Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
265/40r18 vs 235/45r18 Tire Comparison Side By Side
  265/40-18 235/45-18 Difference
Diameter inches (mm) 26.35 (669.2) 26.33 (668.7) -0.02 (-0.5) -0.1%
Width inches (mm) 10.43 (265) 9.25 (235) -1.18 (-30) -11.3%
Circum. inches (mm) 82.77 (2102.35) 82.71 (2100.78) -0.06 (-1.57) -0.1%
Sidewall Height inches (mm) 4.17 (106) 4.16 (105.75) -0.01 (-0.25) -0.2%
Revolutions per mile (km) 765.5 (475.66) 766.07 (476.01) 0.57 (0.36) 0.1%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.99 mph (32.16 km/h)
25 mph (40.23 km/h)24.98 mph (40.2 km/h)
30 mph (48.28 km/h)29.98 mph (48.24 km/h)
35 mph (56.33 km/h)34.97 mph (56.29 km/h)
40 mph (64.37 km/h)39.97 mph (64.33 km/h)
45 mph (72.42 km/h)44.97 mph (72.37 km/h)
50 mph (80.47 km/h)49.96 mph (80.41 km/h)
55 mph (88.51 km/h)54.96 mph (88.45 km/h)
60 mph (96.56 km/h)59.96 mph (96.49 km/h)
65 mph (104.61 km/h)64.95 mph (104.53 km/h)
70 mph (112.65 km/h)69.95 mph (112.57 km/h)
75 mph (120.7 km/h)74.94 mph (120.61 km/h)
80 mph (128.75 km/h)79.94 mph (128.65 km/h)
85 mph (136.79 km/h)84.94 mph (136.69 km/h)
90 mph (144.84 km/h)89.93 mph (144.73 km/h)
95 mph (152.89 km/h)94.93 mph (152.77 km/h)
100 mph (160.93 km/h)99.93 mph (160.81 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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