Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
255/55r20 vs 255/65r18 Tire Comparison Side By Side
  255/55-20 255/65-18 Difference
Diameter inches (mm) 31.04 (788.5) 31.05 (788.7) 0.01 (0.2) 0%
Width inches (mm) 10.04 (255) 10.04 (255) 0 (0) 0%
Circum. inches (mm) 97.53 (2477.15) 97.55 (2477.77) 0.02 (0.63) 0%
Sidewall Height inches (mm) 5.52 (140.25) 6.53 (165.75) 1 (25.5) 18.2%
Revolutions per mile (km) 649.68 (403.69) 649.51 (403.59) -0.16 (-0.1) -0%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.01 mph (32.2 km/h)
25 mph (40.23 km/h)25.01 mph (40.24 km/h)
30 mph (48.28 km/h)30.01 mph (48.29 km/h)
35 mph (56.33 km/h)35.01 mph (56.34 km/h)
40 mph (64.37 km/h)40.01 mph (64.39 km/h)
45 mph (72.42 km/h)45.01 mph (72.44 km/h)
50 mph (80.47 km/h)50.01 mph (80.49 km/h)
55 mph (88.51 km/h)55.01 mph (88.54 km/h)
60 mph (96.56 km/h)60.02 mph (96.59 km/h)
65 mph (104.61 km/h)65.02 mph (104.63 km/h)
70 mph (112.65 km/h)70.02 mph (112.68 km/h)
75 mph (120.7 km/h)75.02 mph (120.73 km/h)
80 mph (128.75 km/h)80.02 mph (128.78 km/h)
85 mph (136.79 km/h)85.02 mph (136.83 km/h)
90 mph (144.84 km/h)90.02 mph (144.88 km/h)
95 mph (152.89 km/h)95.02 mph (152.93 km/h)
100 mph (160.93 km/h)100.03 mph (160.98 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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