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 190/55r18 Tire Comparison Side By Side
  180/55-18 190/55-18 Difference
Diameter inches (mm) 25.8 (655.2) 26.23 (666.2) 0.43 (11) 1.7%
Width inches (mm) 7.09 (180) 7.48 (190) 0.39 (10) 5.6%
Circum. inches (mm) 81.04 (2058.37) 82.4 (2092.93) 1.36 (34.56) 1.7%
Sidewall Height inches (mm) 3.9 (99) 4.11 (104.5) 0.22 (5.5) 5.6%
Revolutions per mile (km) 781.85 (485.82) 768.94 (477.8) -12.91 (-8.02) -1.7%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.34 mph (32.73 km/h)
25 mph (40.23 km/h)25.42 mph (40.91 km/h)
30 mph (48.28 km/h)30.5 mph (49.09 km/h)
35 mph (56.33 km/h)35.59 mph (57.27 km/h)
40 mph (64.37 km/h)40.67 mph (65.45 km/h)
45 mph (72.42 km/h)45.76 mph (73.64 km/h)
50 mph (80.47 km/h)50.84 mph (81.82 km/h)
55 mph (88.51 km/h)55.92 mph (90 km/h)
60 mph (96.56 km/h)61.01 mph (98.18 km/h)
65 mph (104.61 km/h)66.09 mph (106.36 km/h)
70 mph (112.65 km/h)71.18 mph (114.55 km/h)
75 mph (120.7 km/h)76.26 mph (122.73 km/h)
80 mph (128.75 km/h)81.34 mph (130.91 km/h)
85 mph (136.79 km/h)86.43 mph (139.09 km/h)
90 mph (144.84 km/h)91.51 mph (147.27 km/h)
95 mph (152.89 km/h)96.59 mph (155.45 km/h)
100 mph (160.93 km/h)101.68 mph (163.64 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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