Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
125/90r15 vs 215/50r17 Tire Comparison Side By Side
  125/90-15 215/50-17 Difference
Diameter inches (mm) 23.86 (606) 25.46 (646.8) 1.61 (40.8) 6.7%
Width inches (mm) 4.92 (125) 8.46 (215) 3.54 (90) 72%
Circum. inches (mm) 74.95 (1903.81) 80 (2031.98) 5.05 (128.18) 6.7%
Sidewall Height inches (mm) 4.43 (112.5) 4.23 (107.5) -0.2 (-5) -4.4%
Revolutions per mile (km) 845.33 (525.26) 792.01 (492.13) -53.32 (-33.13) -6.3%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)21.35 mph (34.35 km/h)
25 mph (40.23 km/h)26.68 mph (42.94 km/h)
30 mph (48.28 km/h)32.02 mph (51.53 km/h)
35 mph (56.33 km/h)37.36 mph (60.12 km/h)
40 mph (64.37 km/h)42.69 mph (68.71 km/h)
45 mph (72.42 km/h)48.03 mph (77.3 km/h)
50 mph (80.47 km/h)53.37 mph (85.88 km/h)
55 mph (88.51 km/h)58.7 mph (94.47 km/h)
60 mph (96.56 km/h)64.04 mph (103.06 km/h)
65 mph (104.61 km/h)69.38 mph (111.65 km/h)
70 mph (112.65 km/h)74.71 mph (120.24 km/h)
75 mph (120.7 km/h)80.05 mph (128.83 km/h)
80 mph (128.75 km/h)85.39 mph (137.42 km/h)
85 mph (136.79 km/h)90.72 mph (146 km/h)
90 mph (144.84 km/h)96.06 mph (154.59 km/h)
95 mph (152.89 km/h)101.4 mph (163.18 km/h)
100 mph (160.93 km/h)106.73 mph (171.77 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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