Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
325/80r16 vs 37/12.5r16 Tire Comparison Side By Side
  325/80-16 37/12.5-16 Difference
Diameter inches (mm) 36.47 (926.4) 37.03 (940.64) 0.56 (14.24) 1.5%
Width inches (mm) 12.8 (325) 12.52 (318) -0.28 (-7) -2.2%
Circum. inches (mm) 114.58 (2910.37) 116.34 (2955.11) 1.76 (44.74) 1.5%
Sidewall Height inches (mm) 10.24 (260) 10.52 (267.12) 0.28 (7.12) 2.7%
Revolutions per mile (km) 552.97 (343.6) 544.6 (338.4) -8.37 (-5.2) -1.5%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.31 mph (32.68 km/h)
25 mph (40.23 km/h)25.38 mph (40.85 km/h)
30 mph (48.28 km/h)30.46 mph (49.02 km/h)
35 mph (56.33 km/h)35.54 mph (57.19 km/h)
40 mph (64.37 km/h)40.61 mph (65.36 km/h)
45 mph (72.42 km/h)45.69 mph (73.53 km/h)
50 mph (80.47 km/h)50.77 mph (81.7 km/h)
55 mph (88.51 km/h)55.85 mph (89.87 km/h)
60 mph (96.56 km/h)60.92 mph (98.05 km/h)
65 mph (104.61 km/h)66 mph (106.22 km/h)
70 mph (112.65 km/h)71.08 mph (114.39 km/h)
75 mph (120.7 km/h)76.15 mph (122.56 km/h)
80 mph (128.75 km/h)81.23 mph (130.73 km/h)
85 mph (136.79 km/h)86.31 mph (138.9 km/h)
90 mph (144.84 km/h)91.38 mph (147.07 km/h)
95 mph (152.89 km/h)96.46 mph (155.24 km/h)
100 mph (160.93 km/h)101.54 mph (163.41 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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