Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
120/70r12 vs 100/90r12 Tire Comparison Side By Side
  120/70-12 100/90-12 Difference
Diameter inches (mm) 18.61 (472.8) 19.09 (484.8) 0.47 (12) 2.5%
Width inches (mm) 4.72 (120) 3.94 (100) -0.79 (-20) -16.7%
Circum. inches (mm) 58.48 (1485.35) 59.96 (1523.04) 1.48 (37.7) 2.5%
Sidewall Height inches (mm) 3.31 (84) 3.54 (90) 0.24 (6) 7.1%
Revolutions per mile (km) 1083.48 (673.24) 1056.66 (656.58) -26.82 (-16.66) -2.5%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.51 mph (33 km/h)
25 mph (40.23 km/h)25.63 mph (41.25 km/h)
30 mph (48.28 km/h)30.76 mph (49.51 km/h)
35 mph (56.33 km/h)35.89 mph (57.76 km/h)
40 mph (64.37 km/h)41.02 mph (66.01 km/h)
45 mph (72.42 km/h)46.14 mph (74.26 km/h)
50 mph (80.47 km/h)51.27 mph (82.51 km/h)
55 mph (88.51 km/h)56.4 mph (90.76 km/h)
60 mph (96.56 km/h)61.52 mph (99.01 km/h)
65 mph (104.61 km/h)66.65 mph (107.26 km/h)
70 mph (112.65 km/h)71.78 mph (115.51 km/h)
75 mph (120.7 km/h)76.9 mph (123.76 km/h)
80 mph (128.75 km/h)82.03 mph (132.02 km/h)
85 mph (136.79 km/h)87.16 mph (140.27 km/h)
90 mph (144.84 km/h)92.28 mph (148.52 km/h)
95 mph (152.89 km/h)97.41 mph (156.77 km/h)
100 mph (160.93 km/h)102.54 mph (165.02 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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