Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
305/50r20 vs 275/50r20 Tire Comparison Side By Side
  305/50-20 275/50-20 Difference
Diameter inches (mm) 32.01 (813) 30.83 (783) -1.18 (-30) -3.7%
Width inches (mm) 12.01 (305) 10.83 (275) -1.18 (-30) -9.8%
Circum. inches (mm) 100.56 (2554.11) 96.85 (2459.87) -3.71 (-94.25) -3.7%
Sidewall Height inches (mm) 6 (152.5) 5.41 (137.5) -0.59 (-15) -9.8%
Revolutions per mile (km) 630.1 (391.52) 654.24 (406.53) 24.14 (15) 3.8%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.26 mph (31 km/h)
25 mph (40.23 km/h)24.08 mph (38.75 km/h)
30 mph (48.28 km/h)28.89 mph (46.5 km/h)
35 mph (56.33 km/h)33.71 mph (54.25 km/h)
40 mph (64.37 km/h)38.52 mph (62 km/h)
45 mph (72.42 km/h)43.34 mph (69.75 km/h)
50 mph (80.47 km/h)48.15 mph (77.5 km/h)
55 mph (88.51 km/h)52.97 mph (85.25 km/h)
60 mph (96.56 km/h)57.79 mph (93 km/h)
65 mph (104.61 km/h)62.6 mph (100.75 km/h)
70 mph (112.65 km/h)67.42 mph (108.5 km/h)
75 mph (120.7 km/h)72.23 mph (116.25 km/h)
80 mph (128.75 km/h)77.05 mph (124 km/h)
85 mph (136.79 km/h)81.86 mph (131.75 km/h)
90 mph (144.84 km/h)86.68 mph (139.5 km/h)
95 mph (152.89 km/h)91.49 mph (147.25 km/h)
100 mph (160.93 km/h)96.31 mph (155 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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