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 315/50r15 Tire Comparison Side By Side
  325/60-15 315/50-15 Difference
Diameter inches (mm) 30.35 (771) 27.4 (696) -2.95 (-75) -9.7%
Width inches (mm) 12.8 (325) 12.4 (315) -0.39 (-10) -3.1%
Circum. inches (mm) 95.36 (2422.17) 86.08 (2186.55) -9.28 (-235.62) -9.7%
Sidewall Height inches (mm) 7.68 (195) 6.2 (157.5) -1.48 (-37.5) -19.2%
Revolutions per mile (km) 664.42 (412.85) 736.02 (457.34) 71.6 (44.49) 10.8%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)18.05 mph (29.06 km/h)
25 mph (40.23 km/h)22.57 mph (36.32 km/h)
30 mph (48.28 km/h)27.08 mph (43.58 km/h)
35 mph (56.33 km/h)31.6 mph (50.85 km/h)
40 mph (64.37 km/h)36.11 mph (58.11 km/h)
45 mph (72.42 km/h)40.62 mph (65.38 km/h)
50 mph (80.47 km/h)45.14 mph (72.64 km/h)
55 mph (88.51 km/h)49.65 mph (79.9 km/h)
60 mph (96.56 km/h)54.16 mph (87.17 km/h)
65 mph (104.61 km/h)58.68 mph (94.43 km/h)
70 mph (112.65 km/h)63.19 mph (101.7 km/h)
75 mph (120.7 km/h)67.7 mph (108.96 km/h)
80 mph (128.75 km/h)72.22 mph (116.22 km/h)
85 mph (136.79 km/h)76.73 mph (123.49 km/h)
90 mph (144.84 km/h)81.25 mph (130.75 km/h)
95 mph (152.89 km/h)85.76 mph (138.02 km/h)
100 mph (160.93 km/h)90.27 mph (145.28 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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