Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
155/70r12 vs 145/80r12 Tire Comparison Side By Side
  155/70-12 145/80-12 Difference
Diameter inches (mm) 20.54 (521.8) 21.13 (536.8) 0.59 (15) 2.9%
Width inches (mm) 6.1 (155) 5.71 (145) -0.39 (-10) -6.5%
Circum. inches (mm) 64.54 (1639.28) 66.39 (1686.41) 1.86 (47.12) 2.9%
Sidewall Height inches (mm) 4.27 (108.5) 4.57 (116) 0.3 (7.5) 6.9%
Revolutions per mile (km) 981.74 (610.02) 954.3 (592.98) -27.43 (-17.05) -2.8%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.57 mph (33.11 km/h)
25 mph (40.23 km/h)25.72 mph (41.39 km/h)
30 mph (48.28 km/h)30.86 mph (49.67 km/h)
35 mph (56.33 km/h)36.01 mph (57.95 km/h)
40 mph (64.37 km/h)41.15 mph (66.22 km/h)
45 mph (72.42 km/h)46.29 mph (74.5 km/h)
50 mph (80.47 km/h)51.44 mph (82.78 km/h)
55 mph (88.51 km/h)56.58 mph (91.06 km/h)
60 mph (96.56 km/h)61.72 mph (99.34 km/h)
65 mph (104.61 km/h)66.87 mph (107.61 km/h)
70 mph (112.65 km/h)72.01 mph (115.89 km/h)
75 mph (120.7 km/h)77.16 mph (124.17 km/h)
80 mph (128.75 km/h)82.3 mph (132.45 km/h)
85 mph (136.79 km/h)87.44 mph (140.73 km/h)
90 mph (144.84 km/h)92.59 mph (149 km/h)
95 mph (152.89 km/h)97.73 mph (157.28 km/h)
100 mph (160.93 km/h)102.87 mph (165.56 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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