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 175/65r15 Tire Comparison Side By Side
  125/90-15 175/65-15 Difference
Diameter inches (mm) 23.86 (606) 23.96 (608.5) 0.1 (2.5) 0.4%
Width inches (mm) 4.92 (125) 6.89 (175) 1.97 (50) 40%
Circum. inches (mm) 74.95 (1903.81) 75.26 (1911.66) 0.31 (7.85) 0.4%
Sidewall Height inches (mm) 4.43 (112.5) 4.48 (113.75) 0.05 (1.25) 1.1%
Revolutions per mile (km) 845.33 (525.26) 841.86 (523.1) -3.47 (-2.16) -0.4%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.08 mph (32.32 km/h)
25 mph (40.23 km/h)25.1 mph (40.4 km/h)
30 mph (48.28 km/h)30.12 mph (48.48 km/h)
35 mph (56.33 km/h)35.14 mph (56.56 km/h)
40 mph (64.37 km/h)40.17 mph (64.64 km/h)
45 mph (72.42 km/h)45.19 mph (72.72 km/h)
50 mph (80.47 km/h)50.21 mph (80.8 km/h)
55 mph (88.51 km/h)55.23 mph (88.88 km/h)
60 mph (96.56 km/h)60.25 mph (96.96 km/h)
65 mph (104.61 km/h)65.27 mph (105.04 km/h)
70 mph (112.65 km/h)70.29 mph (113.12 km/h)
75 mph (120.7 km/h)75.31 mph (121.2 km/h)
80 mph (128.75 km/h)80.33 mph (129.28 km/h)
85 mph (136.79 km/h)85.35 mph (137.36 km/h)
90 mph (144.84 km/h)90.37 mph (145.44 km/h)
95 mph (152.89 km/h)95.39 mph (153.52 km/h)
100 mph (160.93 km/h)100.41 mph (161.6 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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