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 305/100r20 Tire Comparison Side By Side
  365/80-20 305/100-20 Difference
Diameter inches (mm) 42.99 (1092) 44.02 (1118) 1.02 (26) 2.4%
Width inches (mm) 14.37 (365) 12.01 (305) -2.36 (-60) -16.4%
Circum. inches (mm) 135.06 (3430.62) 138.28 (3512.3) 3.22 (81.68) 2.4%
Sidewall Height inches (mm) 11.5 (292) 12.01 (305) 0.51 (13) 4.5%
Revolutions per mile (km) 469.11 (291.49) 458.2 (284.71) -10.91 (-6.78) -2.3%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.48 mph (32.95 km/h)
25 mph (40.23 km/h)25.6 mph (41.19 km/h)
30 mph (48.28 km/h)30.71 mph (49.43 km/h)
35 mph (56.33 km/h)35.83 mph (57.67 km/h)
40 mph (64.37 km/h)40.95 mph (65.91 km/h)
45 mph (72.42 km/h)46.07 mph (74.14 km/h)
50 mph (80.47 km/h)51.19 mph (82.38 km/h)
55 mph (88.51 km/h)56.31 mph (90.62 km/h)
60 mph (96.56 km/h)61.43 mph (98.86 km/h)
65 mph (104.61 km/h)66.55 mph (107.1 km/h)
70 mph (112.65 km/h)71.67 mph (115.34 km/h)
75 mph (120.7 km/h)76.79 mph (123.57 km/h)
80 mph (128.75 km/h)81.9 mph (131.81 km/h)
85 mph (136.79 km/h)87.02 mph (140.05 km/h)
90 mph (144.84 km/h)92.14 mph (148.29 km/h)
95 mph (152.89 km/h)97.26 mph (156.53 km/h)
100 mph (160.93 km/h)102.38 mph (164.77 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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