Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
31/12.5r17 vs 285/70r17 Tire Comparison Side By Side
  31/12.5-17 285/70-17 Difference
Diameter inches (mm) 31.02 (787.96) 32.71 (830.8) 1.69 (42.84) 5.4%
Width inches (mm) 12.52 (318) 11.22 (285) -1.3 (-33) -10.4%
Circum. inches (mm) 97.46 (2475.45) 102.76 (2610.04) 5.3 (134.59) 5.4%
Sidewall Height inches (mm) 7.01 (178.08) 7.85 (199.5) 0.84 (21.42) 12%
Revolutions per mile (km) 650.12 (403.97) 616.6 (383.14) -33.52 (-20.83) -5.2%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)21.09 mph (33.94 km/h)
25 mph (40.23 km/h)26.36 mph (42.42 km/h)
30 mph (48.28 km/h)31.63 mph (50.91 km/h)
35 mph (56.33 km/h)36.9 mph (59.39 km/h)
40 mph (64.37 km/h)42.17 mph (67.87 km/h)
45 mph (72.42 km/h)47.45 mph (76.36 km/h)
50 mph (80.47 km/h)52.72 mph (84.84 km/h)
55 mph (88.51 km/h)57.99 mph (93.33 km/h)
60 mph (96.56 km/h)63.26 mph (101.81 km/h)
65 mph (104.61 km/h)68.53 mph (110.29 km/h)
70 mph (112.65 km/h)73.81 mph (118.78 km/h)
75 mph (120.7 km/h)79.08 mph (127.26 km/h)
80 mph (128.75 km/h)84.35 mph (135.75 km/h)
85 mph (136.79 km/h)89.62 mph (144.23 km/h)
90 mph (144.84 km/h)94.89 mph (152.72 km/h)
95 mph (152.89 km/h)100.16 mph (161.2 km/h)
100 mph (160.93 km/h)105.44 mph (169.68 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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