Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
305/70r18 vs 275/70r18 Tire Comparison Side By Side
  305/70-18 275/70-18 Difference
Diameter inches (mm) 34.81 (884.2) 33.16 (842.2) -1.65 (-42) -4.8%
Width inches (mm) 12.01 (305) 10.83 (275) -1.18 (-30) -9.8%
Circum. inches (mm) 109.36 (2777.8) 104.17 (2645.85) -5.19 (-131.95) -4.8%
Sidewall Height inches (mm) 8.41 (213.5) 7.58 (192.5) -0.83 (-21) -9.8%
Revolutions per mile (km) 579.36 (360) 608.25 (377.95) 28.89 (17.95) 5%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.05 mph (30.66 km/h)
25 mph (40.23 km/h)23.81 mph (38.32 km/h)
30 mph (48.28 km/h)28.57 mph (45.99 km/h)
35 mph (56.33 km/h)33.34 mph (53.65 km/h)
40 mph (64.37 km/h)38.1 mph (61.32 km/h)
45 mph (72.42 km/h)42.86 mph (68.98 km/h)
50 mph (80.47 km/h)47.62 mph (76.65 km/h)
55 mph (88.51 km/h)52.39 mph (84.31 km/h)
60 mph (96.56 km/h)57.15 mph (91.97 km/h)
65 mph (104.61 km/h)61.91 mph (99.64 km/h)
70 mph (112.65 km/h)66.67 mph (107.3 km/h)
75 mph (120.7 km/h)71.44 mph (114.97 km/h)
80 mph (128.75 km/h)76.2 mph (122.63 km/h)
85 mph (136.79 km/h)80.96 mph (130.3 km/h)
90 mph (144.84 km/h)85.72 mph (137.96 km/h)
95 mph (152.89 km/h)90.49 mph (145.63 km/h)
100 mph (160.93 km/h)95.25 mph (153.29 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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