Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
325/25r21 vs 225/60r16 Tire Comparison Side By Side
  325/25-21 225/60-16 Difference
Diameter inches (mm) 27.4 (695.9) 26.63 (676.4) -0.77 (-19.5) -2.8%
Width inches (mm) 12.8 (325) 8.86 (225) -3.94 (-100) -30.8%
Circum. inches (mm) 86.07 (2186.23) 83.66 (2124.97) -2.41 (-61.26) -2.8%
Sidewall Height inches (mm) 3.2 (81.25) 5.31 (135) 2.12 (53.75) 66.2%
Revolutions per mile (km) 736.13 (457.41) 757.35 (470.59) 21.22 (13.19) 2.9%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.44 mph (31.29 km/h)
25 mph (40.23 km/h)24.3 mph (39.11 km/h)
30 mph (48.28 km/h)29.16 mph (46.93 km/h)
35 mph (56.33 km/h)34.02 mph (54.75 km/h)
40 mph (64.37 km/h)38.88 mph (62.57 km/h)
45 mph (72.42 km/h)43.74 mph (70.39 km/h)
50 mph (80.47 km/h)48.6 mph (78.21 km/h)
55 mph (88.51 km/h)53.46 mph (86.03 km/h)
60 mph (96.56 km/h)58.32 mph (93.86 km/h)
65 mph (104.61 km/h)63.18 mph (101.68 km/h)
70 mph (112.65 km/h)68.04 mph (109.5 km/h)
75 mph (120.7 km/h)72.9 mph (117.32 km/h)
80 mph (128.75 km/h)77.76 mph (125.14 km/h)
85 mph (136.79 km/h)82.62 mph (132.96 km/h)
90 mph (144.84 km/h)87.48 mph (140.78 km/h)
95 mph (152.89 km/h)92.34 mph (148.6 km/h)
100 mph (160.93 km/h)97.2 mph (156.43 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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