Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
255/45r20 vs 235/60r18 Tire Comparison Side By Side
  255/45-20 235/60-18 Difference
Diameter inches (mm) 29.04 (737.5) 29.1 (739.2) 0.07 (1.7) 0.2%
Width inches (mm) 10.04 (255) 9.25 (235) -0.79 (-20) -7.8%
Circum. inches (mm) 91.22 (2316.92) 91.43 (2322.27) 0.21 (5.34) 0.2%
Sidewall Height inches (mm) 4.52 (114.75) 5.55 (141) 1.03 (26.25) 22.9%
Revolutions per mile (km) 694.6 (431.61) 693.01 (430.61) -1.6 (-0.99) -0.2%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.05 mph (32.26 km/h)
25 mph (40.23 km/h)25.06 mph (40.33 km/h)
30 mph (48.28 km/h)30.07 mph (48.39 km/h)
35 mph (56.33 km/h)35.08 mph (56.46 km/h)
40 mph (64.37 km/h)40.09 mph (64.52 km/h)
45 mph (72.42 km/h)45.1 mph (72.59 km/h)
50 mph (80.47 km/h)50.12 mph (80.65 km/h)
55 mph (88.51 km/h)55.13 mph (88.72 km/h)
60 mph (96.56 km/h)60.14 mph (96.78 km/h)
65 mph (104.61 km/h)65.15 mph (104.85 km/h)
70 mph (112.65 km/h)70.16 mph (112.91 km/h)
75 mph (120.7 km/h)75.17 mph (120.98 km/h)
80 mph (128.75 km/h)80.18 mph (129.04 km/h)
85 mph (136.79 km/h)85.2 mph (137.11 km/h)
90 mph (144.84 km/h)90.21 mph (145.18 km/h)
95 mph (152.89 km/h)95.22 mph (153.24 km/h)
100 mph (160.93 km/h)100.23 mph (161.31 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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