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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165/70r12 vs 185/60r12 Tire Comparison Side By Side
  165/70-12 185/60-12 Difference
Diameter inches (mm) 21.09 (535.8) 20.74 (526.8) -0.35 (-9) -1.7%
Width inches (mm) 6.5 (165) 7.28 (185) 0.79 (20) 12.1%
Circum. inches (mm) 66.27 (1683.27) 65.16 (1654.99) -1.11 (-28.27) -1.7%
Sidewall Height inches (mm) 4.55 (115.5) 4.37 (111) -0.18 (-4.5) -3.9%
Revolutions per mile (km) 956.08 (594.08) 972.42 (604.23) 16.33 (10.15) 1.7%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.66 mph (31.65 km/h)
25 mph (40.23 km/h)24.58 mph (39.56 km/h)
30 mph (48.28 km/h)29.5 mph (47.47 km/h)
35 mph (56.33 km/h)34.41 mph (55.38 km/h)
40 mph (64.37 km/h)39.33 mph (63.29 km/h)
45 mph (72.42 km/h)44.24 mph (71.2 km/h)
50 mph (80.47 km/h)49.16 mph (79.12 km/h)
55 mph (88.51 km/h)54.08 mph (87.03 km/h)
60 mph (96.56 km/h)58.99 mph (94.94 km/h)
65 mph (104.61 km/h)63.91 mph (102.85 km/h)
70 mph (112.65 km/h)68.82 mph (110.76 km/h)
75 mph (120.7 km/h)73.74 mph (118.67 km/h)
80 mph (128.75 km/h)78.66 mph (126.59 km/h)
85 mph (136.79 km/h)83.57 mph (134.5 km/h)
90 mph (144.84 km/h)88.49 mph (142.41 km/h)
95 mph (152.89 km/h)93.4 mph (150.32 km/h)
100 mph (160.93 km/h)98.32 mph (158.23 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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