Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
125/70r18 vs 225/40r18 Tire Comparison Side By Side
  125/70-18 225/40-18 Difference
Diameter inches (mm) 24.89 (632.2) 25.09 (637.2) 0.2 (5) 0.8%
Width inches (mm) 4.92 (125) 8.86 (225) 3.94 (100) 80%
Circum. inches (mm) 78.19 (1986.11) 78.81 (2001.82) 0.62 (15.71) 0.8%
Sidewall Height inches (mm) 3.44 (87.5) 3.54 (90) 0.1 (2.5) 2.9%
Revolutions per mile (km) 810.3 (503.49) 803.94 (499.54) -6.36 (-3.95) -0.8%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.16 mph (32.44 km/h)
25 mph (40.23 km/h)25.2 mph (40.55 km/h)
30 mph (48.28 km/h)30.24 mph (48.66 km/h)
35 mph (56.33 km/h)35.28 mph (56.77 km/h)
40 mph (64.37 km/h)40.32 mph (64.88 km/h)
45 mph (72.42 km/h)45.36 mph (72.99 km/h)
50 mph (80.47 km/h)50.4 mph (81.1 km/h)
55 mph (88.51 km/h)55.43 mph (89.21 km/h)
60 mph (96.56 km/h)60.47 mph (97.32 km/h)
65 mph (104.61 km/h)65.51 mph (105.43 km/h)
70 mph (112.65 km/h)70.55 mph (113.55 km/h)
75 mph (120.7 km/h)75.59 mph (121.66 km/h)
80 mph (128.75 km/h)80.63 mph (129.77 km/h)
85 mph (136.79 km/h)85.67 mph (137.88 km/h)
90 mph (144.84 km/h)90.71 mph (145.99 km/h)
95 mph (152.89 km/h)95.75 mph (154.1 km/h)
100 mph (160.93 km/h)100.79 mph (162.21 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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