Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
315/35r17 vs 390/40r17 Tire Comparison Side By Side
  315/35-17 390/40-17 Difference
Diameter inches (mm) 25.68 (652.3) 29.28 (743.8) 3.6 (91.5) 14%
Width inches (mm) 12.4 (315) 15.35 (390) 2.95 (75) 23.8%
Circum. inches (mm) 80.68 (2049.26) 92 (2336.72) 11.32 (287.46) 14%
Sidewall Height inches (mm) 4.34 (110.25) 6.14 (156) 1.8 (45.75) 41.5%
Revolutions per mile (km) 785.33 (487.98) 688.72 (427.95) -96.61 (-60.03) -12.3%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)22.81 mph (36.7 km/h)
25 mph (40.23 km/h)28.51 mph (45.88 km/h)
30 mph (48.28 km/h)34.21 mph (55.05 km/h)
35 mph (56.33 km/h)39.91 mph (64.23 km/h)
40 mph (64.37 km/h)45.61 mph (73.4 km/h)
45 mph (72.42 km/h)51.31 mph (82.58 km/h)
50 mph (80.47 km/h)57.01 mph (91.75 km/h)
55 mph (88.51 km/h)62.72 mph (100.93 km/h)
60 mph (96.56 km/h)68.42 mph (110.11 km/h)
65 mph (104.61 km/h)74.12 mph (119.28 km/h)
70 mph (112.65 km/h)79.82 mph (128.46 km/h)
75 mph (120.7 km/h)85.52 mph (137.63 km/h)
80 mph (128.75 km/h)91.22 mph (146.81 km/h)
85 mph (136.79 km/h)96.92 mph (155.98 km/h)
90 mph (144.84 km/h)102.62 mph (165.16 km/h)
95 mph (152.89 km/h)108.33 mph (174.33 km/h)
100 mph (160.93 km/h)114.03 mph (183.51 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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