Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
185/55r15 vs 185/65r15 Tire Comparison Side By Side
  185/55-15 185/65-15 Difference
Diameter inches (mm) 23.01 (584.5) 24.47 (621.5) 1.46 (37) 6.3%
Width inches (mm) 7.28 (185) 7.28 (185) 0 (0) 0%
Circum. inches (mm) 72.29 (1836.26) 76.87 (1952.5) 4.58 (116.24) 6.3%
Sidewall Height inches (mm) 4.01 (101.75) 4.73 (120.25) 0.73 (18.5) 18.2%
Revolutions per mile (km) 876.42 (544.58) 824.25 (512.16) -52.18 (-32.42) -6%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)21.27 mph (34.22 km/h)
25 mph (40.23 km/h)26.58 mph (42.78 km/h)
30 mph (48.28 km/h)31.9 mph (51.34 km/h)
35 mph (56.33 km/h)37.22 mph (59.89 km/h)
40 mph (64.37 km/h)42.53 mph (68.45 km/h)
45 mph (72.42 km/h)47.85 mph (77 km/h)
50 mph (80.47 km/h)53.17 mph (85.56 km/h)
55 mph (88.51 km/h)58.48 mph (94.12 km/h)
60 mph (96.56 km/h)63.8 mph (102.67 km/h)
65 mph (104.61 km/h)69.11 mph (111.23 km/h)
70 mph (112.65 km/h)74.43 mph (119.79 km/h)
75 mph (120.7 km/h)79.75 mph (128.34 km/h)
80 mph (128.75 km/h)85.06 mph (136.9 km/h)
85 mph (136.79 km/h)90.38 mph (145.45 km/h)
90 mph (144.84 km/h)95.7 mph (154.01 km/h)
95 mph (152.89 km/h)101.01 mph (162.57 km/h)
100 mph (160.93 km/h)106.33 mph (171.12 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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