Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
215/50r12 vs 205/30r14 Tire Comparison Side By Side
  215/50-12 205/30-14 Difference
Diameter inches (mm) 20.46 (519.8) 18.84 (478.6) -1.62 (-41.2) -7.9%
Width inches (mm) 8.46 (215) 8.07 (205) -0.39 (-10) -4.7%
Circum. inches (mm) 64.29 (1633) 59.2 (1503.57) -5.1 (-129.43) -7.9%
Sidewall Height inches (mm) 4.23 (107.5) 2.42 (61.5) -1.81 (-46) -42.8%
Revolutions per mile (km) 985.51 (612.37) 1070.35 (665.08) 84.84 (52.72) 8.6%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)18.41 mph (29.64 km/h)
25 mph (40.23 km/h)23.02 mph (37.04 km/h)
30 mph (48.28 km/h)27.62 mph (44.45 km/h)
35 mph (56.33 km/h)32.23 mph (51.86 km/h)
40 mph (64.37 km/h)36.83 mph (59.27 km/h)
45 mph (72.42 km/h)41.43 mph (66.68 km/h)
50 mph (80.47 km/h)46.04 mph (74.09 km/h)
55 mph (88.51 km/h)50.64 mph (81.5 km/h)
60 mph (96.56 km/h)55.24 mph (88.91 km/h)
65 mph (104.61 km/h)59.85 mph (96.32 km/h)
70 mph (112.65 km/h)64.45 mph (103.73 km/h)
75 mph (120.7 km/h)69.06 mph (111.13 km/h)
80 mph (128.75 km/h)73.66 mph (118.54 km/h)
85 mph (136.79 km/h)78.26 mph (125.95 km/h)
90 mph (144.84 km/h)82.87 mph (133.36 km/h)
95 mph (152.89 km/h)87.47 mph (140.77 km/h)
100 mph (160.93 km/h)92.07 mph (148.18 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
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
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