Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
165/90r18 vs 255/50r20 Tire Comparison Side By Side
  165/90-18 255/50-20 Difference
Diameter inches (mm) 29.69 (754.2) 30.04 (763) 0.35 (8.8) 1.2%
Width inches (mm) 6.5 (165) 10.04 (255) 3.54 (90) 54.5%
Circum. inches (mm) 93.28 (2369.39) 94.37 (2397.04) 1.09 (27.65) 1.2%
Sidewall Height inches (mm) 5.85 (148.5) 5.02 (127.5) -0.83 (-21) -14.1%
Revolutions per mile (km) 679.22 (422.05) 671.39 (417.18) -7.83 (-4.87) -1.2%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.23 mph (32.56 km/h)
25 mph (40.23 km/h)25.29 mph (40.7 km/h)
30 mph (48.28 km/h)30.35 mph (48.84 km/h)
35 mph (56.33 km/h)35.41 mph (56.98 km/h)
40 mph (64.37 km/h)40.47 mph (65.12 km/h)
45 mph (72.42 km/h)45.53 mph (73.27 km/h)
50 mph (80.47 km/h)50.58 mph (81.41 km/h)
55 mph (88.51 km/h)55.64 mph (89.55 km/h)
60 mph (96.56 km/h)60.7 mph (97.69 km/h)
65 mph (104.61 km/h)65.76 mph (105.83 km/h)
70 mph (112.65 km/h)70.82 mph (113.97 km/h)
75 mph (120.7 km/h)75.88 mph (122.11 km/h)
80 mph (128.75 km/h)80.93 mph (130.25 km/h)
85 mph (136.79 km/h)85.99 mph (138.39 km/h)
90 mph (144.84 km/h)91.05 mph (146.53 km/h)
95 mph (152.89 km/h)96.11 mph (154.67 km/h)
100 mph (160.93 km/h)101.17 mph (162.81 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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