Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
250/40r18 vs 250/40r20 Tire Comparison Side By Side
  250/40-18 250/40-20 Difference
Diameter inches (mm) 25.87 (657.2) 27.87 (708) 2 (50.8) 7.7%
Width inches (mm) 9.84 (250) 9.84 (250) 0 (0) 0%
Circum. inches (mm) 81.29 (2064.65) 87.57 (2224.25) 6.28 (159.59) 7.7%
Sidewall Height inches (mm) 3.94 (100) 3.94 (100) 0 (0) 0%
Revolutions per mile (km) 779.47 (484.34) 723.55 (449.59) -55.93 (-34.75) -7.2%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)21.55 mph (34.67 km/h)
25 mph (40.23 km/h)26.93 mph (43.34 km/h)
30 mph (48.28 km/h)32.32 mph (52.01 km/h)
35 mph (56.33 km/h)37.71 mph (60.68 km/h)
40 mph (64.37 km/h)43.09 mph (69.35 km/h)
45 mph (72.42 km/h)48.48 mph (78.02 km/h)
50 mph (80.47 km/h)53.86 mph (86.69 km/h)
55 mph (88.51 km/h)59.25 mph (95.36 km/h)
60 mph (96.56 km/h)64.64 mph (104.02 km/h)
65 mph (104.61 km/h)70.02 mph (112.69 km/h)
70 mph (112.65 km/h)75.41 mph (121.36 km/h)
75 mph (120.7 km/h)80.8 mph (130.03 km/h)
80 mph (128.75 km/h)86.18 mph (138.7 km/h)
85 mph (136.79 km/h)91.57 mph (147.37 km/h)
90 mph (144.84 km/h)96.96 mph (156.04 km/h)
95 mph (152.89 km/h)102.34 mph (164.71 km/h)
100 mph (160.93 km/h)107.73 mph (173.37 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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