Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
365/80r20 vs 400/80r20 Tire Comparison Side By Side
  365/80-20 400/80-20 Difference
Diameter inches (mm) 42.99 (1092) 45.2 (1148) 2.2 (56) 5.1%
Width inches (mm) 14.37 (365) 15.75 (400) 1.38 (35) 9.6%
Circum. inches (mm) 135.06 (3430.62) 141.99 (3606.55) 6.93 (175.93) 5.1%
Sidewall Height inches (mm) 11.5 (292) 12.6 (320) 1.1 (28) 9.6%
Revolutions per mile (km) 469.11 (291.49) 446.23 (277.27) -22.88 (-14.22) -4.9%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)21.03 mph (33.84 km/h)
25 mph (40.23 km/h)26.28 mph (42.3 km/h)
30 mph (48.28 km/h)31.54 mph (50.76 km/h)
35 mph (56.33 km/h)36.79 mph (59.22 km/h)
40 mph (64.37 km/h)42.05 mph (67.68 km/h)
45 mph (72.42 km/h)47.31 mph (76.13 km/h)
50 mph (80.47 km/h)52.56 mph (84.59 km/h)
55 mph (88.51 km/h)57.82 mph (93.05 km/h)
60 mph (96.56 km/h)63.08 mph (101.51 km/h)
65 mph (104.61 km/h)68.33 mph (109.97 km/h)
70 mph (112.65 km/h)73.59 mph (118.43 km/h)
75 mph (120.7 km/h)78.85 mph (126.89 km/h)
80 mph (128.75 km/h)84.1 mph (135.35 km/h)
85 mph (136.79 km/h)89.36 mph (143.81 km/h)
90 mph (144.84 km/h)94.62 mph (152.27 km/h)
95 mph (152.89 km/h)99.87 mph (160.73 km/h)
100 mph (160.93 km/h)105.13 mph (169.19 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
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
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