Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
155/85r18 vs 235/60r18 Tire Comparison Side By Side
  155/85-18 235/60-18 Difference
Diameter inches (mm) 28.37 (720.7) 29.1 (739.2) 0.73 (18.5) 2.6%
Width inches (mm) 6.1 (155) 9.25 (235) 3.15 (80) 51.6%
Circum. inches (mm) 89.14 (2264.15) 91.43 (2322.27) 2.29 (58.12) 2.6%
Sidewall Height inches (mm) 5.19 (131.75) 5.55 (141) 0.36 (9.25) 7%
Revolutions per mile (km) 710.8 (441.67) 693.01 (430.61) -17.79 (-11.05) -2.5%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.51 mph (33.01 km/h)
25 mph (40.23 km/h)25.64 mph (41.27 km/h)
30 mph (48.28 km/h)30.77 mph (49.52 km/h)
35 mph (56.33 km/h)35.9 mph (57.77 km/h)
40 mph (64.37 km/h)41.03 mph (66.03 km/h)
45 mph (72.42 km/h)46.16 mph (74.28 km/h)
50 mph (80.47 km/h)51.28 mph (82.53 km/h)
55 mph (88.51 km/h)56.41 mph (90.79 km/h)
60 mph (96.56 km/h)61.54 mph (99.04 km/h)
65 mph (104.61 km/h)66.67 mph (107.29 km/h)
70 mph (112.65 km/h)71.8 mph (115.55 km/h)
75 mph (120.7 km/h)76.93 mph (123.8 km/h)
80 mph (128.75 km/h)82.05 mph (132.05 km/h)
85 mph (136.79 km/h)87.18 mph (140.31 km/h)
90 mph (144.84 km/h)92.31 mph (148.56 km/h)
95 mph (152.89 km/h)97.44 mph (156.81 km/h)
100 mph (160.93 km/h)102.57 mph (165.07 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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