Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
245/40r21 vs 245/50r19 Tire Comparison Side By Side
  245/40-21 245/50-19 Difference
Diameter inches (mm) 28.72 (729.4) 28.65 (727.6) -0.07 (-1.8) -0.2%
Width inches (mm) 9.65 (245) 9.65 (245) 0 (0) 0%
Circum. inches (mm) 90.22 (2291.48) 89.99 (2285.82) -0.22 (-5.65) -0.2%
Sidewall Height inches (mm) 3.86 (98) 4.82 (122.5) 0.96 (24.5) 25%
Revolutions per mile (km) 702.32 (436.4) 704.05 (437.48) 1.74 (1.08) 0.2%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.95 mph (32.11 km/h)
25 mph (40.23 km/h)24.94 mph (40.13 km/h)
30 mph (48.28 km/h)29.93 mph (48.16 km/h)
35 mph (56.33 km/h)34.91 mph (56.19 km/h)
40 mph (64.37 km/h)39.9 mph (64.22 km/h)
45 mph (72.42 km/h)44.89 mph (72.24 km/h)
50 mph (80.47 km/h)49.88 mph (80.27 km/h)
55 mph (88.51 km/h)54.86 mph (88.3 km/h)
60 mph (96.56 km/h)59.85 mph (96.32 km/h)
65 mph (104.61 km/h)64.84 mph (104.35 km/h)
70 mph (112.65 km/h)69.83 mph (112.38 km/h)
75 mph (120.7 km/h)74.81 mph (120.4 km/h)
80 mph (128.75 km/h)79.8 mph (128.43 km/h)
85 mph (136.79 km/h)84.79 mph (136.46 km/h)
90 mph (144.84 km/h)89.78 mph (144.48 km/h)
95 mph (152.89 km/h)94.77 mph (152.51 km/h)
100 mph (160.93 km/h)99.75 mph (160.54 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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