Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
275/45r21 vs 275/55r20 Tire Comparison Side By Side
  275/45-21 275/55-20 Difference
Diameter inches (mm) 30.74 (780.9) 31.91 (810.5) 1.17 (29.6) 3.8%
Width inches (mm) 10.83 (275) 10.83 (275) 0 (0) 0%
Circum. inches (mm) 96.59 (2453.27) 100.25 (2546.26) 3.66 (92.99) 3.8%
Sidewall Height inches (mm) 4.87 (123.75) 5.95 (151.25) 1.08 (27.5) 22.2%
Revolutions per mile (km) 656 (407.62) 632.04 (392.73) -23.96 (-14.89) -3.7%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.76 mph (33.41 km/h)
25 mph (40.23 km/h)25.95 mph (41.76 km/h)
30 mph (48.28 km/h)31.14 mph (50.11 km/h)
35 mph (56.33 km/h)36.33 mph (58.46 km/h)
40 mph (64.37 km/h)41.52 mph (66.81 km/h)
45 mph (72.42 km/h)46.71 mph (75.17 km/h)
50 mph (80.47 km/h)51.9 mph (83.52 km/h)
55 mph (88.51 km/h)57.08 mph (91.87 km/h)
60 mph (96.56 km/h)62.27 mph (100.22 km/h)
65 mph (104.61 km/h)67.46 mph (108.57 km/h)
70 mph (112.65 km/h)72.65 mph (116.92 km/h)
75 mph (120.7 km/h)77.84 mph (125.28 km/h)
80 mph (128.75 km/h)83.03 mph (133.63 km/h)
85 mph (136.79 km/h)88.22 mph (141.98 km/h)
90 mph (144.84 km/h)93.41 mph (150.33 km/h)
95 mph (152.89 km/h)98.6 mph (158.68 km/h)
100 mph (160.93 km/h)103.79 mph (167.03 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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