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 31/10.5r15 Tire Comparison Side By Side
  325/60-15 31/10.5-15 Difference
Diameter inches (mm) 30.35 (771) 30.98 (786.84) 0.62 (15.84) 2.1%
Width inches (mm) 12.8 (325) 10.51 (267) -2.28 (-58) -17.8%
Circum. inches (mm) 95.36 (2422.17) 97.32 (2471.93) 1.96 (49.76) 2.1%
Sidewall Height inches (mm) 7.68 (195) 7.99 (202.92) 0.31 (7.92) 4.1%
Revolutions per mile (km) 664.42 (412.85) 651.05 (404.54) -13.38 (-8.31) -2%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.41 mph (32.85 km/h)
25 mph (40.23 km/h)25.51 mph (41.06 km/h)
30 mph (48.28 km/h)30.62 mph (49.27 km/h)
35 mph (56.33 km/h)35.72 mph (57.48 km/h)
40 mph (64.37 km/h)40.82 mph (65.7 km/h)
45 mph (72.42 km/h)45.92 mph (73.91 km/h)
50 mph (80.47 km/h)51.03 mph (82.12 km/h)
55 mph (88.51 km/h)56.13 mph (90.33 km/h)
60 mph (96.56 km/h)61.23 mph (98.54 km/h)
65 mph (104.61 km/h)66.34 mph (106.76 km/h)
70 mph (112.65 km/h)71.44 mph (114.97 km/h)
75 mph (120.7 km/h)76.54 mph (123.18 km/h)
80 mph (128.75 km/h)81.64 mph (131.39 km/h)
85 mph (136.79 km/h)86.75 mph (139.6 km/h)
90 mph (144.84 km/h)91.85 mph (147.82 km/h)
95 mph (152.89 km/h)96.95 mph (156.03 km/h)
100 mph (160.93 km/h)102.05 mph (164.24 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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