Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
120/60r12 vs 100/70r12 Tire Comparison Side By Side
  120/60-12 100/70-12 Difference
Diameter inches (mm) 17.67 (448.8) 17.51 (444.8) -0.16 (-4) -0.9%
Width inches (mm) 4.72 (120) 3.94 (100) -0.79 (-20) -16.7%
Circum. inches (mm) 55.51 (1409.95) 55.01 (1397.38) -0.49 (-12.57) -0.9%
Sidewall Height inches (mm) 2.83 (72) 2.76 (70) -0.08 (-2) -2.8%
Revolutions per mile (km) 1141.42 (709.25) 1151.69 (715.62) 10.26 (6.38) 0.9%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.82 mph (31.9 km/h)
25 mph (40.23 km/h)24.78 mph (39.88 km/h)
30 mph (48.28 km/h)29.73 mph (47.85 km/h)
35 mph (56.33 km/h)34.69 mph (55.83 km/h)
40 mph (64.37 km/h)39.64 mph (63.8 km/h)
45 mph (72.42 km/h)44.6 mph (71.78 km/h)
50 mph (80.47 km/h)49.55 mph (79.75 km/h)
55 mph (88.51 km/h)54.51 mph (87.73 km/h)
60 mph (96.56 km/h)59.47 mph (95.7 km/h)
65 mph (104.61 km/h)64.42 mph (103.68 km/h)
70 mph (112.65 km/h)69.38 mph (111.65 km/h)
75 mph (120.7 km/h)74.33 mph (119.63 km/h)
80 mph (128.75 km/h)79.29 mph (127.6 km/h)
85 mph (136.79 km/h)84.24 mph (135.58 km/h)
90 mph (144.84 km/h)89.2 mph (143.55 km/h)
95 mph (152.89 km/h)94.15 mph (151.53 km/h)
100 mph (160.93 km/h)99.11 mph (159.5 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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