WHEEL/TIRE SIZE COMPARATOR Width   Profile   Rim - - - 175 185 195 205 215 225 235 245 255 265 275 285  /  - - - 30 35 40 45 50 55 60 65 70 75  -  - - - 13 14 15 16 17 18 19 20 Tire Width = Inches Tire Sidewall Height= Inches Wheel Diameter = Inches Wheel Circumfrence = Inches Width   Profile   Rim - - - 175 185 195 205 215 225 235 245 255 265 275 285  /  - - - 30 35 40 45 50 55 60 65 70 75  -  - - - 13 14 15 16 17 18 19 20 Tire Width = Inches Tire Sidewall Height= Inches Wheel Diameter = Inches Wheel Circumfrence = Inches The following information available after both wheel fields are filled Difference Between Sizes Tire Width = Inches Sidewall Height = Inches Wheel Diameter = Inches Wheel Circumfrence = Inches