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 295/40r21 Tire Comparison Side By Side
  285/45-21 295/40-21 Difference
Diameter inches (mm) 31.1 (789.9) 30.29 (769.4) -0.81 (-20.5) -2.6%
Width inches (mm) 11.22 (285) 11.61 (295) 0.39 (10) 3.5%
Circum. inches (mm) 97.7 (2481.54) 95.16 (2417.14) -2.54 (-64.4) -2.6%
Sidewall Height inches (mm) 5.05 (128.25) 4.65 (118) -0.4 (-10.25) -8%
Revolutions per mile (km) 648.53 (402.97) 665.8 (413.71) 17.28 (10.74) 2.7%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.48 mph (31.35 km/h)
25 mph (40.23 km/h)24.35 mph (39.19 km/h)
30 mph (48.28 km/h)29.22 mph (47.03 km/h)
35 mph (56.33 km/h)34.09 mph (54.87 km/h)
40 mph (64.37 km/h)38.96 mph (62.7 km/h)
45 mph (72.42 km/h)43.83 mph (70.54 km/h)
50 mph (80.47 km/h)48.7 mph (78.38 km/h)
55 mph (88.51 km/h)53.57 mph (86.22 km/h)
60 mph (96.56 km/h)58.44 mph (94.05 km/h)
65 mph (104.61 km/h)63.31 mph (101.89 km/h)
70 mph (112.65 km/h)68.18 mph (109.73 km/h)
75 mph (120.7 km/h)73.05 mph (117.57 km/h)
80 mph (128.75 km/h)77.92 mph (125.41 km/h)
85 mph (136.79 km/h)82.79 mph (133.24 km/h)
90 mph (144.84 km/h)87.66 mph (141.08 km/h)
95 mph (152.89 km/h)92.53 mph (148.92 km/h)
100 mph (160.93 km/h)97.4 mph (156.76 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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