Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
275/45r18 vs 275/40r20 Tire Comparison Side By Side
  275/45-18 275/40-20 Difference
Diameter inches (mm) 27.74 (704.7) 28.66 (728) 0.92 (23.3) 3.3%
Width inches (mm) 10.83 (275) 10.83 (275) 0 (0) 0%
Circum. inches (mm) 87.16 (2213.88) 90.04 (2287.08) 2.88 (73.2) 3.3%
Sidewall Height inches (mm) 4.87 (123.75) 4.33 (110) -0.54 (-13.75) -11.1%
Revolutions per mile (km) 726.93 (451.69) 703.67 (437.24) -23.27 (-14.46) -3.2%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.66 mph (33.25 km/h)
25 mph (40.23 km/h)25.83 mph (41.56 km/h)
30 mph (48.28 km/h)30.99 mph (49.88 km/h)
35 mph (56.33 km/h)36.16 mph (58.19 km/h)
40 mph (64.37 km/h)41.32 mph (66.5 km/h)
45 mph (72.42 km/h)46.49 mph (74.82 km/h)
50 mph (80.47 km/h)51.65 mph (83.13 km/h)
55 mph (88.51 km/h)56.82 mph (91.44 km/h)
60 mph (96.56 km/h)61.98 mph (99.75 km/h)
65 mph (104.61 km/h)67.15 mph (108.07 km/h)
70 mph (112.65 km/h)72.31 mph (116.38 km/h)
75 mph (120.7 km/h)77.48 mph (124.69 km/h)
80 mph (128.75 km/h)82.65 mph (133 km/h)
85 mph (136.79 km/h)87.81 mph (141.32 km/h)
90 mph (144.84 km/h)92.98 mph (149.63 km/h)
95 mph (152.89 km/h)98.14 mph (157.94 km/h)
100 mph (160.93 km/h)103.31 mph (166.26 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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