Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
305/25r20 vs 285/35r18 Tire Comparison Side By Side
  305/25-20 285/35-18 Difference
Diameter inches (mm) 26 (660.5) 25.85 (656.7) -0.15 (-3.8) -0.6%
Width inches (mm) 12.01 (305) 11.22 (285) -0.79 (-20) -6.6%
Circum. inches (mm) 81.69 (2075.02) 81.22 (2063.08) -0.47 (-11.94) -0.6%
Sidewall Height inches (mm) 3 (76.25) 3.93 (99.75) 0.93 (23.5) 30.8%
Revolutions per mile (km) 775.58 (481.92) 780.07 (484.71) 4.49 (2.79) 0.6%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.88 mph (32 km/h)
25 mph (40.23 km/h)24.86 mph (40 km/h)
30 mph (48.28 km/h)29.83 mph (48 km/h)
35 mph (56.33 km/h)34.8 mph (56 km/h)
40 mph (64.37 km/h)39.77 mph (64 km/h)
45 mph (72.42 km/h)44.74 mph (72 km/h)
50 mph (80.47 km/h)49.71 mph (80 km/h)
55 mph (88.51 km/h)54.68 mph (88 km/h)
60 mph (96.56 km/h)59.65 mph (96.01 km/h)
65 mph (104.61 km/h)64.63 mph (104.01 km/h)
70 mph (112.65 km/h)69.6 mph (112.01 km/h)
75 mph (120.7 km/h)74.57 mph (120.01 km/h)
80 mph (128.75 km/h)79.54 mph (128.01 km/h)
85 mph (136.79 km/h)84.51 mph (136.01 km/h)
90 mph (144.84 km/h)89.48 mph (144.01 km/h)
95 mph (152.89 km/h)94.45 mph (152.01 km/h)
100 mph (160.93 km/h)99.42 mph (160.01 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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