Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
185/75r15 vs 165/80r15 Tire Comparison Side By Side
  185/75-15 165/80-15 Difference
Diameter inches (mm) 25.93 (658.5) 25.39 (645) -0.53 (-13.5) -2.1%
Width inches (mm) 7.28 (185) 6.5 (165) -0.79 (-20) -10.8%
Circum. inches (mm) 81.45 (2068.74) 79.78 (2026.33) -1.67 (-42.41) -2.1%
Sidewall Height inches (mm) 5.46 (138.75) 5.2 (132) -0.27 (-6.75) -4.9%
Revolutions per mile (km) 777.93 (483.39) 794.22 (493.5) 16.28 (10.12) 2.1%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.59 mph (31.53 km/h)
25 mph (40.23 km/h)24.49 mph (39.41 km/h)
30 mph (48.28 km/h)29.38 mph (47.29 km/h)
35 mph (56.33 km/h)34.28 mph (55.17 km/h)
40 mph (64.37 km/h)39.18 mph (63.05 km/h)
45 mph (72.42 km/h)44.08 mph (70.94 km/h)
50 mph (80.47 km/h)48.97 mph (78.82 km/h)
55 mph (88.51 km/h)53.87 mph (86.7 km/h)
60 mph (96.56 km/h)58.77 mph (94.58 km/h)
65 mph (104.61 km/h)63.67 mph (102.46 km/h)
70 mph (112.65 km/h)68.56 mph (110.34 km/h)
75 mph (120.7 km/h)73.46 mph (118.23 km/h)
80 mph (128.75 km/h)78.36 mph (126.11 km/h)
85 mph (136.79 km/h)83.26 mph (133.99 km/h)
90 mph (144.84 km/h)88.15 mph (141.87 km/h)
95 mph (152.89 km/h)93.05 mph (149.75 km/h)
100 mph (160.93 km/h)97.95 mph (157.64 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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