Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
255/50r18 vs 245/40r18 Tire Comparison Side By Side
  255/50-18 245/40-18 Difference
Diameter inches (mm) 28.04 (712.2) 25.72 (653.2) -2.32 (-59) -8.3%
Width inches (mm) 10.04 (255) 9.65 (245) -0.39 (-10) -3.9%
Circum. inches (mm) 88.09 (2237.44) 80.79 (2052.09) -7.3 (-185.35) -8.3%
Sidewall Height inches (mm) 5.02 (127.5) 3.86 (98) -1.16 (-29.5) -23.1%
Revolutions per mile (km) 719.28 (446.94) 784.25 (487.31) 64.97 (40.37) 9%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)18.34 mph (29.52 km/h)
25 mph (40.23 km/h)22.93 mph (36.9 km/h)
30 mph (48.28 km/h)27.51 mph (44.28 km/h)
35 mph (56.33 km/h)32.1 mph (51.66 km/h)
40 mph (64.37 km/h)36.69 mph (59.04 km/h)
45 mph (72.42 km/h)41.27 mph (66.42 km/h)
50 mph (80.47 km/h)45.86 mph (73.8 km/h)
55 mph (88.51 km/h)50.44 mph (81.18 km/h)
60 mph (96.56 km/h)55.03 mph (88.56 km/h)
65 mph (104.61 km/h)59.62 mph (95.94 km/h)
70 mph (112.65 km/h)64.2 mph (103.32 km/h)
75 mph (120.7 km/h)68.79 mph (110.7 km/h)
80 mph (128.75 km/h)73.37 mph (118.08 km/h)
85 mph (136.79 km/h)77.96 mph (125.46 km/h)
90 mph (144.84 km/h)82.54 mph (132.84 km/h)
95 mph (152.89 km/h)87.13 mph (140.22 km/h)
100 mph (160.93 km/h)91.72 mph (147.6 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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