Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
325/60r15 vs 375/60r15 Tire Comparison Side By Side
  325/60-15 375/60-15 Difference
Diameter inches (mm) 30.35 (771) 32.72 (831) 2.36 (60) 7.8%
Width inches (mm) 12.8 (325) 14.76 (375) 1.97 (50) 15.4%
Circum. inches (mm) 95.36 (2422.17) 102.78 (2610.66) 7.42 (188.5) 7.8%
Sidewall Height inches (mm) 7.68 (195) 8.86 (225) 1.18 (30) 15.4%
Revolutions per mile (km) 664.42 (412.85) 616.45 (383.04) -47.97 (-29.81) -7.2%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)21.56 mph (34.69 km/h)
25 mph (40.23 km/h)26.95 mph (43.36 km/h)
30 mph (48.28 km/h)32.33 mph (52.04 km/h)
35 mph (56.33 km/h)37.72 mph (60.71 km/h)
40 mph (64.37 km/h)43.11 mph (69.38 km/h)
45 mph (72.42 km/h)48.5 mph (78.06 km/h)
50 mph (80.47 km/h)53.89 mph (86.73 km/h)
55 mph (88.51 km/h)59.28 mph (95.4 km/h)
60 mph (96.56 km/h)64.67 mph (104.08 km/h)
65 mph (104.61 km/h)70.06 mph (112.75 km/h)
70 mph (112.65 km/h)75.45 mph (121.42 km/h)
75 mph (120.7 km/h)80.84 mph (130.09 km/h)
80 mph (128.75 km/h)86.23 mph (138.77 km/h)
85 mph (136.79 km/h)91.61 mph (147.44 km/h)
90 mph (144.84 km/h)97 mph (156.11 km/h)
95 mph (152.89 km/h)102.39 mph (164.79 km/h)
100 mph (160.93 km/h)107.78 mph (173.46 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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