Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
180/55r18 vs 150/70r18 Tire Comparison Side By Side
  180/55-18 150/70-18 Difference
Diameter inches (mm) 25.8 (655.2) 26.27 (667.2) 0.47 (12) 1.8%
Width inches (mm) 7.09 (180) 5.91 (150) -1.18 (-30) -16.7%
Circum. inches (mm) 81.04 (2058.37) 82.52 (2096.07) 1.48 (37.7) 1.8%
Sidewall Height inches (mm) 3.9 (99) 4.13 (105) 0.24 (6) 6.1%
Revolutions per mile (km) 781.85 (485.82) 767.79 (477.08) -14.06 (-8.74) -1.8%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.37 mph (32.78 km/h)
25 mph (40.23 km/h)25.46 mph (40.97 km/h)
30 mph (48.28 km/h)30.55 mph (49.16 km/h)
35 mph (56.33 km/h)35.64 mph (57.36 km/h)
40 mph (64.37 km/h)40.73 mph (65.55 km/h)
45 mph (72.42 km/h)45.82 mph (73.75 km/h)
50 mph (80.47 km/h)50.92 mph (81.94 km/h)
55 mph (88.51 km/h)56.01 mph (90.14 km/h)
60 mph (96.56 km/h)61.1 mph (98.33 km/h)
65 mph (104.61 km/h)66.19 mph (106.52 km/h)
70 mph (112.65 km/h)71.28 mph (114.72 km/h)
75 mph (120.7 km/h)76.37 mph (122.91 km/h)
80 mph (128.75 km/h)81.47 mph (131.11 km/h)
85 mph (136.79 km/h)86.56 mph (139.3 km/h)
90 mph (144.84 km/h)91.65 mph (147.49 km/h)
95 mph (152.89 km/h)96.74 mph (155.69 km/h)
100 mph (160.93 km/h)101.83 mph (163.88 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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