Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
225/45r20 vs 245/45r20 Tire Comparison Side By Side
  225/45-20 245/45-20 Difference
Diameter inches (mm) 27.97 (710.5) 28.68 (728.5) 0.71 (18) 2.5%
Width inches (mm) 8.86 (225) 9.65 (245) 0.79 (20) 8.9%
Circum. inches (mm) 87.88 (2232.1) 90.1 (2288.65) 2.23 (56.55) 2.5%
Sidewall Height inches (mm) 3.99 (101.25) 4.34 (110.25) 0.35 (9) 8.9%
Revolutions per mile (km) 721 (448.01) 703.18 (436.94) -17.81 (-11.07) -2.5%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.51 mph (33 km/h)
25 mph (40.23 km/h)25.63 mph (41.25 km/h)
30 mph (48.28 km/h)30.76 mph (49.5 km/h)
35 mph (56.33 km/h)35.89 mph (57.75 km/h)
40 mph (64.37 km/h)41.01 mph (66 km/h)
45 mph (72.42 km/h)46.14 mph (74.26 km/h)
50 mph (80.47 km/h)51.27 mph (82.51 km/h)
55 mph (88.51 km/h)56.39 mph (90.76 km/h)
60 mph (96.56 km/h)61.52 mph (99.01 km/h)
65 mph (104.61 km/h)66.65 mph (107.26 km/h)
70 mph (112.65 km/h)71.77 mph (115.51 km/h)
75 mph (120.7 km/h)76.9 mph (123.76 km/h)
80 mph (128.75 km/h)82.03 mph (132.01 km/h)
85 mph (136.79 km/h)87.15 mph (140.26 km/h)
90 mph (144.84 km/h)92.28 mph (148.51 km/h)
95 mph (152.89 km/h)97.41 mph (156.76 km/h)
100 mph (160.93 km/h)102.53 mph (165.01 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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