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 165/80r17 Tire Comparison Side By Side
  165/90-18 165/80-17 Difference
Diameter inches (mm) 29.69 (754.2) 27.39 (695.8) -2.3 (-58.4) -7.7%
Width inches (mm) 6.5 (165) 6.5 (165) 0 (0) 0%
Circum. inches (mm) 93.28 (2369.39) 86.06 (2185.92) -7.22 (-183.47) -7.7%
Sidewall Height inches (mm) 5.85 (148.5) 5.2 (132) -0.65 (-16.5) -11.1%
Revolutions per mile (km) 679.22 (422.05) 736.23 (457.47) 57.01 (35.42) 8.4%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)18.45 mph (29.69 km/h)
25 mph (40.23 km/h)23.06 mph (37.12 km/h)
30 mph (48.28 km/h)27.68 mph (44.54 km/h)
35 mph (56.33 km/h)32.29 mph (51.97 km/h)
40 mph (64.37 km/h)36.9 mph (59.39 km/h)
45 mph (72.42 km/h)41.52 mph (66.81 km/h)
50 mph (80.47 km/h)46.13 mph (74.24 km/h)
55 mph (88.51 km/h)50.74 mph (81.66 km/h)
60 mph (96.56 km/h)55.35 mph (89.08 km/h)
65 mph (104.61 km/h)59.97 mph (96.51 km/h)
70 mph (112.65 km/h)64.58 mph (103.93 km/h)
75 mph (120.7 km/h)69.19 mph (111.35 km/h)
80 mph (128.75 km/h)73.81 mph (118.78 km/h)
85 mph (136.79 km/h)78.42 mph (126.2 km/h)
90 mph (144.84 km/h)83.03 mph (133.63 km/h)
95 mph (152.89 km/h)87.64 mph (141.05 km/h)
100 mph (160.93 km/h)92.26 mph (148.47 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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