Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
285/50r18 vs 285/50r20 Tire Comparison Side By Side
  285/50-18 285/50-20 Difference
Diameter inches (mm) 29.22 (742.2) 31.22 (793) 2 (50.8) 6.8%
Width inches (mm) 11.22 (285) 11.22 (285) 0 (0) 0%
Circum. inches (mm) 91.8 (2331.69) 98.08 (2491.28) 6.28 (159.59) 6.8%
Sidewall Height inches (mm) 5.61 (142.5) 5.61 (142.5) 0 (0) 0%
Revolutions per mile (km) 690.2 (428.87) 645.99 (401.4) -44.21 (-27.47) -6.4%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)21.37 mph (34.39 km/h)
25 mph (40.23 km/h)26.71 mph (42.99 km/h)
30 mph (48.28 km/h)32.05 mph (51.58 km/h)
35 mph (56.33 km/h)37.4 mph (60.18 km/h)
40 mph (64.37 km/h)42.74 mph (68.78 km/h)
45 mph (72.42 km/h)48.08 mph (77.38 km/h)
50 mph (80.47 km/h)53.42 mph (85.97 km/h)
55 mph (88.51 km/h)58.76 mph (94.57 km/h)
60 mph (96.56 km/h)64.11 mph (103.17 km/h)
65 mph (104.61 km/h)69.45 mph (111.77 km/h)
70 mph (112.65 km/h)74.79 mph (120.36 km/h)
75 mph (120.7 km/h)80.13 mph (128.96 km/h)
80 mph (128.75 km/h)85.48 mph (137.56 km/h)
85 mph (136.79 km/h)90.82 mph (146.16 km/h)
90 mph (144.84 km/h)96.16 mph (154.75 km/h)
95 mph (152.89 km/h)101.5 mph (163.35 km/h)
100 mph (160.93 km/h)106.84 mph (171.95 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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