Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
175/55r17 vs 185/65r15 Tire Comparison Side By Side
  175/55-17 185/65-15 Difference
Diameter inches (mm) 24.58 (624.3) 24.47 (621.5) -0.11 (-2.8) -0.4%
Width inches (mm) 6.89 (175) 7.28 (185) 0.39 (10) 5.7%
Circum. inches (mm) 77.22 (1961.3) 76.87 (1952.5) -0.35 (-8.8) -0.4%
Sidewall Height inches (mm) 3.79 (96.25) 4.73 (120.25) 0.94 (24) 24.9%
Revolutions per mile (km) 820.55 (509.87) 824.25 (512.16) 3.7 (2.3) 0.5%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.91 mph (32.04 km/h)
25 mph (40.23 km/h)24.89 mph (40.05 km/h)
30 mph (48.28 km/h)29.87 mph (48.06 km/h)
35 mph (56.33 km/h)34.84 mph (56.07 km/h)
40 mph (64.37 km/h)39.82 mph (64.09 km/h)
45 mph (72.42 km/h)44.8 mph (72.1 km/h)
50 mph (80.47 km/h)49.78 mph (80.11 km/h)
55 mph (88.51 km/h)54.75 mph (88.12 km/h)
60 mph (96.56 km/h)59.73 mph (96.13 km/h)
65 mph (104.61 km/h)64.71 mph (104.14 km/h)
70 mph (112.65 km/h)69.69 mph (112.15 km/h)
75 mph (120.7 km/h)74.66 mph (120.16 km/h)
80 mph (128.75 km/h)79.64 mph (128.17 km/h)
85 mph (136.79 km/h)84.62 mph (136.18 km/h)
90 mph (144.84 km/h)89.6 mph (144.19 km/h)
95 mph (152.89 km/h)94.57 mph (152.2 km/h)
100 mph (160.93 km/h)99.55 mph (160.21 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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