Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
180/70r15 vs 180/60r15 Tire Comparison Side By Side
  180/70-15 180/60-15 Difference
Diameter inches (mm) 24.92 (633) 23.5 (597) -1.42 (-36) -5.7%
Width inches (mm) 7.09 (180) 7.09 (180) 0 (0) 0%
Circum. inches (mm) 78.29 (1988.63) 73.84 (1875.53) -4.45 (-113.1) -5.7%
Sidewall Height inches (mm) 4.96 (126) 4.25 (108) -0.71 (-18) -14.3%
Revolutions per mile (km) 809.27 (502.86) 858.07 (533.18) 48.8 (30.32) 6%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)18.86 mph (30.36 km/h)
25 mph (40.23 km/h)23.58 mph (37.95 km/h)
30 mph (48.28 km/h)28.29 mph (45.53 km/h)
35 mph (56.33 km/h)33.01 mph (53.12 km/h)
40 mph (64.37 km/h)37.73 mph (60.71 km/h)
45 mph (72.42 km/h)42.44 mph (68.3 km/h)
50 mph (80.47 km/h)47.16 mph (75.89 km/h)
55 mph (88.51 km/h)51.87 mph (83.48 km/h)
60 mph (96.56 km/h)56.59 mph (91.07 km/h)
65 mph (104.61 km/h)61.3 mph (98.66 km/h)
70 mph (112.65 km/h)66.02 mph (106.25 km/h)
75 mph (120.7 km/h)70.73 mph (113.84 km/h)
80 mph (128.75 km/h)75.45 mph (121.43 km/h)
85 mph (136.79 km/h)80.17 mph (129.01 km/h)
90 mph (144.84 km/h)84.88 mph (136.6 km/h)
95 mph (152.89 km/h)89.6 mph (144.19 km/h)
100 mph (160.93 km/h)94.31 mph (151.78 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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