Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
295/30r21 vs 315/30r21 Tire Comparison Side By Side
  295/30-21 315/30-21 Difference
Diameter inches (mm) 27.97 (710.4) 28.44 (722.4) 0.47 (12) 1.7%
Width inches (mm) 11.61 (295) 12.4 (315) 0.79 (20) 6.8%
Circum. inches (mm) 87.87 (2231.79) 89.35 (2269.49) 1.48 (37.7) 1.7%
Sidewall Height inches (mm) 3.48 (88.5) 3.72 (94.5) 0.24 (6) 6.8%
Revolutions per mile (km) 721.1 (448.07) 709.12 (440.63) -11.98 (-7.44) -1.7%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.34 mph (32.73 km/h)
25 mph (40.23 km/h)25.42 mph (40.91 km/h)
30 mph (48.28 km/h)30.51 mph (49.1 km/h)
35 mph (56.33 km/h)35.59 mph (57.28 km/h)
40 mph (64.37 km/h)40.68 mph (65.46 km/h)
45 mph (72.42 km/h)45.76 mph (73.64 km/h)
50 mph (80.47 km/h)50.84 mph (81.83 km/h)
55 mph (88.51 km/h)55.93 mph (90.01 km/h)
60 mph (96.56 km/h)61.01 mph (98.19 km/h)
65 mph (104.61 km/h)66.1 mph (106.37 km/h)
70 mph (112.65 km/h)71.18 mph (114.56 km/h)
75 mph (120.7 km/h)76.27 mph (122.74 km/h)
80 mph (128.75 km/h)81.35 mph (130.92 km/h)
85 mph (136.79 km/h)86.44 mph (139.11 km/h)
90 mph (144.84 km/h)91.52 mph (147.29 km/h)
95 mph (152.89 km/h)96.6 mph (155.47 km/h)
100 mph (160.93 km/h)101.69 mph (163.65 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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