Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
225/40r18 vs 225/55r16 Tire Comparison Side By Side
  225/40-18 225/55-16 Difference
Diameter inches (mm) 25.09 (637.2) 25.74 (653.9) 0.66 (16.7) 2.6%
Width inches (mm) 8.86 (225) 8.86 (225) 0 (0) 0%
Circum. inches (mm) 78.81 (2001.82) 80.88 (2054.29) 2.07 (52.46) 2.6%
Sidewall Height inches (mm) 3.54 (90) 4.87 (123.75) 1.33 (33.75) 37.5%
Revolutions per mile (km) 803.94 (499.54) 783.41 (486.79) -20.53 (-12.76) -2.6%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.52 mph (33.03 km/h)
25 mph (40.23 km/h)25.66 mph (41.29 km/h)
30 mph (48.28 km/h)30.79 mph (49.55 km/h)
35 mph (56.33 km/h)35.92 mph (57.8 km/h)
40 mph (64.37 km/h)41.05 mph (66.06 km/h)
45 mph (72.42 km/h)46.18 mph (74.32 km/h)
50 mph (80.47 km/h)51.31 mph (82.58 km/h)
55 mph (88.51 km/h)56.44 mph (90.83 km/h)
60 mph (96.56 km/h)61.57 mph (99.09 km/h)
65 mph (104.61 km/h)66.7 mph (107.35 km/h)
70 mph (112.65 km/h)71.83 mph (115.61 km/h)
75 mph (120.7 km/h)76.97 mph (123.86 km/h)
80 mph (128.75 km/h)82.1 mph (132.12 km/h)
85 mph (136.79 km/h)87.23 mph (140.38 km/h)
90 mph (144.84 km/h)92.36 mph (148.64 km/h)
95 mph (152.89 km/h)97.49 mph (156.89 km/h)
100 mph (160.93 km/h)102.62 mph (165.15 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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