Contour Enthusiasts Group Archives Forums General Troubleshooting Bad bad bad gas mileage

205/60 means 205 mm wide and height of sidewall is 60% of width or 123 mm. 123 mm is 4.84 inches so since the overall diameter involves two sidewalls it is about 9.68 inches plus the rim diameter of 16 so 25.68 inches in dameter over-all.

Stock is 185/70-14 which comes to 24.2 inches overall diameter. So you are only about 6% different from stock. When your odometer says you went 100 mi, you actually have gone about 106.