Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
125/65r12 vs 235/30r12 Tire Comparison Side By Side
  125/65-12 235/30-12 Difference
Diameter inches (mm) 18.4 (467.3) 17.55 (445.8) -0.85 (-21.5) -4.6%
Width inches (mm) 4.92 (125) 9.25 (235) 4.33 (110) 88%
Circum. inches (mm) 57.8 (1468.07) 55.14 (1400.52) -2.66 (-67.54) -4.6%
Sidewall Height inches (mm) 3.2 (81.25) 2.78 (70.5) -0.42 (-10.75) -13.2%
Revolutions per mile (km) 1096.23 (681.17) 1149.1 (714.02) 52.87 (32.85) 4.8%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.08 mph (30.71 km/h)
25 mph (40.23 km/h)23.85 mph (38.38 km/h)
30 mph (48.28 km/h)28.62 mph (46.06 km/h)
35 mph (56.33 km/h)33.39 mph (53.74 km/h)
40 mph (64.37 km/h)38.16 mph (61.41 km/h)
45 mph (72.42 km/h)42.93 mph (69.09 km/h)
50 mph (80.47 km/h)47.7 mph (76.77 km/h)
55 mph (88.51 km/h)52.47 mph (84.44 km/h)
60 mph (96.56 km/h)57.24 mph (92.12 km/h)
65 mph (104.61 km/h)62.01 mph (99.79 km/h)
70 mph (112.65 km/h)66.78 mph (107.47 km/h)
75 mph (120.7 km/h)71.55 mph (115.15 km/h)
80 mph (128.75 km/h)76.32 mph (122.82 km/h)
85 mph (136.79 km/h)81.09 mph (130.5 km/h)
90 mph (144.84 km/h)85.86 mph (138.18 km/h)
95 mph (152.89 km/h)90.63 mph (145.85 km/h)
100 mph (160.93 km/h)95.4 mph (153.53 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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