Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
235/85r15 vs 31/10.5r15 Tire Comparison Side By Side
  235/85-15 31/10.5-15 Difference
Diameter inches (mm) 30.73 (780.5) 30.98 (786.84) 0.25 (6.34) 0.8%
Width inches (mm) 9.25 (235) 10.51 (267) 1.26 (32) 13.6%
Circum. inches (mm) 96.54 (2452.01) 97.32 (2471.93) 0.78 (19.92) 0.8%
Sidewall Height inches (mm) 7.86 (199.75) 7.99 (202.92) 0.12 (3.17) 1.6%
Revolutions per mile (km) 656.34 (407.83) 651.05 (404.54) -5.29 (-3.29) -0.8%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.16 mph (32.45 km/h)
25 mph (40.23 km/h)25.2 mph (40.56 km/h)
30 mph (48.28 km/h)30.24 mph (48.67 km/h)
35 mph (56.33 km/h)35.28 mph (56.78 km/h)
40 mph (64.37 km/h)40.32 mph (64.9 km/h)
45 mph (72.42 km/h)45.37 mph (73.01 km/h)
50 mph (80.47 km/h)50.41 mph (81.12 km/h)
55 mph (88.51 km/h)55.45 mph (89.23 km/h)
60 mph (96.56 km/h)60.49 mph (97.35 km/h)
65 mph (104.61 km/h)65.53 mph (105.46 km/h)
70 mph (112.65 km/h)70.57 mph (113.57 km/h)
75 mph (120.7 km/h)75.61 mph (121.68 km/h)
80 mph (128.75 km/h)80.65 mph (129.79 km/h)
85 mph (136.79 km/h)85.69 mph (137.91 km/h)
90 mph (144.84 km/h)90.73 mph (146.02 km/h)
95 mph (152.89 km/h)95.77 mph (154.13 km/h)
100 mph (160.93 km/h)100.81 mph (162.24 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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