheels. If you can measure/mark the center(3" on a "six inch rim") then put the rim face down on a flat surface. Measure carefully and it should be 5.1" from surface to your rim center mark. That adds to 10.2" and provides the right clearance for LT225/75R16E tires. That's the size, BTW, that's used on most newer Class C's.