Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
305/45r20 vs 265/70r17 Tire Comparison Side By Side
  305/45-20 265/70-17 Difference
Diameter inches (mm) 30.81 (782.5) 31.61 (802.8) 0.8 (20.3) 2.6%
Width inches (mm) 12.01 (305) 10.43 (265) -1.57 (-40) -13.1%
Circum. inches (mm) 96.78 (2458.3) 99.29 (2522.07) 2.51 (63.77) 2.6%
Sidewall Height inches (mm) 5.4 (137.25) 7.3 (185.5) 1.9 (48.25) 35.2%
Revolutions per mile (km) 654.66 (406.79) 638.1 (396.5) -16.55 (-10.29) -2.5%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.52 mph (33.02 km/h)
25 mph (40.23 km/h)25.65 mph (41.28 km/h)
30 mph (48.28 km/h)30.78 mph (49.53 km/h)
35 mph (56.33 km/h)35.91 mph (57.79 km/h)
40 mph (64.37 km/h)41.04 mph (66.04 km/h)
45 mph (72.42 km/h)46.17 mph (74.3 km/h)
50 mph (80.47 km/h)51.3 mph (82.55 km/h)
55 mph (88.51 km/h)56.43 mph (90.81 km/h)
60 mph (96.56 km/h)61.56 mph (99.07 km/h)
65 mph (104.61 km/h)66.69 mph (107.32 km/h)
70 mph (112.65 km/h)71.82 mph (115.58 km/h)
75 mph (120.7 km/h)76.95 mph (123.83 km/h)
80 mph (128.75 km/h)82.08 mph (132.09 km/h)
85 mph (136.79 km/h)87.21 mph (140.34 km/h)
90 mph (144.84 km/h)92.33 mph (148.6 km/h)
95 mph (152.89 km/h)97.46 mph (156.85 km/h)
100 mph (160.93 km/h)102.59 mph (165.11 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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