Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
305/25r20 vs 325/25r20 Tire Comparison Side By Side
  305/25-20 325/25-20 Difference
Diameter inches (mm) 26 (660.5) 26.4 (670.5) 0.39 (10) 1.5%
Width inches (mm) 12.01 (305) 12.8 (325) 0.79 (20) 6.6%
Circum. inches (mm) 81.69 (2075.02) 82.93 (2106.44) 1.24 (31.42) 1.5%
Sidewall Height inches (mm) 3 (76.25) 3.2 (81.25) 0.2 (5) 6.6%
Revolutions per mile (km) 775.58 (481.92) 764.01 (474.73) -11.57 (-7.19) -1.5%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.3 mph (32.67 km/h)
25 mph (40.23 km/h)25.38 mph (40.84 km/h)
30 mph (48.28 km/h)30.45 mph (49.01 km/h)
35 mph (56.33 km/h)35.53 mph (57.18 km/h)
40 mph (64.37 km/h)40.61 mph (65.35 km/h)
45 mph (72.42 km/h)45.68 mph (73.52 km/h)
50 mph (80.47 km/h)50.76 mph (81.69 km/h)
55 mph (88.51 km/h)55.83 mph (89.85 km/h)
60 mph (96.56 km/h)60.91 mph (98.02 km/h)
65 mph (104.61 km/h)65.98 mph (106.19 km/h)
70 mph (112.65 km/h)71.06 mph (114.36 km/h)
75 mph (120.7 km/h)76.14 mph (122.53 km/h)
80 mph (128.75 km/h)81.21 mph (130.7 km/h)
85 mph (136.79 km/h)86.29 mph (138.87 km/h)
90 mph (144.84 km/h)91.36 mph (147.03 km/h)
95 mph (152.89 km/h)96.44 mph (155.2 km/h)
100 mph (160.93 km/h)101.51 mph (163.37 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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