Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
225/40r14 vs 235/30r14 Tire Comparison Side By Side
  225/40-14 235/30-14 Difference
Diameter inches (mm) 21.09 (535.6) 19.55 (496.6) -1.54 (-39) -7.3%
Width inches (mm) 8.86 (225) 9.25 (235) 0.39 (10) 4.4%
Circum. inches (mm) 66.25 (1682.64) 61.42 (1560.11) -4.82 (-122.52) -7.3%
Sidewall Height inches (mm) 3.54 (90) 2.78 (70.5) -0.77 (-19.5) -21.7%
Revolutions per mile (km) 956.44 (594.3) 1031.55 (640.98) 75.11 (46.67) 7.9%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)18.54 mph (29.84 km/h)
25 mph (40.23 km/h)23.18 mph (37.3 km/h)
30 mph (48.28 km/h)27.82 mph (44.76 km/h)
35 mph (56.33 km/h)32.45 mph (52.23 km/h)
40 mph (64.37 km/h)37.09 mph (59.69 km/h)
45 mph (72.42 km/h)41.72 mph (67.15 km/h)
50 mph (80.47 km/h)46.36 mph (74.61 km/h)
55 mph (88.51 km/h)51 mph (82.07 km/h)
60 mph (96.56 km/h)55.63 mph (89.53 km/h)
65 mph (104.61 km/h)60.27 mph (96.99 km/h)
70 mph (112.65 km/h)64.9 mph (104.45 km/h)
75 mph (120.7 km/h)69.54 mph (111.91 km/h)
80 mph (128.75 km/h)74.17 mph (119.37 km/h)
85 mph (136.79 km/h)78.81 mph (126.83 km/h)
90 mph (144.84 km/h)83.45 mph (134.29 km/h)
95 mph (152.89 km/h)88.08 mph (141.76 km/h)
100 mph (160.93 km/h)92.72 mph (149.22 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
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
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