Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
255/70r15 vs 30/9.5r15 Tire Comparison Side By Side
  255/70-15 30/9.5-15 Difference
Diameter inches (mm) 29.06 (738) 29.99 (761.78) 0.94 (23.78) 3.2%
Width inches (mm) 10.04 (255) 9.49 (241) -0.55 (-14) -5.5%
Circum. inches (mm) 91.28 (2318.5) 94.22 (2393.2) 2.94 (74.71) 3.2%
Sidewall Height inches (mm) 7.03 (178.5) 7.5 (190.39) 0.47 (11.89) 6.7%
Revolutions per mile (km) 694.13 (431.31) 672.46 (417.85) -21.67 (-13.46) -3.1%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.64 mph (33.22 km/h)
25 mph (40.23 km/h)25.81 mph (41.53 km/h)
30 mph (48.28 km/h)30.97 mph (49.84 km/h)
35 mph (56.33 km/h)36.13 mph (58.14 km/h)
40 mph (64.37 km/h)41.29 mph (66.45 km/h)
45 mph (72.42 km/h)46.45 mph (74.75 km/h)
50 mph (80.47 km/h)51.61 mph (83.06 km/h)
55 mph (88.51 km/h)56.77 mph (91.37 km/h)
60 mph (96.56 km/h)61.93 mph (99.67 km/h)
65 mph (104.61 km/h)67.09 mph (107.98 km/h)
70 mph (112.65 km/h)72.26 mph (116.28 km/h)
75 mph (120.7 km/h)77.42 mph (124.59 km/h)
80 mph (128.75 km/h)82.58 mph (132.9 km/h)
85 mph (136.79 km/h)87.74 mph (141.2 km/h)
90 mph (144.84 km/h)92.9 mph (149.51 km/h)
95 mph (152.89 km/h)98.06 mph (157.81 km/h)
100 mph (160.93 km/h)103.22 mph (166.12 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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