Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
185/50r17 vs 185/40r17 Tire Comparison Side By Side
  185/50-17 185/40-17 Difference
Diameter inches (mm) 24.28 (616.8) 22.83 (579.8) -1.46 (-37) -6%
Width inches (mm) 7.28 (185) 7.28 (185) 0 (0) 0%
Circum. inches (mm) 76.29 (1937.73) 71.71 (1821.5) -4.58 (-116.24) -6%
Sidewall Height inches (mm) 3.64 (92.5) 2.91 (74) -0.73 (-18.5) -20%
Revolutions per mile (km) 830.53 (516.07) 883.53 (549) 53 (32.93) 6.4%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)18.8 mph (30.26 km/h)
25 mph (40.23 km/h)23.5 mph (37.82 km/h)
30 mph (48.28 km/h)28.2 mph (45.38 km/h)
35 mph (56.33 km/h)32.9 mph (52.95 km/h)
40 mph (64.37 km/h)37.6 mph (60.51 km/h)
45 mph (72.42 km/h)42.3 mph (68.08 km/h)
50 mph (80.47 km/h)47 mph (75.64 km/h)
55 mph (88.51 km/h)51.7 mph (83.2 km/h)
60 mph (96.56 km/h)56.4 mph (90.77 km/h)
65 mph (104.61 km/h)61.1 mph (98.33 km/h)
70 mph (112.65 km/h)65.8 mph (105.9 km/h)
75 mph (120.7 km/h)70.5 mph (113.46 km/h)
80 mph (128.75 km/h)75.2 mph (121.02 km/h)
85 mph (136.79 km/h)79.9 mph (128.59 km/h)
90 mph (144.84 km/h)84.6 mph (136.15 km/h)
95 mph (152.89 km/h)89.3 mph (143.72 km/h)
100 mph (160.93 km/h)94 mph (151.28 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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