Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
285/35r21 vs 285/35r20 Tire Comparison Side By Side
  285/35-21 285/35-20 Difference
Diameter inches (mm) 28.85 (732.9) 27.85 (707.5) -1 (-25.4) -3.5%
Width inches (mm) 11.22 (285) 11.22 (285) 0 (0) 0%
Circum. inches (mm) 90.65 (2302.47) 87.51 (2222.68) -3.14 (-79.8) -3.5%
Sidewall Height inches (mm) 3.93 (99.75) 3.93 (99.75) 0 (0) 0%
Revolutions per mile (km) 698.96 (434.31) 724.06 (449.91) 25.09 (15.59) 3.6%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.31 mph (31.07 km/h)
25 mph (40.23 km/h)24.13 mph (38.84 km/h)
30 mph (48.28 km/h)28.96 mph (46.61 km/h)
35 mph (56.33 km/h)33.79 mph (54.38 km/h)
40 mph (64.37 km/h)38.61 mph (62.14 km/h)
45 mph (72.42 km/h)43.44 mph (69.91 km/h)
50 mph (80.47 km/h)48.27 mph (77.68 km/h)
55 mph (88.51 km/h)53.09 mph (85.45 km/h)
60 mph (96.56 km/h)57.92 mph (93.21 km/h)
65 mph (104.61 km/h)62.75 mph (100.98 km/h)
70 mph (112.65 km/h)67.57 mph (108.75 km/h)
75 mph (120.7 km/h)72.4 mph (116.52 km/h)
80 mph (128.75 km/h)77.23 mph (124.29 km/h)
85 mph (136.79 km/h)82.05 mph (132.05 km/h)
90 mph (144.84 km/h)86.88 mph (139.82 km/h)
95 mph (152.89 km/h)91.71 mph (147.59 km/h)
100 mph (160.93 km/h)96.53 mph (155.36 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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