Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
37/11.5r20 vs 37/12.5r20 Tire Comparison Side By Side
  37/11.5-20 37/12.5-20 Difference
Diameter inches (mm) 37.01 (940.16) 37.03 (940.48) 0.01 (0.32) 0%
Width inches (mm) 11.5 (292) 12.52 (318) 1.02 (26) 8.9%
Circum. inches (mm) 116.28 (2953.6) 116.32 (2954.61) 0.04 (1.01) 0%
Sidewall Height inches (mm) 8.51 (216.08) 8.51 (216.24) 0.01 (0.16) 0.1%
Revolutions per mile (km) 544.88 (338.57) 544.69 (338.45) -0.19 (-0.12) -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 (40.25 km/h)
30 mph (48.28 km/h)30.01 mph (48.3 km/h)
35 mph (56.33 km/h)35.01 mph (56.35 km/h)
40 mph (64.37 km/h)40.01 mph (64.4 km/h)
45 mph (72.42 km/h)45.02 mph (72.45 km/h)
50 mph (80.47 km/h)50.02 mph (80.49 km/h)
55 mph (88.51 km/h)55.02 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 (104.64 km/h)
70 mph (112.65 km/h)70.02 mph (112.69 km/h)
75 mph (120.7 km/h)75.03 mph (120.74 km/h)
80 mph (128.75 km/h)80.03 mph (128.79 km/h)
85 mph (136.79 km/h)85.03 mph (136.84 km/h)
90 mph (144.84 km/h)90.03 mph (144.89 km/h)
95 mph (152.89 km/h)95.03 mph (152.94 km/h)
100 mph (160.93 km/h)100.03 mph (160.99 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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