Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
225/30r20 vs 255/30r20 Tire Comparison Side By Side
  225/30-20 255/30-20 Difference
Diameter inches (mm) 25.31 (643) 26.02 (661) 0.71 (18) 2.8%
Width inches (mm) 8.86 (225) 10.04 (255) 1.18 (30) 13.3%
Circum. inches (mm) 79.53 (2020.04) 81.76 (2076.59) 2.23 (56.55) 2.8%
Sidewall Height inches (mm) 2.66 (67.5) 3.01 (76.5) 0.35 (9) 13.3%
Revolutions per mile (km) 796.69 (495.04) 774.99 (481.56) -21.69 (-13.48) -2.7%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.56 mph (33.09 km/h)
25 mph (40.23 km/h)25.7 mph (41.36 km/h)
30 mph (48.28 km/h)30.84 mph (49.63 km/h)
35 mph (56.33 km/h)35.98 mph (57.9 km/h)
40 mph (64.37 km/h)41.12 mph (66.18 km/h)
45 mph (72.42 km/h)46.26 mph (74.45 km/h)
50 mph (80.47 km/h)51.4 mph (82.72 km/h)
55 mph (88.51 km/h)56.54 mph (90.99 km/h)
60 mph (96.56 km/h)61.68 mph (99.26 km/h)
65 mph (104.61 km/h)66.82 mph (107.54 km/h)
70 mph (112.65 km/h)71.96 mph (115.81 km/h)
75 mph (120.7 km/h)77.1 mph (124.08 km/h)
80 mph (128.75 km/h)82.24 mph (132.35 km/h)
85 mph (136.79 km/h)87.38 mph (140.62 km/h)
90 mph (144.84 km/h)92.52 mph (148.9 km/h)
95 mph (152.89 km/h)97.66 mph (157.17 km/h)
100 mph (160.93 km/h)102.8 mph (165.44 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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