Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
185/80r15 vs 185/85r15 Tire Comparison Side By Side
  185/80-15 185/85-15 Difference
Diameter inches (mm) 26.65 (677) 27.38 (695.5) 0.73 (18.5) 2.7%
Width inches (mm) 7.28 (185) 7.28 (185) 0 (0) 0%
Circum. inches (mm) 83.73 (2126.86) 86.02 (2184.98) 2.29 (58.12) 2.7%
Sidewall Height inches (mm) 5.83 (148) 6.19 (157.25) 0.36 (9.25) 6.3%
Revolutions per mile (km) 756.68 (470.18) 736.55 (457.67) -20.13 (-12.51) -2.7%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.55 mph (33.07 km/h)
25 mph (40.23 km/h)25.68 mph (41.33 km/h)
30 mph (48.28 km/h)30.82 mph (49.6 km/h)
35 mph (56.33 km/h)35.96 mph (57.87 km/h)
40 mph (64.37 km/h)41.09 mph (66.13 km/h)
45 mph (72.42 km/h)46.23 mph (74.4 km/h)
50 mph (80.47 km/h)51.37 mph (82.67 km/h)
55 mph (88.51 km/h)56.5 mph (90.93 km/h)
60 mph (96.56 km/h)61.64 mph (99.2 km/h)
65 mph (104.61 km/h)66.78 mph (107.47 km/h)
70 mph (112.65 km/h)71.91 mph (115.73 km/h)
75 mph (120.7 km/h)77.05 mph (124 km/h)
80 mph (128.75 km/h)82.19 mph (132.27 km/h)
85 mph (136.79 km/h)87.32 mph (140.53 km/h)
90 mph (144.84 km/h)92.46 mph (148.8 km/h)
95 mph (152.89 km/h)97.6 mph (157.07 km/h)
100 mph (160.93 km/h)102.73 mph (165.33 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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