Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
255/50r20 vs 275/45r21 Tire Comparison Side By Side
  255/50-20 275/45-21 Difference
Diameter inches (mm) 30.04 (763) 30.74 (780.9) 0.7 (17.9) 2.3%
Width inches (mm) 10.04 (255) 10.83 (275) 0.79 (20) 7.8%
Circum. inches (mm) 94.37 (2397.04) 96.59 (2453.27) 2.21 (56.23) 2.3%
Sidewall Height inches (mm) 5.02 (127.5) 4.87 (123.75) -0.15 (-3.75) -2.9%
Revolutions per mile (km) 671.39 (417.18) 656 (407.62) -15.39 (-9.56) -2.3%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.47 mph (32.94 km/h)
25 mph (40.23 km/h)25.59 mph (41.18 km/h)
30 mph (48.28 km/h)30.7 mph (49.41 km/h)
35 mph (56.33 km/h)35.82 mph (57.65 km/h)
40 mph (64.37 km/h)40.94 mph (65.88 km/h)
45 mph (72.42 km/h)46.06 mph (74.12 km/h)
50 mph (80.47 km/h)51.17 mph (82.36 km/h)
55 mph (88.51 km/h)56.29 mph (90.59 km/h)
60 mph (96.56 km/h)61.41 mph (98.83 km/h)
65 mph (104.61 km/h)66.52 mph (107.06 km/h)
70 mph (112.65 km/h)71.64 mph (115.3 km/h)
75 mph (120.7 km/h)76.76 mph (123.53 km/h)
80 mph (128.75 km/h)81.88 mph (131.77 km/h)
85 mph (136.79 km/h)86.99 mph (140 km/h)
90 mph (144.84 km/h)92.11 mph (148.24 km/h)
95 mph (152.89 km/h)97.23 mph (156.47 km/h)
100 mph (160.93 km/h)102.35 mph (164.71 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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