Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
245/40r18 vs 235/40r18 Tire Comparison Side By Side
  245/40-18 235/40-18 Difference
Diameter inches (mm) 25.72 (653.2) 25.4 (645.2) -0.31 (-8) -1.2%
Width inches (mm) 9.65 (245) 9.25 (235) -0.39 (-10) -4.1%
Circum. inches (mm) 80.79 (2052.09) 79.8 (2026.96) -0.99 (-25.13) -1.2%
Sidewall Height inches (mm) 3.86 (98) 3.7 (94) -0.16 (-4) -4.1%
Revolutions per mile (km) 784.25 (487.31) 793.97 (493.35) 9.72 (6.04) 1.2%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.76 mph (31.79 km/h)
25 mph (40.23 km/h)24.69 mph (39.74 km/h)
30 mph (48.28 km/h)29.63 mph (47.69 km/h)
35 mph (56.33 km/h)34.57 mph (55.64 km/h)
40 mph (64.37 km/h)39.51 mph (63.59 km/h)
45 mph (72.42 km/h)44.45 mph (71.53 km/h)
50 mph (80.47 km/h)49.39 mph (79.48 km/h)
55 mph (88.51 km/h)54.33 mph (87.43 km/h)
60 mph (96.56 km/h)59.27 mph (95.38 km/h)
65 mph (104.61 km/h)64.2 mph (103.33 km/h)
70 mph (112.65 km/h)69.14 mph (111.27 km/h)
75 mph (120.7 km/h)74.08 mph (119.22 km/h)
80 mph (128.75 km/h)79.02 mph (127.17 km/h)
85 mph (136.79 km/h)83.96 mph (135.12 km/h)
90 mph (144.84 km/h)88.9 mph (143.07 km/h)
95 mph (152.89 km/h)93.84 mph (151.02 km/h)
100 mph (160.93 km/h)98.78 mph (158.96 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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