Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
245/45r18 vs 225/45r18 Tire Comparison Side By Side
  245/45-18 225/45-18 Difference
Diameter inches (mm) 26.68 (677.7) 25.97 (659.7) -0.71 (-18) -2.7%
Width inches (mm) 9.65 (245) 8.86 (225) -0.79 (-20) -8.2%
Circum. inches (mm) 83.82 (2129.06) 81.59 (2072.51) -2.23 (-56.55) -2.7%
Sidewall Height inches (mm) 4.34 (110.25) 3.99 (101.25) -0.35 (-9) -8.2%
Revolutions per mile (km) 755.9 (469.69) 776.52 (482.51) 20.62 (12.82) 2.7%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.47 mph (31.33 km/h)
25 mph (40.23 km/h)24.34 mph (39.17 km/h)
30 mph (48.28 km/h)29.2 mph (47 km/h)
35 mph (56.33 km/h)34.07 mph (54.83 km/h)
40 mph (64.37 km/h)38.94 mph (62.66 km/h)
45 mph (72.42 km/h)43.8 mph (70.5 km/h)
50 mph (80.47 km/h)48.67 mph (78.33 km/h)
55 mph (88.51 km/h)53.54 mph (86.16 km/h)
60 mph (96.56 km/h)58.41 mph (94 km/h)
65 mph (104.61 km/h)63.27 mph (101.83 km/h)
70 mph (112.65 km/h)68.14 mph (109.66 km/h)
75 mph (120.7 km/h)73.01 mph (117.5 km/h)
80 mph (128.75 km/h)77.88 mph (125.33 km/h)
85 mph (136.79 km/h)82.74 mph (133.16 km/h)
90 mph (144.84 km/h)87.61 mph (140.99 km/h)
95 mph (152.89 km/h)92.48 mph (148.83 km/h)
100 mph (160.93 km/h)97.34 mph (156.66 km/h)

Gear Ratio / RPMs for New Tire (@ 65 mph)
2.35 2.73 2.94 3.07 3.21 3.31 3.42 3.55 3.73 3.91 4.11 4.27 4.56 4.88 5.13 5.29 5.38 5.71 6.17 7.17
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