6 inch wide wheels suit narrow tires and lightweight cars where fuel economy matters more than grip. This width appears most often on 15 inch, 16 inch, 14 inch wheels, and it is sized for 165 to 195 mm tires.
We list 561 wheels at this width. Width is what limits your tire choice: mount a tire that is too wide and the sidewall bulges, too narrow and the rim edge takes the hits. If you are between two widths, go with the one inside the tire manufacturer's recommended rim range.