Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
245/30r21 vs 225/40r19 Tire Comparison Side By Side
  245/30-21 225/40-19 Difference
Diameter inches (mm) 26.79 (680.4) 26.09 (662.6) -0.7 (-17.8) -2.6%
Width inches (mm) 9.65 (245) 8.86 (225) -0.79 (-20) -8.2%
Circum. inches (mm) 84.16 (2137.54) 81.95 (2081.62) -2.2 (-55.92) -2.6%
Sidewall Height inches (mm) 2.89 (73.5) 3.54 (90) 0.65 (16.5) 22.4%
Revolutions per mile (km) 752.9 (467.83) 773.12 (480.39) 20.23 (12.57) 2.7%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.48 mph (31.34 km/h)
25 mph (40.23 km/h)24.35 mph (39.18 km/h)
30 mph (48.28 km/h)29.22 mph (47.02 km/h)
35 mph (56.33 km/h)34.08 mph (54.85 km/h)
40 mph (64.37 km/h)38.95 mph (62.69 km/h)
45 mph (72.42 km/h)43.82 mph (70.53 km/h)
50 mph (80.47 km/h)48.69 mph (78.36 km/h)
55 mph (88.51 km/h)53.56 mph (86.2 km/h)
60 mph (96.56 km/h)58.43 mph (94.03 km/h)
65 mph (104.61 km/h)63.3 mph (101.87 km/h)
70 mph (112.65 km/h)68.17 mph (109.71 km/h)
75 mph (120.7 km/h)73.04 mph (117.54 km/h)
80 mph (128.75 km/h)77.91 mph (125.38 km/h)
85 mph (136.79 km/h)82.78 mph (133.22 km/h)
90 mph (144.84 km/h)87.65 mph (141.05 km/h)
95 mph (152.89 km/h)92.51 mph (148.89 km/h)
100 mph (160.93 km/h)97.38 mph (156.72 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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