Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
235/45r17 vs 245/40r18 Tire Comparison Side By Side
  235/45-17 245/40-18 Difference
Diameter inches (mm) 25.33 (643.3) 25.72 (653.2) 0.39 (9.9) 1.5%
Width inches (mm) 9.25 (235) 9.65 (245) 0.39 (10) 4.3%
Circum. inches (mm) 79.57 (2020.99) 80.79 (2052.09) 1.22 (31.1) 1.5%
Sidewall Height inches (mm) 4.16 (105.75) 3.86 (98) -0.31 (-7.75) -7.3%
Revolutions per mile (km) 796.32 (494.81) 784.25 (487.31) -12.07 (-7.5) -1.5%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.31 mph (32.68 km/h)
25 mph (40.23 km/h)25.38 mph (40.85 km/h)
30 mph (48.28 km/h)30.46 mph (49.02 km/h)
35 mph (56.33 km/h)35.54 mph (57.19 km/h)
40 mph (64.37 km/h)40.62 mph (65.36 km/h)
45 mph (72.42 km/h)45.69 mph (73.54 km/h)
50 mph (80.47 km/h)50.77 mph (81.71 km/h)
55 mph (88.51 km/h)55.85 mph (89.88 km/h)
60 mph (96.56 km/h)60.92 mph (98.05 km/h)
65 mph (104.61 km/h)66 mph (106.22 km/h)
70 mph (112.65 km/h)71.08 mph (114.39 km/h)
75 mph (120.7 km/h)76.15 mph (122.56 km/h)
80 mph (128.75 km/h)81.23 mph (130.73 km/h)
85 mph (136.79 km/h)86.31 mph (138.9 km/h)
90 mph (144.84 km/h)91.39 mph (147.07 km/h)
95 mph (152.89 km/h)96.46 mph (155.24 km/h)
100 mph (160.93 km/h)101.54 mph (163.41 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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