If you have new tires, you most likely have newer wheels, as only truck
and farm implement dealers will touch a split rim wheel nowadays. Here
is a split-rim:
http://vintageairstream.com/floyd/brakes/brakes,b4tire.jpg
You can barely see the ring near the outside of the wheel diameter.
Another way to tell is the hub caps had spring clips that mounted inside
the hub opening - newer hub caps catch over 3 tangs on the wheel hub
opening.
Best of luck,
RJ