Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
155/70r18 vs 225/55r18 Tire Comparison Side By Side
  155/70-18 225/55-18 Difference
Diameter inches (mm) 26.54 (674.2) 27.74 (704.7) 1.2 (30.5) 4.5%
Width inches (mm) 6.1 (155) 8.86 (225) 2.76 (70) 45.2%
Circum. inches (mm) 83.39 (2118.06) 87.16 (2213.88) 3.77 (95.82) 4.5%
Sidewall Height inches (mm) 4.27 (108.5) 4.87 (123.75) 0.6 (15.25) 14.1%
Revolutions per mile (km) 759.82 (472.13) 726.93 (451.69) -32.89 (-20.43) -4.3%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.9 mph (33.64 km/h)
25 mph (40.23 km/h)26.13 mph (42.05 km/h)
30 mph (48.28 km/h)31.36 mph (50.46 km/h)
35 mph (56.33 km/h)36.58 mph (58.88 km/h)
40 mph (64.37 km/h)41.81 mph (67.29 km/h)
45 mph (72.42 km/h)47.04 mph (75.7 km/h)
50 mph (80.47 km/h)52.26 mph (84.11 km/h)
55 mph (88.51 km/h)57.49 mph (92.52 km/h)
60 mph (96.56 km/h)62.71 mph (100.93 km/h)
65 mph (104.61 km/h)67.94 mph (109.34 km/h)
70 mph (112.65 km/h)73.17 mph (117.75 km/h)
75 mph (120.7 km/h)78.39 mph (126.16 km/h)
80 mph (128.75 km/h)83.62 mph (134.57 km/h)
85 mph (136.79 km/h)88.85 mph (142.98 km/h)
90 mph (144.84 km/h)94.07 mph (151.39 km/h)
95 mph (152.89 km/h)99.3 mph (159.8 km/h)
100 mph (160.93 km/h)104.52 mph (168.22 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
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