Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
255/55r20 vs 275/45r21 Tire Comparison Side By Side
  255/55-20 275/45-21 Difference
Diameter inches (mm) 31.04 (788.5) 30.74 (780.9) -0.3 (-7.6) -1%
Width inches (mm) 10.04 (255) 10.83 (275) 0.79 (20) 7.8%
Circum. inches (mm) 97.53 (2477.15) 96.59 (2453.27) -0.94 (-23.88) -1%
Sidewall Height inches (mm) 5.52 (140.25) 4.87 (123.75) -0.65 (-16.5) -11.8%
Revolutions per mile (km) 649.68 (403.69) 656 (407.62) 6.32 (3.93) 1%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.81 mph (31.88 km/h)
25 mph (40.23 km/h)24.76 mph (39.85 km/h)
30 mph (48.28 km/h)29.71 mph (47.82 km/h)
35 mph (56.33 km/h)34.66 mph (55.78 km/h)
40 mph (64.37 km/h)39.61 mph (63.75 km/h)
45 mph (72.42 km/h)44.57 mph (71.72 km/h)
50 mph (80.47 km/h)49.52 mph (79.69 km/h)
55 mph (88.51 km/h)54.47 mph (87.66 km/h)
60 mph (96.56 km/h)59.42 mph (95.63 km/h)
65 mph (104.61 km/h)64.37 mph (103.6 km/h)
70 mph (112.65 km/h)69.33 mph (111.57 km/h)
75 mph (120.7 km/h)74.28 mph (119.54 km/h)
80 mph (128.75 km/h)79.23 mph (127.51 km/h)
85 mph (136.79 km/h)84.18 mph (135.48 km/h)
90 mph (144.84 km/h)89.13 mph (143.45 km/h)
95 mph (152.89 km/h)94.08 mph (151.41 km/h)
100 mph (160.93 km/h)99.04 mph (159.38 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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