Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
225/50r18 vs 245/40r18 Tire Comparison Side By Side
  225/50-18 245/40-18 Difference
Diameter inches (mm) 26.86 (682.2) 25.72 (653.2) -1.14 (-29) -4.3%
Width inches (mm) 8.86 (225) 9.65 (245) 0.79 (20) 8.9%
Circum. inches (mm) 84.38 (2143.19) 80.79 (2052.09) -3.59 (-91.11) -4.3%
Sidewall Height inches (mm) 4.43 (112.5) 3.86 (98) -0.57 (-14.5) -12.9%
Revolutions per mile (km) 750.91 (466.59) 784.25 (487.31) 33.34 (20.72) 4.4%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.15 mph (30.82 km/h)
25 mph (40.23 km/h)23.94 mph (38.52 km/h)
30 mph (48.28 km/h)28.72 mph (46.23 km/h)
35 mph (56.33 km/h)33.51 mph (53.93 km/h)
40 mph (64.37 km/h)38.3 mph (61.64 km/h)
45 mph (72.42 km/h)43.09 mph (69.34 km/h)
50 mph (80.47 km/h)47.87 mph (77.05 km/h)
55 mph (88.51 km/h)52.66 mph (84.75 km/h)
60 mph (96.56 km/h)57.45 mph (92.46 km/h)
65 mph (104.61 km/h)62.24 mph (100.16 km/h)
70 mph (112.65 km/h)67.02 mph (107.87 km/h)
75 mph (120.7 km/h)71.81 mph (115.57 km/h)
80 mph (128.75 km/h)76.6 mph (123.27 km/h)
85 mph (136.79 km/h)81.39 mph (130.98 km/h)
90 mph (144.84 km/h)86.17 mph (138.68 km/h)
95 mph (152.89 km/h)90.96 mph (146.39 km/h)
100 mph (160.93 km/h)95.75 mph (154.09 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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