Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
285/45r21 vs 265/45r21 Tire Comparison Side By Side
  285/45-21 265/45-21 Difference
Diameter inches (mm) 31.1 (789.9) 30.39 (771.9) -0.71 (-18) -2.3%
Width inches (mm) 11.22 (285) 10.43 (265) -0.79 (-20) -7%
Circum. inches (mm) 97.7 (2481.54) 95.47 (2425) -2.23 (-56.55) -2.3%
Sidewall Height inches (mm) 5.05 (128.25) 4.69 (119.25) -0.35 (-9) -7%
Revolutions per mile (km) 648.53 (402.97) 663.65 (412.37) 15.12 (9.4) 2.3%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.54 mph (31.45 km/h)
25 mph (40.23 km/h)24.43 mph (39.32 km/h)
30 mph (48.28 km/h)29.32 mph (47.18 km/h)
35 mph (56.33 km/h)34.2 mph (55.04 km/h)
40 mph (64.37 km/h)39.09 mph (62.91 km/h)
45 mph (72.42 km/h)43.97 mph (70.77 km/h)
50 mph (80.47 km/h)48.86 mph (78.63 km/h)
55 mph (88.51 km/h)53.75 mph (86.5 km/h)
60 mph (96.56 km/h)58.63 mph (94.36 km/h)
65 mph (104.61 km/h)63.52 mph (102.22 km/h)
70 mph (112.65 km/h)68.4 mph (110.09 km/h)
75 mph (120.7 km/h)73.29 mph (117.95 km/h)
80 mph (128.75 km/h)78.18 mph (125.81 km/h)
85 mph (136.79 km/h)83.06 mph (133.68 km/h)
90 mph (144.84 km/h)87.95 mph (141.54 km/h)
95 mph (152.89 km/h)92.84 mph (149.4 km/h)
100 mph (160.93 km/h)97.72 mph (157.27 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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