Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
120/70r18 vs 130/80r18 Tire Comparison Side By Side
  120/70-18 130/80-18 Difference
Diameter inches (mm) 24.61 (625.2) 26.19 (665.2) 1.57 (40) 6.4%
Width inches (mm) 4.72 (120) 5.12 (130) 0.39 (10) 8.3%
Circum. inches (mm) 77.33 (1964.12) 82.28 (2089.79) 4.95 (125.66) 6.4%
Sidewall Height inches (mm) 3.31 (84) 4.09 (104) 0.79 (20) 23.8%
Revolutions per mile (km) 819.37 (509.13) 770.1 (478.52) -49.27 (-30.62) -6%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)21.28 mph (34.25 km/h)
25 mph (40.23 km/h)26.6 mph (42.81 km/h)
30 mph (48.28 km/h)31.92 mph (51.37 km/h)
35 mph (56.33 km/h)37.24 mph (59.93 km/h)
40 mph (64.37 km/h)42.56 mph (68.49 km/h)
45 mph (72.42 km/h)47.88 mph (77.05 km/h)
50 mph (80.47 km/h)53.2 mph (85.62 km/h)
55 mph (88.51 km/h)58.52 mph (94.18 km/h)
60 mph (96.56 km/h)63.84 mph (102.74 km/h)
65 mph (104.61 km/h)69.16 mph (111.3 km/h)
70 mph (112.65 km/h)74.48 mph (119.86 km/h)
75 mph (120.7 km/h)79.8 mph (128.42 km/h)
80 mph (128.75 km/h)85.12 mph (136.98 km/h)
85 mph (136.79 km/h)90.44 mph (145.55 km/h)
90 mph (144.84 km/h)95.76 mph (154.11 km/h)
95 mph (152.89 km/h)101.08 mph (162.67 km/h)
100 mph (160.93 km/h)106.4 mph (171.23 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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