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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100/100r12 vs 90/90r12 Tire Comparison Side By Side
  100/100-12 90/90-12 Difference
Diameter inches (mm) 19.87 (504.8) 18.38 (466.8) -1.5 (-38) -7.5%
Width inches (mm) 3.94 (100) 3.54 (90) -0.39 (-10) -10%
Circum. inches (mm) 62.44 (1585.88) 57.74 (1466.5) -4.7 (-119.38) -7.5%
Sidewall Height inches (mm) 3.94 (100) 3.19 (81) -0.75 (-19) -19%
Revolutions per mile (km) 1014.8 (630.57) 1097.41 (681.9) 82.61 (51.33) 8.1%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)18.49 mph (29.76 km/h)
25 mph (40.23 km/h)23.12 mph (37.2 km/h)
30 mph (48.28 km/h)27.74 mph (44.65 km/h)
35 mph (56.33 km/h)32.37 mph (52.09 km/h)
40 mph (64.37 km/h)36.99 mph (59.53 km/h)
45 mph (72.42 km/h)41.61 mph (66.97 km/h)
50 mph (80.47 km/h)46.24 mph (74.41 km/h)
55 mph (88.51 km/h)50.86 mph (81.85 km/h)
60 mph (96.56 km/h)55.48 mph (89.29 km/h)
65 mph (104.61 km/h)60.11 mph (96.73 km/h)
70 mph (112.65 km/h)64.73 mph (104.17 km/h)
75 mph (120.7 km/h)69.35 mph (111.61 km/h)
80 mph (128.75 km/h)73.98 mph (119.06 km/h)
85 mph (136.79 km/h)78.6 mph (126.5 km/h)
90 mph (144.84 km/h)83.23 mph (133.94 km/h)
95 mph (152.89 km/h)87.85 mph (141.38 km/h)
100 mph (160.93 km/h)92.47 mph (148.82 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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