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 235/45r18 Tire Comparison Side By Side
  255/45-18 235/45-18 Difference
Diameter inches (mm) 27.04 (686.7) 26.33 (668.7) -0.71 (-18) -2.6%
Width inches (mm) 10.04 (255) 9.25 (235) -0.79 (-20) -7.8%
Circum. inches (mm) 84.93 (2157.33) 82.71 (2100.78) -2.23 (-56.55) -2.6%
Sidewall Height inches (mm) 4.52 (114.75) 4.16 (105.75) -0.35 (-9) -7.8%
Revolutions per mile (km) 745.99 (463.53) 766.07 (476.01) 20.08 (12.48) 2.7%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.48 mph (31.34 km/h)
25 mph (40.23 km/h)24.34 mph (39.18 km/h)
30 mph (48.28 km/h)29.21 mph (47.01 km/h)
35 mph (56.33 km/h)34.08 mph (54.85 km/h)
40 mph (64.37 km/h)38.95 mph (62.69 km/h)
45 mph (72.42 km/h)43.82 mph (70.52 km/h)
50 mph (80.47 km/h)48.69 mph (78.36 km/h)
55 mph (88.51 km/h)53.56 mph (86.19 km/h)
60 mph (96.56 km/h)58.43 mph (94.03 km/h)
65 mph (104.61 km/h)63.3 mph (101.87 km/h)
70 mph (112.65 km/h)68.17 mph (109.7 km/h)
75 mph (120.7 km/h)73.03 mph (117.54 km/h)
80 mph (128.75 km/h)77.9 mph (125.37 km/h)
85 mph (136.79 km/h)82.77 mph (133.21 km/h)
90 mph (144.84 km/h)87.64 mph (141.04 km/h)
95 mph (152.89 km/h)92.51 mph (148.88 km/h)
100 mph (160.93 km/h)97.38 mph (156.72 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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