Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
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145/70r12 vs 175/70r12 Tire Comparison Side By Side
  145/70-12 175/70-12 Difference
Diameter inches (mm) 19.99 (507.8) 21.65 (549.8) 1.65 (42) 8.3%
Width inches (mm) 5.71 (145) 6.89 (175) 1.18 (30) 20.7%
Circum. inches (mm) 62.81 (1595.3) 68 (1727.25) 5.19 (131.95) 8.3%
Sidewall Height inches (mm) 4 (101.5) 4.82 (122.5) 0.83 (21) 20.7%
Revolutions per mile (km) 1008.8 (626.84) 931.74 (578.95) -77.06 (-47.89) -7.6%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)21.65 mph (34.85 km/h)
25 mph (40.23 km/h)27.07 mph (43.56 km/h)
30 mph (48.28 km/h)32.48 mph (52.27 km/h)
35 mph (56.33 km/h)37.89 mph (60.99 km/h)
40 mph (64.37 km/h)43.31 mph (69.7 km/h)
45 mph (72.42 km/h)48.72 mph (78.41 km/h)
50 mph (80.47 km/h)54.14 mph (87.12 km/h)
55 mph (88.51 km/h)59.55 mph (95.84 km/h)
60 mph (96.56 km/h)64.96 mph (104.55 km/h)
65 mph (104.61 km/h)70.38 mph (113.26 km/h)
70 mph (112.65 km/h)75.79 mph (121.97 km/h)
75 mph (120.7 km/h)81.2 mph (130.68 km/h)
80 mph (128.75 km/h)86.62 mph (139.4 km/h)
85 mph (136.79 km/h)92.03 mph (148.11 km/h)
90 mph (144.84 km/h)97.44 mph (156.82 km/h)
95 mph (152.89 km/h)102.86 mph (165.53 km/h)
100 mph (160.93 km/h)108.27 mph (174.25 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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