Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
185/65r13 vs 185/65r15 Tire Comparison Side By Side
  185/65-13 185/65-15 Difference
Diameter inches (mm) 22.47 (570.7) 24.47 (621.5) 2 (50.8) 8.9%
Width inches (mm) 7.28 (185) 7.28 (185) 0 (0) 0%
Circum. inches (mm) 70.59 (1792.91) 76.87 (1952.5) 6.28 (159.59) 8.9%
Sidewall Height inches (mm) 4.73 (120.25) 4.73 (120.25) 0 (0) 0%
Revolutions per mile (km) 897.62 (557.75) 824.25 (512.16) -73.37 (-45.59) -8.2%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)21.78 mph (35.05 km/h)
25 mph (40.23 km/h)27.23 mph (43.82 km/h)
30 mph (48.28 km/h)32.67 mph (52.58 km/h)
35 mph (56.33 km/h)38.12 mph (61.34 km/h)
40 mph (64.37 km/h)43.56 mph (70.1 km/h)
45 mph (72.42 km/h)49.01 mph (78.87 km/h)
50 mph (80.47 km/h)54.45 mph (87.63 km/h)
55 mph (88.51 km/h)59.9 mph (96.39 km/h)
60 mph (96.56 km/h)65.34 mph (105.16 km/h)
65 mph (104.61 km/h)70.79 mph (113.92 km/h)
70 mph (112.65 km/h)76.23 mph (122.68 km/h)
75 mph (120.7 km/h)81.68 mph (131.45 km/h)
80 mph (128.75 km/h)87.12 mph (140.21 km/h)
85 mph (136.79 km/h)92.57 mph (148.97 km/h)
90 mph (144.84 km/h)98.01 mph (157.73 km/h)
95 mph (152.89 km/h)103.46 mph (166.5 km/h)
100 mph (160.93 km/h)108.9 mph (175.26 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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