Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
225/45r18 vs 245/40r18 Tire Comparison Side By Side
  225/45-18 245/40-18 Difference
Diameter inches (mm) 25.97 (659.7) 25.72 (653.2) -0.26 (-6.5) -1%
Width inches (mm) 8.86 (225) 9.65 (245) 0.79 (20) 8.9%
Circum. inches (mm) 81.59 (2072.51) 80.79 (2052.09) -0.8 (-20.42) -1%
Sidewall Height inches (mm) 3.99 (101.25) 3.86 (98) -0.13 (-3.25) -3.2%
Revolutions per mile (km) 776.52 (482.51) 784.25 (487.31) 7.73 (4.8) 1%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.8 mph (31.87 km/h)
25 mph (40.23 km/h)24.75 mph (39.84 km/h)
30 mph (48.28 km/h)29.7 mph (47.8 km/h)
35 mph (56.33 km/h)34.66 mph (55.77 km/h)
40 mph (64.37 km/h)39.61 mph (63.74 km/h)
45 mph (72.42 km/h)44.56 mph (71.71 km/h)
50 mph (80.47 km/h)49.51 mph (79.67 km/h)
55 mph (88.51 km/h)54.46 mph (87.64 km/h)
60 mph (96.56 km/h)59.41 mph (95.61 km/h)
65 mph (104.61 km/h)64.36 mph (103.58 km/h)
70 mph (112.65 km/h)69.31 mph (111.54 km/h)
75 mph (120.7 km/h)74.26 mph (119.51 km/h)
80 mph (128.75 km/h)79.21 mph (127.48 km/h)
85 mph (136.79 km/h)84.16 mph (135.45 km/h)
90 mph (144.84 km/h)89.11 mph (143.41 km/h)
95 mph (152.89 km/h)94.06 mph (151.38 km/h)
100 mph (160.93 km/h)99.01 mph (159.35 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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