Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
185/75r15 vs 185/70r15 Tire Comparison Side By Side
  185/75-15 185/70-15 Difference
Diameter inches (mm) 25.93 (658.5) 25.2 (640) -0.73 (-18.5) -2.8%
Width inches (mm) 7.28 (185) 7.28 (185) 0 (0) 0%
Circum. inches (mm) 81.45 (2068.74) 79.16 (2010.62) -2.29 (-58.12) -2.8%
Sidewall Height inches (mm) 5.46 (138.75) 5.1 (129.5) -0.36 (-9.25) -6.7%
Revolutions per mile (km) 777.93 (483.39) 800.42 (497.36) 22.49 (13.97) 2.9%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.44 mph (31.28 km/h)
25 mph (40.23 km/h)24.3 mph (39.1 km/h)
30 mph (48.28 km/h)29.16 mph (46.92 km/h)
35 mph (56.33 km/h)34.02 mph (54.74 km/h)
40 mph (64.37 km/h)38.88 mph (62.57 km/h)
45 mph (72.42 km/h)43.74 mph (70.39 km/h)
50 mph (80.47 km/h)48.6 mph (78.21 km/h)
55 mph (88.51 km/h)53.45 mph (86.03 km/h)
60 mph (96.56 km/h)58.31 mph (93.85 km/h)
65 mph (104.61 km/h)63.17 mph (101.67 km/h)
70 mph (112.65 km/h)68.03 mph (109.49 km/h)
75 mph (120.7 km/h)72.89 mph (117.31 km/h)
80 mph (128.75 km/h)77.75 mph (125.13 km/h)
85 mph (136.79 km/h)82.61 mph (132.95 km/h)
90 mph (144.84 km/h)87.47 mph (140.77 km/h)
95 mph (152.89 km/h)92.33 mph (148.59 km/h)
100 mph (160.93 km/h)97.19 mph (156.41 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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