If you have removed the large center bolt, grab the wheel and wiggle and pull real hard. It will come off. All of the parts are strong, so don't be too worried about damaging anything. You also could try a little penetrating oil, like PB Blaster.
190SL, 230SL 5-speed, 95 E320 Wagon, 01 E320 Wagon, MGB, Boxster 'S', 190SL "Barn Find"