Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
285/40r18 vs 245/40r18 Tire Comparison Side By Side
  285/40-18 245/40-18 Difference
Diameter inches (mm) 26.98 (685.2) 25.72 (653.2) -1.26 (-32) -4.7%
Width inches (mm) 11.22 (285) 9.65 (245) -1.57 (-40) -14%
Circum. inches (mm) 84.75 (2152.62) 80.79 (2052.09) -3.96 (-100.53) -4.7%
Sidewall Height inches (mm) 4.49 (114) 3.86 (98) -0.63 (-16) -14%
Revolutions per mile (km) 747.62 (464.55) 784.25 (487.31) 36.63 (22.76) 4.9%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.07 mph (30.68 km/h)
25 mph (40.23 km/h)23.83 mph (38.35 km/h)
30 mph (48.28 km/h)28.6 mph (46.03 km/h)
35 mph (56.33 km/h)33.37 mph (53.7 km/h)
40 mph (64.37 km/h)38.13 mph (61.37 km/h)
45 mph (72.42 km/h)42.9 mph (69.04 km/h)
50 mph (80.47 km/h)47.66 mph (76.71 km/h)
55 mph (88.51 km/h)52.43 mph (84.38 km/h)
60 mph (96.56 km/h)57.2 mph (92.05 km/h)
65 mph (104.61 km/h)61.96 mph (99.72 km/h)
70 mph (112.65 km/h)66.73 mph (107.39 km/h)
75 mph (120.7 km/h)71.5 mph (115.06 km/h)
80 mph (128.75 km/h)76.26 mph (122.74 km/h)
85 mph (136.79 km/h)81.03 mph (130.41 km/h)
90 mph (144.84 km/h)85.8 mph (138.08 km/h)
95 mph (152.89 km/h)90.56 mph (145.75 km/h)
100 mph (160.93 km/h)95.33 mph (153.42 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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