Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
155/70r18 vs 225/65r18 Tire Comparison Side By Side
  155/70-18 225/65-18 Difference
Diameter inches (mm) 26.54 (674.2) 29.52 (749.7) 2.97 (75.5) 11.2%
Width inches (mm) 6.1 (155) 8.86 (225) 2.76 (70) 45.2%
Circum. inches (mm) 83.39 (2118.06) 92.73 (2355.25) 9.34 (237.19) 11.2%
Sidewall Height inches (mm) 4.27 (108.5) 5.76 (146.25) 1.49 (37.75) 34.8%
Revolutions per mile (km) 759.82 (472.13) 683.3 (424.58) -76.52 (-47.55) -10.1%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)22.24 mph (35.79 km/h)
25 mph (40.23 km/h)27.8 mph (44.74 km/h)
30 mph (48.28 km/h)33.36 mph (53.69 km/h)
35 mph (56.33 km/h)38.92 mph (62.63 km/h)
40 mph (64.37 km/h)44.48 mph (71.58 km/h)
45 mph (72.42 km/h)50.04 mph (80.53 km/h)
50 mph (80.47 km/h)55.6 mph (89.48 km/h)
55 mph (88.51 km/h)61.16 mph (98.43 km/h)
60 mph (96.56 km/h)66.72 mph (107.37 km/h)
65 mph (104.61 km/h)72.28 mph (116.32 km/h)
70 mph (112.65 km/h)77.84 mph (125.27 km/h)
75 mph (120.7 km/h)83.4 mph (134.22 km/h)
80 mph (128.75 km/h)88.96 mph (143.17 km/h)
85 mph (136.79 km/h)94.52 mph (152.11 km/h)
90 mph (144.84 km/h)100.08 mph (161.06 km/h)
95 mph (152.89 km/h)105.64 mph (170.01 km/h)
100 mph (160.93 km/h)111.2 mph (178.96 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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