Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
235/45r20 vs 235/75r15 Tire Comparison Side By Side
  235/45-20 235/75-15 Difference
Diameter inches (mm) 28.33 (719.5) 28.88 (733.5) 0.55 (14) 1.9%
Width inches (mm) 9.25 (235) 9.25 (235) 0 (0) 0%
Circum. inches (mm) 88.99 (2260.38) 90.72 (2304.36) 1.73 (43.98) 1.9%
Sidewall Height inches (mm) 4.16 (105.75) 6.94 (176.25) 2.78 (70.5) 66.7%
Revolutions per mile (km) 711.98 (442.4) 698.39 (433.96) -13.59 (-8.44) -1.9%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.39 mph (32.81 km/h)
25 mph (40.23 km/h)25.49 mph (41.02 km/h)
30 mph (48.28 km/h)30.58 mph (49.22 km/h)
35 mph (56.33 km/h)35.68 mph (57.42 km/h)
40 mph (64.37 km/h)40.78 mph (65.63 km/h)
45 mph (72.42 km/h)45.88 mph (73.83 km/h)
50 mph (80.47 km/h)50.97 mph (82.03 km/h)
55 mph (88.51 km/h)56.07 mph (90.24 km/h)
60 mph (96.56 km/h)61.17 mph (98.44 km/h)
65 mph (104.61 km/h)66.26 mph (106.64 km/h)
70 mph (112.65 km/h)71.36 mph (114.85 km/h)
75 mph (120.7 km/h)76.46 mph (123.05 km/h)
80 mph (128.75 km/h)81.56 mph (131.25 km/h)
85 mph (136.79 km/h)86.65 mph (139.46 km/h)
90 mph (144.84 km/h)91.75 mph (147.66 km/h)
95 mph (152.89 km/h)96.85 mph (155.86 km/h)
100 mph (160.93 km/h)101.95 mph (164.07 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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