Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
285/30r21 vs 245/35r21 Tire Comparison Side By Side
  285/30-21 245/35-21 Difference
Diameter inches (mm) 27.73 (704.4) 27.75 (704.9) 0.02 (0.5) 0.1%
Width inches (mm) 11.22 (285) 9.65 (245) -1.57 (-40) -14%
Circum. inches (mm) 87.12 (2212.94) 87.19 (2214.51) 0.06 (1.57) 0.1%
Sidewall Height inches (mm) 3.37 (85.5) 3.38 (85.75) 0.01 (0.25) 0.3%
Revolutions per mile (km) 727.24 (451.89) 726.73 (451.57) -0.52 (-0.32) -0.1%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.01 mph (32.21 km/h)
25 mph (40.23 km/h)25.02 mph (40.26 km/h)
30 mph (48.28 km/h)30.02 mph (48.31 km/h)
35 mph (56.33 km/h)35.02 mph (56.37 km/h)
40 mph (64.37 km/h)40.03 mph (64.42 km/h)
45 mph (72.42 km/h)45.03 mph (72.47 km/h)
50 mph (80.47 km/h)50.04 mph (80.52 km/h)
55 mph (88.51 km/h)55.04 mph (88.58 km/h)
60 mph (96.56 km/h)60.04 mph (96.63 km/h)
65 mph (104.61 km/h)65.05 mph (104.68 km/h)
70 mph (112.65 km/h)70.05 mph (112.73 km/h)
75 mph (120.7 km/h)75.05 mph (120.79 km/h)
80 mph (128.75 km/h)80.06 mph (128.84 km/h)
85 mph (136.79 km/h)85.06 mph (136.89 km/h)
90 mph (144.84 km/h)90.06 mph (144.94 km/h)
95 mph (152.89 km/h)95.07 mph (153 km/h)
100 mph (160.93 km/h)100.07 mph (161.05 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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