Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
285/75r20 vs 37/12.5r20 Tire Comparison Side By Side
  285/75-20 37/12.5-20 Difference
Diameter inches (mm) 36.83 (935.5) 37.03 (940.48) 0.2 (4.98) 0.5%
Width inches (mm) 11.22 (285) 12.52 (318) 1.3 (33) 11.6%
Circum. inches (mm) 115.71 (2938.96) 116.32 (2954.61) 0.62 (15.65) 0.5%
Sidewall Height inches (mm) 8.42 (213.75) 8.51 (216.24) 0.1 (2.49) 1.2%
Revolutions per mile (km) 547.59 (340.26) 544.69 (338.45) -2.9 (-1.8) -0.5%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.11 mph (32.36 km/h)
25 mph (40.23 km/h)25.13 mph (40.45 km/h)
30 mph (48.28 km/h)30.16 mph (48.54 km/h)
35 mph (56.33 km/h)35.19 mph (56.63 km/h)
40 mph (64.37 km/h)40.21 mph (64.72 km/h)
45 mph (72.42 km/h)45.24 mph (72.81 km/h)
50 mph (80.47 km/h)50.27 mph (80.9 km/h)
55 mph (88.51 km/h)55.29 mph (88.99 km/h)
60 mph (96.56 km/h)60.32 mph (97.07 km/h)
65 mph (104.61 km/h)65.35 mph (105.16 km/h)
70 mph (112.65 km/h)70.37 mph (113.25 km/h)
75 mph (120.7 km/h)75.4 mph (121.34 km/h)
80 mph (128.75 km/h)80.43 mph (129.43 km/h)
85 mph (136.79 km/h)85.45 mph (137.52 km/h)
90 mph (144.84 km/h)90.48 mph (145.61 km/h)
95 mph (152.89 km/h)95.51 mph (153.7 km/h)
100 mph (160.93 km/h)100.53 mph (161.79 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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