Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
165/90r18 vs 155/80r17 Tire Comparison Side By Side
  165/90-18 155/80-17 Difference
Diameter inches (mm) 29.69 (754.2) 26.76 (679.8) -2.93 (-74.4) -9.9%
Width inches (mm) 6.5 (165) 6.1 (155) -0.39 (-10) -6.1%
Circum. inches (mm) 93.28 (2369.39) 84.08 (2135.65) -9.2 (-233.73) -9.9%
Sidewall Height inches (mm) 5.85 (148.5) 4.88 (124) -0.96 (-24.5) -16.5%
Revolutions per mile (km) 679.22 (422.05) 753.56 (468.24) 74.34 (46.19) 10.9%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)18.03 mph (29.01 km/h)
25 mph (40.23 km/h)22.53 mph (36.26 km/h)
30 mph (48.28 km/h)27.04 mph (43.52 km/h)
35 mph (56.33 km/h)31.55 mph (50.77 km/h)
40 mph (64.37 km/h)36.05 mph (58.02 km/h)
45 mph (72.42 km/h)40.56 mph (65.28 km/h)
50 mph (80.47 km/h)45.07 mph (72.53 km/h)
55 mph (88.51 km/h)49.57 mph (79.78 km/h)
60 mph (96.56 km/h)54.08 mph (87.04 km/h)
65 mph (104.61 km/h)58.59 mph (94.29 km/h)
70 mph (112.65 km/h)63.09 mph (101.54 km/h)
75 mph (120.7 km/h)67.6 mph (108.79 km/h)
80 mph (128.75 km/h)72.11 mph (116.05 km/h)
85 mph (136.79 km/h)76.61 mph (123.3 km/h)
90 mph (144.84 km/h)81.12 mph (130.55 km/h)
95 mph (152.89 km/h)85.63 mph (137.81 km/h)
100 mph (160.93 km/h)90.14 mph (145.06 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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