Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
155/65r15 vs 185/65r15 Tire Comparison Side By Side
  155/65-15 185/65-15 Difference
Diameter inches (mm) 22.93 (582.5) 24.47 (621.5) 1.54 (39) 6.7%
Width inches (mm) 6.1 (155) 7.28 (185) 1.18 (30) 19.4%
Circum. inches (mm) 72.05 (1829.98) 76.87 (1952.5) 4.82 (122.52) 6.7%
Sidewall Height inches (mm) 3.97 (100.75) 4.73 (120.25) 0.77 (19.5) 19.4%
Revolutions per mile (km) 879.43 (546.45) 824.25 (512.16) -55.19 (-34.29) -6.3%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)21.34 mph (34.34 km/h)
25 mph (40.23 km/h)26.67 mph (42.93 km/h)
30 mph (48.28 km/h)32.01 mph (51.51 km/h)
35 mph (56.33 km/h)37.34 mph (60.1 km/h)
40 mph (64.37 km/h)42.68 mph (68.68 km/h)
45 mph (72.42 km/h)48.01 mph (77.27 km/h)
50 mph (80.47 km/h)53.35 mph (85.85 km/h)
55 mph (88.51 km/h)58.68 mph (94.44 km/h)
60 mph (96.56 km/h)64.02 mph (103.03 km/h)
65 mph (104.61 km/h)69.35 mph (111.61 km/h)
70 mph (112.65 km/h)74.69 mph (120.2 km/h)
75 mph (120.7 km/h)80.02 mph (128.78 km/h)
80 mph (128.75 km/h)85.36 mph (137.37 km/h)
85 mph (136.79 km/h)90.69 mph (145.95 km/h)
90 mph (144.84 km/h)96.03 mph (154.54 km/h)
95 mph (152.89 km/h)101.36 mph (163.12 km/h)
100 mph (160.93 km/h)106.7 mph (171.71 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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