Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
180/60r18 vs 245/60r18 Tire Comparison Side By Side
  180/60-18 245/60-18 Difference
Diameter inches (mm) 26.5 (673.2) 29.57 (751.2) 3.07 (78) 11.6%
Width inches (mm) 7.09 (180) 9.65 (245) 2.56 (65) 36.1%
Circum. inches (mm) 83.26 (2114.92) 92.91 (2359.96) 9.65 (245.04) 11.6%
Sidewall Height inches (mm) 4.25 (108) 5.79 (147) 1.54 (39) 36.1%
Revolutions per mile (km) 760.95 (472.83) 681.94 (423.73) -79.01 (-49.1) -10.4%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)22.32 mph (35.92 km/h)
25 mph (40.23 km/h)27.9 mph (44.9 km/h)
30 mph (48.28 km/h)33.48 mph (53.87 km/h)
35 mph (56.33 km/h)39.06 mph (62.85 km/h)
40 mph (64.37 km/h)44.63 mph (71.83 km/h)
45 mph (72.42 km/h)50.21 mph (80.81 km/h)
50 mph (80.47 km/h)55.79 mph (89.79 km/h)
55 mph (88.51 km/h)61.37 mph (98.77 km/h)
60 mph (96.56 km/h)66.95 mph (107.75 km/h)
65 mph (104.61 km/h)72.53 mph (116.73 km/h)
70 mph (112.65 km/h)78.11 mph (125.71 km/h)
75 mph (120.7 km/h)83.69 mph (134.69 km/h)
80 mph (128.75 km/h)89.27 mph (143.67 km/h)
85 mph (136.79 km/h)94.85 mph (152.64 km/h)
90 mph (144.84 km/h)100.43 mph (161.62 km/h)
95 mph (152.89 km/h)106.01 mph (170.6 km/h)
100 mph (160.93 km/h)111.59 mph (179.58 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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