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 225/30r14 Tire Comparison Side By Side
  225/40-14 225/30-14 Difference
Diameter inches (mm) 21.09 (535.6) 19.31 (490.6) -1.77 (-45) -8.4%
Width inches (mm) 8.86 (225) 8.86 (225) 0 (0) 0%
Circum. inches (mm) 66.25 (1682.64) 60.68 (1541.27) -5.57 (-141.37) -8.4%
Sidewall Height inches (mm) 3.54 (90) 2.66 (67.5) -0.89 (-22.5) -25%
Revolutions per mile (km) 956.44 (594.3) 1044.17 (648.82) 87.73 (54.51) 9.2%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)18.32 mph (29.48 km/h)
25 mph (40.23 km/h)22.9 mph (36.85 km/h)
30 mph (48.28 km/h)27.48 mph (44.22 km/h)
35 mph (56.33 km/h)32.06 mph (51.59 km/h)
40 mph (64.37 km/h)36.64 mph (58.97 km/h)
45 mph (72.42 km/h)41.22 mph (66.34 km/h)
50 mph (80.47 km/h)45.8 mph (73.71 km/h)
55 mph (88.51 km/h)50.38 mph (81.08 km/h)
60 mph (96.56 km/h)54.96 mph (88.45 km/h)
65 mph (104.61 km/h)59.54 mph (95.82 km/h)
70 mph (112.65 km/h)64.12 mph (103.19 km/h)
75 mph (120.7 km/h)68.7 mph (110.56 km/h)
80 mph (128.75 km/h)73.28 mph (117.93 km/h)
85 mph (136.79 km/h)77.86 mph (125.3 km/h)
90 mph (144.84 km/h)82.44 mph (132.67 km/h)
95 mph (152.89 km/h)87.02 mph (140.04 km/h)
100 mph (160.93 km/h)91.6 mph (147.41 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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