Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
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100/80r12 vs 90/90r12 Tire Comparison Side By Side
  100/80-12 90/90-12 Difference
Diameter inches (mm) 18.3 (464.8) 18.38 (466.8) 0.08 (2) 0.4%
Width inches (mm) 3.94 (100) 3.54 (90) -0.39 (-10) -10%
Circum. inches (mm) 57.49 (1460.21) 57.74 (1466.5) 0.25 (6.28) 0.4%
Sidewall Height inches (mm) 3.15 (80) 3.19 (81) 0.04 (1) 1.3%
Revolutions per mile (km) 1102.13 (684.83) 1097.41 (681.9) -4.72 (-2.93) -0.4%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.09 mph (32.33 km/h)
25 mph (40.23 km/h)25.11 mph (40.41 km/h)
30 mph (48.28 km/h)30.13 mph (48.49 km/h)
35 mph (56.33 km/h)35.15 mph (56.57 km/h)
40 mph (64.37 km/h)40.17 mph (64.65 km/h)
45 mph (72.42 km/h)45.19 mph (72.73 km/h)
50 mph (80.47 km/h)50.22 mph (80.81 km/h)
55 mph (88.51 km/h)55.24 mph (88.89 km/h)
60 mph (96.56 km/h)60.26 mph (96.98 km/h)
65 mph (104.61 km/h)65.28 mph (105.06 km/h)
70 mph (112.65 km/h)70.3 mph (113.14 km/h)
75 mph (120.7 km/h)75.32 mph (121.22 km/h)
80 mph (128.75 km/h)80.34 mph (129.3 km/h)
85 mph (136.79 km/h)85.37 mph (137.38 km/h)
90 mph (144.84 km/h)90.39 mph (145.46 km/h)
95 mph (152.89 km/h)95.41 mph (153.55 km/h)
100 mph (160.93 km/h)100.43 mph (161.63 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
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
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