Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
155/70r18 vs 255/55r18 Tire Comparison Side By Side
  155/70-18 255/55-18 Difference
Diameter inches (mm) 26.54 (674.2) 29.04 (737.7) 2.5 (63.5) 9.4%
Width inches (mm) 6.1 (155) 10.04 (255) 3.94 (100) 64.5%
Circum. inches (mm) 83.39 (2118.06) 91.24 (2317.55) 7.85 (199.49) 9.4%
Sidewall Height inches (mm) 4.27 (108.5) 5.52 (140.25) 1.25 (31.75) 29.3%
Revolutions per mile (km) 759.82 (472.13) 694.42 (431.49) -65.4 (-40.64) -8.6%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)21.88 mph (35.22 km/h)
25 mph (40.23 km/h)27.35 mph (44.02 km/h)
30 mph (48.28 km/h)32.83 mph (52.83 km/h)
35 mph (56.33 km/h)38.3 mph (61.63 km/h)
40 mph (64.37 km/h)43.77 mph (70.44 km/h)
45 mph (72.42 km/h)49.24 mph (79.24 km/h)
50 mph (80.47 km/h)54.71 mph (88.05 km/h)
55 mph (88.51 km/h)60.18 mph (96.85 km/h)
60 mph (96.56 km/h)65.65 mph (105.66 km/h)
65 mph (104.61 km/h)71.12 mph (114.46 km/h)
70 mph (112.65 km/h)76.59 mph (123.26 km/h)
75 mph (120.7 km/h)82.06 mph (132.07 km/h)
80 mph (128.75 km/h)87.53 mph (140.87 km/h)
85 mph (136.79 km/h)93.01 mph (149.68 km/h)
90 mph (144.84 km/h)98.48 mph (158.48 km/h)
95 mph (152.89 km/h)103.95 mph (167.29 km/h)
100 mph (160.93 km/h)109.42 mph (176.09 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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