Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
235/45r18 vs 225/45r18 Tire Comparison Side By Side
  235/45-18 225/45-18 Difference
Diameter inches (mm) 26.33 (668.7) 25.97 (659.7) -0.35 (-9) -1.3%
Width inches (mm) 9.25 (235) 8.86 (225) -0.39 (-10) -4.3%
Circum. inches (mm) 82.71 (2100.78) 81.59 (2072.51) -1.11 (-28.27) -1.3%
Sidewall Height inches (mm) 4.16 (105.75) 3.99 (101.25) -0.18 (-4.5) -4.3%
Revolutions per mile (km) 766.07 (476.01) 776.52 (482.51) 10.45 (6.49) 1.4%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.73 mph (31.75 km/h)
25 mph (40.23 km/h)24.66 mph (39.69 km/h)
30 mph (48.28 km/h)29.6 mph (47.63 km/h)
35 mph (56.33 km/h)34.53 mph (55.57 km/h)
40 mph (64.37 km/h)39.46 mph (63.51 km/h)
45 mph (72.42 km/h)44.39 mph (71.45 km/h)
50 mph (80.47 km/h)49.33 mph (79.38 km/h)
55 mph (88.51 km/h)54.26 mph (87.32 km/h)
60 mph (96.56 km/h)59.19 mph (95.26 km/h)
65 mph (104.61 km/h)64.13 mph (103.2 km/h)
70 mph (112.65 km/h)69.06 mph (111.14 km/h)
75 mph (120.7 km/h)73.99 mph (119.08 km/h)
80 mph (128.75 km/h)78.92 mph (127.01 km/h)
85 mph (136.79 km/h)83.86 mph (134.95 km/h)
90 mph (144.84 km/h)88.79 mph (142.89 km/h)
95 mph (152.89 km/h)93.72 mph (150.83 km/h)
100 mph (160.93 km/h)98.65 mph (158.77 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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