Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
185/50r15 vs 165/50r15 Tire Comparison Side By Side
  185/50-15 165/50-15 Difference
Diameter inches (mm) 22.28 (566) 21.5 (546) -0.79 (-20) -3.5%
Width inches (mm) 7.28 (185) 6.5 (165) -0.79 (-20) -10.8%
Circum. inches (mm) 70.01 (1778.14) 67.53 (1715.31) -2.47 (-62.83) -3.5%
Sidewall Height inches (mm) 3.64 (92.5) 3.25 (82.5) -0.39 (-10) -10.8%
Revolutions per mile (km) 905.07 (562.38) 938.22 (582.98) 33.15 (20.6) 3.7%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.29 mph (31.05 km/h)
25 mph (40.23 km/h)24.12 mph (38.81 km/h)
30 mph (48.28 km/h)28.94 mph (46.57 km/h)
35 mph (56.33 km/h)33.76 mph (54.34 km/h)
40 mph (64.37 km/h)38.59 mph (62.1 km/h)
45 mph (72.42 km/h)43.41 mph (69.86 km/h)
50 mph (80.47 km/h)48.23 mph (77.62 km/h)
55 mph (88.51 km/h)53.06 mph (85.39 km/h)
60 mph (96.56 km/h)57.88 mph (93.15 km/h)
65 mph (104.61 km/h)62.7 mph (100.91 km/h)
70 mph (112.65 km/h)67.53 mph (108.67 km/h)
75 mph (120.7 km/h)72.35 mph (116.44 km/h)
80 mph (128.75 km/h)77.17 mph (124.2 km/h)
85 mph (136.79 km/h)82 mph (131.96 km/h)
90 mph (144.84 km/h)86.82 mph (139.72 km/h)
95 mph (152.89 km/h)91.64 mph (147.49 km/h)
100 mph (160.93 km/h)96.47 mph (155.25 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
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
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