Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
255/45r18 vs 275/40r18 Tire Comparison Side By Side
  255/45-18 275/40-18 Difference
Diameter inches (mm) 27.04 (686.7) 26.66 (677.2) -0.37 (-9.5) -1.4%
Width inches (mm) 10.04 (255) 10.83 (275) 0.79 (20) 7.8%
Circum. inches (mm) 84.93 (2157.33) 83.76 (2127.49) -1.18 (-29.85) -1.4%
Sidewall Height inches (mm) 4.52 (114.75) 4.33 (110) -0.19 (-4.75) -4.1%
Revolutions per mile (km) 745.99 (463.53) 756.45 (470.04) 10.46 (6.5) 1.4%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.72 mph (31.74 km/h)
25 mph (40.23 km/h)24.65 mph (39.68 km/h)
30 mph (48.28 km/h)29.58 mph (47.61 km/h)
35 mph (56.33 km/h)34.52 mph (55.55 km/h)
40 mph (64.37 km/h)39.45 mph (63.48 km/h)
45 mph (72.42 km/h)44.38 mph (71.42 km/h)
50 mph (80.47 km/h)49.31 mph (79.35 km/h)
55 mph (88.51 km/h)54.24 mph (87.29 km/h)
60 mph (96.56 km/h)59.17 mph (95.22 km/h)
65 mph (104.61 km/h)64.1 mph (103.16 km/h)
70 mph (112.65 km/h)69.03 mph (111.1 km/h)
75 mph (120.7 km/h)73.96 mph (119.03 km/h)
80 mph (128.75 km/h)78.89 mph (126.97 km/h)
85 mph (136.79 km/h)83.82 mph (134.9 km/h)
90 mph (144.84 km/h)88.75 mph (142.84 km/h)
95 mph (152.89 km/h)93.69 mph (150.77 km/h)
100 mph (160.93 km/h)98.62 mph (158.71 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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