Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
125/80r15 vs 145/90r16 Tire Comparison Side By Side
  125/80-15 145/90-16 Difference
Diameter inches (mm) 22.87 (581) 26.28 (667.4) 3.4 (86.4) 14.9%
Width inches (mm) 4.92 (125) 5.71 (145) 0.79 (20) 16%
Circum. inches (mm) 71.86 (1825.27) 82.55 (2096.7) 10.69 (271.43) 14.9%
Sidewall Height inches (mm) 3.94 (100) 5.14 (130.5) 1.2 (30.5) 30.5%
Revolutions per mile (km) 881.7 (547.86) 767.56 (476.94) -114.14 (-70.93) -12.9%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)22.97 mph (36.97 km/h)
25 mph (40.23 km/h)28.72 mph (46.22 km/h)
30 mph (48.28 km/h)34.46 mph (55.46 km/h)
35 mph (56.33 km/h)40.2 mph (64.7 km/h)
40 mph (64.37 km/h)45.95 mph (73.95 km/h)
45 mph (72.42 km/h)51.69 mph (83.19 km/h)
50 mph (80.47 km/h)57.44 mph (92.43 km/h)
55 mph (88.51 km/h)63.18 mph (101.68 km/h)
60 mph (96.56 km/h)68.92 mph (110.92 km/h)
65 mph (104.61 km/h)74.67 mph (120.16 km/h)
70 mph (112.65 km/h)80.41 mph (129.41 km/h)
75 mph (120.7 km/h)86.15 mph (138.65 km/h)
80 mph (128.75 km/h)91.9 mph (147.89 km/h)
85 mph (136.79 km/h)97.64 mph (157.14 km/h)
90 mph (144.84 km/h)103.38 mph (166.38 km/h)
95 mph (152.89 km/h)109.13 mph (175.62 km/h)
100 mph (160.93 km/h)114.87 mph (184.87 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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