BlackEclipse
03-25-2008, 08:43 PM
The following chart is based upon a stock tire size of 205 55R16. It shows different rim sizes and aspect ratios which will allow you to choose the correct tire to maintain the same stock tire circumference which will keep your speedometer accurate on your car.
Width Percent Rim Size Circumference Off By mph off *rph
(mm) (in.) (mm) (mm) at 65mph @ 65mph
----- ------- -------- ------------- ------- --------- ----------
205 55 16 1985.17 0.00 0.00 52694.3454 (Stock)
215 55 16 2019.73 34.56 1.13
225 55 16 2054.29 69.12 2.26
225 50 16 1983.60 -1.57 -0.05
245 50 16 2046.43 61.26 2.01
255 50 16 2077.85 92.68 3.03
205 45 16 1856.37 -128.81 -4.22
245 45 16 1969.46 -15.71 -0.51
225 40 16 1842.23 -142.94 -4.68
225 40 17 1922.03 -63.15 -2.07
205 50 17 2000.57 15.39 0.50
215 50 17 2031.98 46.81 1.53
225 50 17 2063.40 78.23 2.56
215 45 17 1964.44 -20.73 -0.68
225 45 17 1992.71 7.54 0.25 <-- Closest in 17"
235 45 17 2020.99 35.81 1.17
245 45 17 2049.26 64.09 2.10
215 40 17 1896.89 -88.28 -2.89
235 40 17 1947.16 -38.01 -1.24
245 40 17 1972.29 -12.88 -0.42
255 40 17 1997.42 12.25 0.40
*rph = rotations per hour of wheel at 65 mph
As you can see from the above graph, 225 45R17 is the optimal tire size for 17 inch rims. Your actual speed at 65mph will be 65.25 mph with these tires.
Width Percent Rim Size Circumference Off By mph off *rph
(mm) (in.) (mm) (mm) at 65mph @ 65mph
----- ------- -------- ------------- ------- --------- ----------
205 55 16 1985.17 0.00 0.00 52694.3454 (Stock)
215 55 16 2019.73 34.56 1.13
225 55 16 2054.29 69.12 2.26
225 50 16 1983.60 -1.57 -0.05
245 50 16 2046.43 61.26 2.01
255 50 16 2077.85 92.68 3.03
205 45 16 1856.37 -128.81 -4.22
245 45 16 1969.46 -15.71 -0.51
225 40 16 1842.23 -142.94 -4.68
225 40 17 1922.03 -63.15 -2.07
205 50 17 2000.57 15.39 0.50
215 50 17 2031.98 46.81 1.53
225 50 17 2063.40 78.23 2.56
215 45 17 1964.44 -20.73 -0.68
225 45 17 1992.71 7.54 0.25 <-- Closest in 17"
235 45 17 2020.99 35.81 1.17
245 45 17 2049.26 64.09 2.10
215 40 17 1896.89 -88.28 -2.89
235 40 17 1947.16 -38.01 -1.24
245 40 17 1972.29 -12.88 -0.42
255 40 17 1997.42 12.25 0.40
*rph = rotations per hour of wheel at 65 mph
As you can see from the above graph, 225 45R17 is the optimal tire size for 17 inch rims. Your actual speed at 65mph will be 65.25 mph with these tires.