Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
235/30r18 vs 215/25r18 Tire Comparison Side By Side
  235/30-18 215/25-18 Difference
Diameter inches (mm) 23.55 (598.2) 22.23 (564.7) -1.32 (-33.5) -5.6%
Width inches (mm) 9.25 (235) 8.46 (215) -0.79 (-20) -8.5%
Circum. inches (mm) 73.99 (1879.3) 69.84 (1774.06) -4.14 (-105.24) -5.6%
Sidewall Height inches (mm) 2.78 (70.5) 2.12 (53.75) -0.66 (-16.75) -23.8%
Revolutions per mile (km) 856.35 (532.11) 907.15 (563.68) 50.8 (31.57) 5.9%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)18.88 mph (30.38 km/h)
25 mph (40.23 km/h)23.6 mph (37.98 km/h)
30 mph (48.28 km/h)28.32 mph (45.58 km/h)
35 mph (56.33 km/h)33.04 mph (53.17 km/h)
40 mph (64.37 km/h)37.76 mph (60.77 km/h)
45 mph (72.42 km/h)42.48 mph (68.36 km/h)
50 mph (80.47 km/h)47.2 mph (75.96 km/h)
55 mph (88.51 km/h)51.92 mph (83.56 km/h)
60 mph (96.56 km/h)56.64 mph (91.15 km/h)
65 mph (104.61 km/h)61.36 mph (98.75 km/h)
70 mph (112.65 km/h)66.08 mph (106.35 km/h)
75 mph (120.7 km/h)70.8 mph (113.94 km/h)
80 mph (128.75 km/h)75.52 mph (121.54 km/h)
85 mph (136.79 km/h)80.24 mph (129.13 km/h)
90 mph (144.84 km/h)84.96 mph (136.73 km/h)
95 mph (152.89 km/h)89.68 mph (144.33 km/h)
100 mph (160.93 km/h)94.4 mph (151.92 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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