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 305/25r22 Tire Comparison Side By Side
  245/30-21 305/25-22 Difference
Diameter inches (mm) 26.79 (680.4) 28 (711.3) 1.22 (30.9) 4.5%
Width inches (mm) 9.65 (245) 12.01 (305) 2.36 (60) 24.5%
Circum. inches (mm) 84.16 (2137.54) 87.98 (2234.61) 3.82 (97.08) 4.5%
Sidewall Height inches (mm) 2.89 (73.5) 3 (76.25) 0.11 (2.75) 3.7%
Revolutions per mile (km) 752.9 (467.83) 720.19 (447.5) -32.71 (-20.32) -4.3%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.91 mph (33.65 km/h)
25 mph (40.23 km/h)26.14 mph (42.06 km/h)
30 mph (48.28 km/h)31.36 mph (50.47 km/h)
35 mph (56.33 km/h)36.59 mph (58.89 km/h)
40 mph (64.37 km/h)41.82 mph (67.3 km/h)
45 mph (72.42 km/h)47.04 mph (75.71 km/h)
50 mph (80.47 km/h)52.27 mph (84.12 km/h)
55 mph (88.51 km/h)57.5 mph (92.53 km/h)
60 mph (96.56 km/h)62.72 mph (100.95 km/h)
65 mph (104.61 km/h)67.95 mph (109.36 km/h)
70 mph (112.65 km/h)73.18 mph (117.77 km/h)
75 mph (120.7 km/h)78.41 mph (126.18 km/h)
80 mph (128.75 km/h)83.63 mph (134.59 km/h)
85 mph (136.79 km/h)88.86 mph (143.01 km/h)
90 mph (144.84 km/h)94.09 mph (151.42 km/h)
95 mph (152.89 km/h)99.31 mph (159.83 km/h)
100 mph (160.93 km/h)104.54 mph (168.24 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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