I print "regular" spoked wheels flat to the build plate on supports. That has worked great so far. I'm sure they can be printed at any angle with the correct amount of supports regardless but would take longer.
For wire wheels like the Maserati birdcage wire wheels, I printed them vertical, 90 degrees to the build plate on supports. This is to stop the "wires" buckling during the print which did happen when I tried to print them flat. I learned from some other peoples experience on facebook.
I'm still new to the 3d printing game, but these ways have worked well for me.
Mike