Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
225/30r20 vs 225/45r17 Tire Comparison Side By Side
  225/30-20 225/45-17 Difference
Diameter inches (mm) 25.31 (643) 24.97 (634.3) -0.34 (-8.7) -1.4%
Width inches (mm) 8.86 (225) 8.86 (225) 0 (0) 0%
Circum. inches (mm) 79.53 (2020.04) 78.45 (1992.71) -1.08 (-27.33) -1.4%
Sidewall Height inches (mm) 2.66 (67.5) 3.99 (101.25) 1.33 (33.75) 50%
Revolutions per mile (km) 796.69 (495.04) 807.61 (501.83) 10.93 (6.79) 1.4%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.73 mph (31.75 km/h)
25 mph (40.23 km/h)24.66 mph (39.69 km/h)
30 mph (48.28 km/h)29.59 mph (47.63 km/h)
35 mph (56.33 km/h)34.53 mph (55.57 km/h)
40 mph (64.37 km/h)39.46 mph (63.5 km/h)
45 mph (72.42 km/h)44.39 mph (71.44 km/h)
50 mph (80.47 km/h)49.32 mph (79.38 km/h)
55 mph (88.51 km/h)54.26 mph (87.32 km/h)
60 mph (96.56 km/h)59.19 mph (95.25 km/h)
65 mph (104.61 km/h)64.12 mph (103.19 km/h)
70 mph (112.65 km/h)69.05 mph (111.13 km/h)
75 mph (120.7 km/h)73.99 mph (119.07 km/h)
80 mph (128.75 km/h)78.92 mph (127.01 km/h)
85 mph (136.79 km/h)83.85 mph (134.94 km/h)
90 mph (144.84 km/h)88.78 mph (142.88 km/h)
95 mph (152.89 km/h)93.71 mph (150.82 km/h)
100 mph (160.93 km/h)98.65 mph (158.76 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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