Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
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155/90r18 vs 135/80r18 Tire Comparison Side By Side
  155/90-18 135/80-18 Difference
Diameter inches (mm) 28.98 (736.2) 26.5 (673.2) -2.48 (-63) -8.6%
Width inches (mm) 6.1 (155) 5.31 (135) -0.79 (-20) -12.9%
Circum. inches (mm) 91.06 (2312.84) 83.26 (2114.92) -7.79 (-197.92) -8.6%
Sidewall Height inches (mm) 5.49 (139.5) 4.25 (108) -1.24 (-31.5) -22.6%
Revolutions per mile (km) 695.83 (432.37) 760.95 (472.83) 65.12 (40.46) 9.4%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)18.29 mph (29.43 km/h)
25 mph (40.23 km/h)22.86 mph (36.79 km/h)
30 mph (48.28 km/h)27.43 mph (44.15 km/h)
35 mph (56.33 km/h)32 mph (51.51 km/h)
40 mph (64.37 km/h)36.58 mph (58.87 km/h)
45 mph (72.42 km/h)41.15 mph (66.22 km/h)
50 mph (80.47 km/h)45.72 mph (73.58 km/h)
55 mph (88.51 km/h)50.29 mph (80.94 km/h)
60 mph (96.56 km/h)54.87 mph (88.3 km/h)
65 mph (104.61 km/h)59.44 mph (95.66 km/h)
70 mph (112.65 km/h)64.01 mph (103.01 km/h)
75 mph (120.7 km/h)68.58 mph (110.37 km/h)
80 mph (128.75 km/h)73.15 mph (117.73 km/h)
85 mph (136.79 km/h)77.73 mph (125.09 km/h)
90 mph (144.84 km/h)82.3 mph (132.45 km/h)
95 mph (152.89 km/h)86.87 mph (139.8 km/h)
100 mph (160.93 km/h)91.44 mph (147.16 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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