Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
265/45r21 vs 315/40r21 Tire Comparison Side By Side
  265/45-21 315/40-21 Difference
Diameter inches (mm) 30.39 (771.9) 30.92 (785.4) 0.53 (13.5) 1.7%
Width inches (mm) 10.43 (265) 12.4 (315) 1.97 (50) 18.9%
Circum. inches (mm) 95.47 (2425) 97.14 (2467.41) 1.67 (42.41) 1.7%
Sidewall Height inches (mm) 4.69 (119.25) 4.96 (126) 0.27 (6.75) 5.7%
Revolutions per mile (km) 663.65 (412.37) 652.24 (405.28) -11.41 (-7.09) -1.7%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.35 mph (32.75 km/h)
25 mph (40.23 km/h)25.44 mph (40.94 km/h)
30 mph (48.28 km/h)30.52 mph (49.12 km/h)
35 mph (56.33 km/h)35.61 mph (57.31 km/h)
40 mph (64.37 km/h)40.7 mph (65.5 km/h)
45 mph (72.42 km/h)45.79 mph (73.69 km/h)
50 mph (80.47 km/h)50.87 mph (81.87 km/h)
55 mph (88.51 km/h)55.96 mph (90.06 km/h)
60 mph (96.56 km/h)61.05 mph (98.25 km/h)
65 mph (104.61 km/h)66.14 mph (106.44 km/h)
70 mph (112.65 km/h)71.22 mph (114.62 km/h)
75 mph (120.7 km/h)76.31 mph (122.81 km/h)
80 mph (128.75 km/h)81.4 mph (131 km/h)
85 mph (136.79 km/h)86.49 mph (139.19 km/h)
90 mph (144.84 km/h)91.57 mph (147.37 km/h)
95 mph (152.89 km/h)96.66 mph (155.56 km/h)
100 mph (160.93 km/h)101.75 mph (163.75 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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