Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
155/80r17 vs 245/40r18 Tire Comparison Side By Side
  155/80-17 245/40-18 Difference
Diameter inches (mm) 26.76 (679.8) 25.72 (653.2) -1.05 (-26.6) -3.9%
Width inches (mm) 6.1 (155) 9.65 (245) 3.54 (90) 58.1%
Circum. inches (mm) 84.08 (2135.65) 80.79 (2052.09) -3.29 (-83.57) -3.9%
Sidewall Height inches (mm) 4.88 (124) 3.86 (98) -1.02 (-26) -21%
Revolutions per mile (km) 753.56 (468.24) 784.25 (487.31) 30.69 (19.07) 4.1%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.22 mph (30.93 km/h)
25 mph (40.23 km/h)24.02 mph (38.66 km/h)
30 mph (48.28 km/h)28.83 mph (46.39 km/h)
35 mph (56.33 km/h)33.63 mph (54.12 km/h)
40 mph (64.37 km/h)38.43 mph (61.85 km/h)
45 mph (72.42 km/h)43.24 mph (69.59 km/h)
50 mph (80.47 km/h)48.04 mph (77.32 km/h)
55 mph (88.51 km/h)52.85 mph (85.05 km/h)
60 mph (96.56 km/h)57.65 mph (92.78 km/h)
65 mph (104.61 km/h)62.46 mph (100.51 km/h)
70 mph (112.65 km/h)67.26 mph (108.25 km/h)
75 mph (120.7 km/h)72.07 mph (115.98 km/h)
80 mph (128.75 km/h)76.87 mph (123.71 km/h)
85 mph (136.79 km/h)81.67 mph (131.44 km/h)
90 mph (144.84 km/h)86.48 mph (139.17 km/h)
95 mph (152.89 km/h)91.28 mph (146.91 km/h)
100 mph (160.93 km/h)96.09 mph (154.64 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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