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 125/70r15 Tire Comparison Side By Side
  125/90-15 125/70-15 Difference
Diameter inches (mm) 23.86 (606) 21.89 (556) -1.97 (-50) -8.3%
Width inches (mm) 4.92 (125) 4.92 (125) 0 (0) 0%
Circum. inches (mm) 74.95 (1903.81) 68.77 (1746.73) -6.18 (-157.08) -8.3%
Sidewall Height inches (mm) 4.43 (112.5) 3.44 (87.5) -0.98 (-25) -22.2%
Revolutions per mile (km) 845.33 (525.26) 921.35 (572.5) 76.02 (47.24) 9%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)18.35 mph (29.53 km/h)
25 mph (40.23 km/h)22.94 mph (36.91 km/h)
30 mph (48.28 km/h)27.52 mph (44.3 km/h)
35 mph (56.33 km/h)32.11 mph (51.68 km/h)
40 mph (64.37 km/h)36.7 mph (59.06 km/h)
45 mph (72.42 km/h)41.29 mph (66.45 km/h)
50 mph (80.47 km/h)45.87 mph (73.83 km/h)
55 mph (88.51 km/h)50.46 mph (81.21 km/h)
60 mph (96.56 km/h)55.05 mph (88.59 km/h)
65 mph (104.61 km/h)59.64 mph (95.98 km/h)
70 mph (112.65 km/h)64.22 mph (103.36 km/h)
75 mph (120.7 km/h)68.81 mph (110.74 km/h)
80 mph (128.75 km/h)73.4 mph (118.13 km/h)
85 mph (136.79 km/h)77.99 mph (125.51 km/h)
90 mph (144.84 km/h)82.57 mph (132.89 km/h)
95 mph (152.89 km/h)87.16 mph (140.27 km/h)
100 mph (160.93 km/h)91.75 mph (147.66 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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