Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
285/40r20 vs 255/45r20 Tire Comparison Side By Side
  285/40-20 255/45-20 Difference
Diameter inches (mm) 28.98 (736) 29.04 (737.5) 0.06 (1.5) 0.2%
Width inches (mm) 11.22 (285) 10.04 (255) -1.18 (-30) -10.5%
Circum. inches (mm) 91.03 (2312.21) 91.22 (2316.92) 0.19 (4.71) 0.2%
Sidewall Height inches (mm) 4.49 (114) 4.52 (114.75) 0.03 (0.75) 0.7%
Revolutions per mile (km) 696.02 (432.49) 694.6 (431.61) -1.42 (-0.88) -0.2%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.04 mph (32.25 km/h)
25 mph (40.23 km/h)25.05 mph (40.32 km/h)
30 mph (48.28 km/h)30.06 mph (48.38 km/h)
35 mph (56.33 km/h)35.07 mph (56.44 km/h)
40 mph (64.37 km/h)40.08 mph (64.51 km/h)
45 mph (72.42 km/h)45.09 mph (72.57 km/h)
50 mph (80.47 km/h)50.1 mph (80.63 km/h)
55 mph (88.51 km/h)55.11 mph (88.69 km/h)
60 mph (96.56 km/h)60.12 mph (96.76 km/h)
65 mph (104.61 km/h)65.13 mph (104.82 km/h)
70 mph (112.65 km/h)70.14 mph (112.88 km/h)
75 mph (120.7 km/h)75.15 mph (120.95 km/h)
80 mph (128.75 km/h)80.16 mph (129.01 km/h)
85 mph (136.79 km/h)85.17 mph (137.07 km/h)
90 mph (144.84 km/h)90.18 mph (145.14 km/h)
95 mph (152.89 km/h)95.19 mph (153.2 km/h)
100 mph (160.93 km/h)100.2 mph (161.26 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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