Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
305/55r20 vs 35/12.5r20 Tire Comparison Side By Side
  305/55-20 35/12.5-20 Difference
Diameter inches (mm) 33.21 (843.5) 35.02 (889.6) 1.81 (46.1) 5.5%
Width inches (mm) 12.01 (305) 12.52 (318) 0.51 (13) 4.3%
Circum. inches (mm) 104.33 (2649.93) 110.03 (2794.76) 5.7 (144.83) 5.5%
Sidewall Height inches (mm) 6.6 (167.75) 7.51 (190.8) 0.91 (23.05) 13.7%
Revolutions per mile (km) 607.31 (377.37) 575.84 (357.81) -31.47 (-19.56) -5.2%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)21.09 mph (33.95 km/h)
25 mph (40.23 km/h)26.37 mph (42.43 km/h)
30 mph (48.28 km/h)31.64 mph (50.92 km/h)
35 mph (56.33 km/h)36.91 mph (59.41 km/h)
40 mph (64.37 km/h)42.19 mph (67.89 km/h)
45 mph (72.42 km/h)47.46 mph (76.38 km/h)
50 mph (80.47 km/h)52.73 mph (84.87 km/h)
55 mph (88.51 km/h)58.01 mph (93.35 km/h)
60 mph (96.56 km/h)63.28 mph (101.84 km/h)
65 mph (104.61 km/h)68.55 mph (110.32 km/h)
70 mph (112.65 km/h)73.83 mph (118.81 km/h)
75 mph (120.7 km/h)79.1 mph (127.3 km/h)
80 mph (128.75 km/h)84.37 mph (135.78 km/h)
85 mph (136.79 km/h)89.65 mph (144.27 km/h)
90 mph (144.84 km/h)94.92 mph (152.76 km/h)
95 mph (152.89 km/h)100.19 mph (161.24 km/h)
100 mph (160.93 km/h)105.47 mph (169.73 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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