Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
235/50r18 vs 235/45r18 Tire Comparison Side By Side
  235/50-18 235/45-18 Difference
Diameter inches (mm) 27.25 (692.2) 26.33 (668.7) -0.93 (-23.5) -3.4%
Width inches (mm) 9.25 (235) 9.25 (235) 0 (0) 0%
Circum. inches (mm) 85.61 (2174.61) 82.71 (2100.78) -2.91 (-73.83) -3.4%
Sidewall Height inches (mm) 4.63 (117.5) 4.16 (105.75) -0.46 (-11.75) -10%
Revolutions per mile (km) 740.06 (459.85) 766.07 (476.01) 26.01 (16.16) 3.5%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.32 mph (31.09 km/h)
25 mph (40.23 km/h)24.15 mph (38.87 km/h)
30 mph (48.28 km/h)28.98 mph (46.64 km/h)
35 mph (56.33 km/h)33.81 mph (54.41 km/h)
40 mph (64.37 km/h)38.64 mph (62.19 km/h)
45 mph (72.42 km/h)43.47 mph (69.96 km/h)
50 mph (80.47 km/h)48.3 mph (77.74 km/h)
55 mph (88.51 km/h)53.13 mph (85.51 km/h)
60 mph (96.56 km/h)57.96 mph (93.28 km/h)
65 mph (104.61 km/h)62.79 mph (101.06 km/h)
70 mph (112.65 km/h)67.62 mph (108.83 km/h)
75 mph (120.7 km/h)72.45 mph (116.6 km/h)
80 mph (128.75 km/h)77.28 mph (124.38 km/h)
85 mph (136.79 km/h)82.11 mph (132.15 km/h)
90 mph (144.84 km/h)86.94 mph (139.92 km/h)
95 mph (152.89 km/h)91.77 mph (147.7 km/h)
100 mph (160.93 km/h)96.61 mph (155.47 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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