Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
305/55r20 vs 275/65r20 Tire Comparison Side By Side
  305/55-20 275/65-20 Difference
Diameter inches (mm) 33.21 (843.5) 34.07 (865.5) 0.87 (22) 2.6%
Width inches (mm) 12.01 (305) 10.83 (275) -1.18 (-30) -9.8%
Circum. inches (mm) 104.33 (2649.93) 107.05 (2719.05) 2.72 (69.12) 2.6%
Sidewall Height inches (mm) 6.6 (167.75) 7.04 (178.75) 0.43 (11) 6.6%
Revolutions per mile (km) 607.31 (377.37) 591.88 (367.78) -15.44 (-9.59) -2.5%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.52 mph (33.03 km/h)
25 mph (40.23 km/h)25.65 mph (41.28 km/h)
30 mph (48.28 km/h)30.78 mph (49.54 km/h)
35 mph (56.33 km/h)35.91 mph (57.8 km/h)
40 mph (64.37 km/h)41.04 mph (66.05 km/h)
45 mph (72.42 km/h)46.17 mph (74.31 km/h)
50 mph (80.47 km/h)51.3 mph (82.57 km/h)
55 mph (88.51 km/h)56.43 mph (90.82 km/h)
60 mph (96.56 km/h)61.56 mph (99.08 km/h)
65 mph (104.61 km/h)66.7 mph (107.34 km/h)
70 mph (112.65 km/h)71.83 mph (115.59 km/h)
75 mph (120.7 km/h)76.96 mph (123.85 km/h)
80 mph (128.75 km/h)82.09 mph (132.11 km/h)
85 mph (136.79 km/h)87.22 mph (140.36 km/h)
90 mph (144.84 km/h)92.35 mph (148.62 km/h)
95 mph (152.89 km/h)97.48 mph (156.88 km/h)
100 mph (160.93 km/h)102.61 mph (165.13 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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