Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
180/60r15 vs 185/60r15 Tire Comparison Side By Side
  180/60-15 185/60-15 Difference
Diameter inches (mm) 23.5 (597) 23.74 (603) 0.24 (6) 1%
Width inches (mm) 7.09 (180) 7.28 (185) 0.2 (5) 2.8%
Circum. inches (mm) 73.84 (1875.53) 74.58 (1894.38) 0.74 (18.85) 1%
Sidewall Height inches (mm) 4.25 (108) 4.37 (111) 0.12 (3) 2.8%
Revolutions per mile (km) 858.07 (533.18) 849.54 (527.88) -8.54 (-5.31) -1%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.2 mph (32.51 km/h)
25 mph (40.23 km/h)25.25 mph (40.64 km/h)
30 mph (48.28 km/h)30.3 mph (48.77 km/h)
35 mph (56.33 km/h)35.35 mph (56.89 km/h)
40 mph (64.37 km/h)40.4 mph (65.02 km/h)
45 mph (72.42 km/h)45.45 mph (73.15 km/h)
50 mph (80.47 km/h)50.5 mph (81.28 km/h)
55 mph (88.51 km/h)55.55 mph (89.4 km/h)
60 mph (96.56 km/h)60.6 mph (97.53 km/h)
65 mph (104.61 km/h)65.65 mph (105.66 km/h)
70 mph (112.65 km/h)70.7 mph (113.79 km/h)
75 mph (120.7 km/h)75.75 mph (121.91 km/h)
80 mph (128.75 km/h)80.8 mph (130.04 km/h)
85 mph (136.79 km/h)85.85 mph (138.17 km/h)
90 mph (144.84 km/h)90.9 mph (146.3 km/h)
95 mph (152.89 km/h)95.95 mph (154.42 km/h)
100 mph (160.93 km/h)101.01 mph (162.55 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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