Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
325/80r15 vs 310/85r16 Tire Comparison Side By Side
  325/80-15 310/85-16 Difference
Diameter inches (mm) 35.47 (901) 36.75 (933.4) 1.28 (32.4) 3.6%
Width inches (mm) 12.8 (325) 12.2 (310) -0.59 (-15) -4.6%
Circum. inches (mm) 111.44 (2830.57) 115.45 (2932.36) 4.01 (101.79) 3.6%
Sidewall Height inches (mm) 10.24 (260) 10.37 (263.5) 0.14 (3.5) 1.3%
Revolutions per mile (km) 568.56 (353.28) 548.82 (341.02) -19.74 (-12.26) -3.5%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.72 mph (33.34 km/h)
25 mph (40.23 km/h)25.9 mph (41.68 km/h)
30 mph (48.28 km/h)31.08 mph (50.02 km/h)
35 mph (56.33 km/h)36.26 mph (58.35 km/h)
40 mph (64.37 km/h)41.44 mph (66.69 km/h)
45 mph (72.42 km/h)46.62 mph (75.02 km/h)
50 mph (80.47 km/h)51.8 mph (83.36 km/h)
55 mph (88.51 km/h)56.98 mph (91.7 km/h)
60 mph (96.56 km/h)62.16 mph (100.03 km/h)
65 mph (104.61 km/h)67.34 mph (108.37 km/h)
70 mph (112.65 km/h)72.52 mph (116.71 km/h)
75 mph (120.7 km/h)77.7 mph (125.04 km/h)
80 mph (128.75 km/h)82.88 mph (133.38 km/h)
85 mph (136.79 km/h)88.06 mph (141.71 km/h)
90 mph (144.84 km/h)93.24 mph (150.05 km/h)
95 mph (152.89 km/h)98.42 mph (158.39 km/h)
100 mph (160.93 km/h)103.6 mph (166.72 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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