Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
185/65r18 vs 165/70r16 Tire Comparison Side By Side
  185/65-18 165/70-16 Difference
Diameter inches (mm) 27.47 (697.7) 25.09 (637.4) -2.37 (-60.3) -8.6%
Width inches (mm) 7.28 (185) 6.5 (165) -0.79 (-20) -10.8%
Circum. inches (mm) 86.29 (2191.89) 78.84 (2002.45) -7.46 (-189.44) -8.6%
Sidewall Height inches (mm) 4.73 (120.25) 4.55 (115.5) -0.19 (-4.75) -4%
Revolutions per mile (km) 734.23 (456.23) 803.69 (499.39) 69.46 (43.16) 9.5%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)18.27 mph (29.41 km/h)
25 mph (40.23 km/h)22.84 mph (36.76 km/h)
30 mph (48.28 km/h)27.41 mph (44.11 km/h)
35 mph (56.33 km/h)31.98 mph (51.46 km/h)
40 mph (64.37 km/h)36.54 mph (58.81 km/h)
45 mph (72.42 km/h)41.11 mph (66.16 km/h)
50 mph (80.47 km/h)45.68 mph (73.51 km/h)
55 mph (88.51 km/h)50.25 mph (80.86 km/h)
60 mph (96.56 km/h)54.81 mph (88.22 km/h)
65 mph (104.61 km/h)59.38 mph (95.57 km/h)
70 mph (112.65 km/h)63.95 mph (102.92 km/h)
75 mph (120.7 km/h)68.52 mph (110.27 km/h)
80 mph (128.75 km/h)73.09 mph (117.62 km/h)
85 mph (136.79 km/h)77.65 mph (124.97 km/h)
90 mph (144.84 km/h)82.22 mph (132.32 km/h)
95 mph (152.89 km/h)86.79 mph (139.67 km/h)
100 mph (160.93 km/h)91.36 mph (147.03 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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