Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
215/40r18 vs 225/40r18 Tire Comparison Side By Side
  215/40-18 225/40-18 Difference
Diameter inches (mm) 24.77 (629.2) 25.09 (637.2) 0.31 (8) 1.3%
Width inches (mm) 8.46 (215) 8.86 (225) 0.39 (10) 4.7%
Circum. inches (mm) 77.82 (1976.69) 78.81 (2001.82) 0.99 (25.13) 1.3%
Sidewall Height inches (mm) 3.39 (86) 3.54 (90) 0.16 (4) 4.7%
Revolutions per mile (km) 814.16 (505.9) 803.94 (499.54) -10.22 (-6.35) -1.3%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.25 mph (32.6 km/h)
25 mph (40.23 km/h)25.32 mph (40.75 km/h)
30 mph (48.28 km/h)30.38 mph (48.89 km/h)
35 mph (56.33 km/h)35.45 mph (57.04 km/h)
40 mph (64.37 km/h)40.51 mph (65.19 km/h)
45 mph (72.42 km/h)45.57 mph (73.34 km/h)
50 mph (80.47 km/h)50.64 mph (81.49 km/h)
55 mph (88.51 km/h)55.7 mph (89.64 km/h)
60 mph (96.56 km/h)60.76 mph (97.79 km/h)
65 mph (104.61 km/h)65.83 mph (105.94 km/h)
70 mph (112.65 km/h)70.89 mph (114.09 km/h)
75 mph (120.7 km/h)75.95 mph (122.24 km/h)
80 mph (128.75 km/h)81.02 mph (130.38 km/h)
85 mph (136.79 km/h)86.08 mph (138.53 km/h)
90 mph (144.84 km/h)91.14 mph (146.68 km/h)
95 mph (152.89 km/h)96.21 mph (154.83 km/h)
100 mph (160.93 km/h)101.27 mph (162.98 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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