Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
145/70r12 vs 135/70r12 Tire Comparison Side By Side
  145/70-12 135/70-12 Difference
Diameter inches (mm) 19.99 (507.8) 19.44 (493.8) -0.55 (-14) -2.8%
Width inches (mm) 5.71 (145) 5.31 (135) -0.39 (-10) -6.9%
Circum. inches (mm) 62.81 (1595.3) 61.08 (1551.32) -1.73 (-43.98) -2.8%
Sidewall Height inches (mm) 4 (101.5) 3.72 (94.5) -0.28 (-7) -6.9%
Revolutions per mile (km) 1008.8 (626.84) 1037.4 (644.61) 28.6 (17.77) 2.8%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.45 mph (31.3 km/h)
25 mph (40.23 km/h)24.31 mph (39.12 km/h)
30 mph (48.28 km/h)29.17 mph (46.95 km/h)
35 mph (56.33 km/h)34.04 mph (54.77 km/h)
40 mph (64.37 km/h)38.9 mph (62.6 km/h)
45 mph (72.42 km/h)43.76 mph (70.42 km/h)
50 mph (80.47 km/h)48.62 mph (78.25 km/h)
55 mph (88.51 km/h)53.48 mph (86.07 km/h)
60 mph (96.56 km/h)58.35 mph (93.9 km/h)
65 mph (104.61 km/h)63.21 mph (101.72 km/h)
70 mph (112.65 km/h)68.07 mph (109.55 km/h)
75 mph (120.7 km/h)72.93 mph (117.37 km/h)
80 mph (128.75 km/h)77.79 mph (125.2 km/h)
85 mph (136.79 km/h)82.66 mph (133.02 km/h)
90 mph (144.84 km/h)87.52 mph (140.85 km/h)
95 mph (152.89 km/h)92.38 mph (148.67 km/h)
100 mph (160.93 km/h)97.24 mph (156.5 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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