Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
155/70r13 vs 185/50r15 Tire Comparison Side By Side
  155/70-13 185/50-15 Difference
Diameter inches (mm) 21.54 (547.2) 22.28 (566) 0.74 (18.8) 3.4%
Width inches (mm) 6.1 (155) 7.28 (185) 1.18 (30) 19.4%
Circum. inches (mm) 67.68 (1719.08) 70.01 (1778.14) 2.33 (59.06) 3.4%
Sidewall Height inches (mm) 4.27 (108.5) 3.64 (92.5) -0.63 (-16) -14.7%
Revolutions per mile (km) 936.17 (581.71) 905.07 (562.38) -31.1 (-19.32) -3.3%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.69 mph (33.29 km/h)
25 mph (40.23 km/h)25.86 mph (41.62 km/h)
30 mph (48.28 km/h)31.03 mph (49.94 km/h)
35 mph (56.33 km/h)36.2 mph (58.26 km/h)
40 mph (64.37 km/h)41.37 mph (66.59 km/h)
45 mph (72.42 km/h)46.55 mph (74.91 km/h)
50 mph (80.47 km/h)51.72 mph (83.23 km/h)
55 mph (88.51 km/h)56.89 mph (91.56 km/h)
60 mph (96.56 km/h)62.06 mph (99.88 km/h)
65 mph (104.61 km/h)67.23 mph (108.2 km/h)
70 mph (112.65 km/h)72.4 mph (116.52 km/h)
75 mph (120.7 km/h)77.58 mph (124.85 km/h)
80 mph (128.75 km/h)82.75 mph (133.17 km/h)
85 mph (136.79 km/h)87.92 mph (141.49 km/h)
90 mph (144.84 km/h)93.09 mph (149.82 km/h)
95 mph (152.89 km/h)98.26 mph (158.14 km/h)
100 mph (160.93 km/h)103.44 mph (166.46 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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