Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
235/75r15 vs 245/40r18 Tire Comparison Side By Side
  235/75-15 245/40-18 Difference
Diameter inches (mm) 28.88 (733.5) 25.72 (653.2) -3.16 (-80.3) -10.9%
Width inches (mm) 9.25 (235) 9.65 (245) 0.39 (10) 4.3%
Circum. inches (mm) 90.72 (2304.36) 80.79 (2052.09) -9.93 (-252.27) -10.9%
Sidewall Height inches (mm) 6.94 (176.25) 3.86 (98) -3.08 (-78.25) -44.4%
Revolutions per mile (km) 698.39 (433.96) 784.25 (487.31) 85.86 (53.35) 12.3%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)17.81 mph (28.66 km/h)
25 mph (40.23 km/h)22.26 mph (35.83 km/h)
30 mph (48.28 km/h)26.72 mph (42.99 km/h)
35 mph (56.33 km/h)31.17 mph (50.16 km/h)
40 mph (64.37 km/h)35.62 mph (57.33 km/h)
45 mph (72.42 km/h)40.07 mph (64.49 km/h)
50 mph (80.47 km/h)44.53 mph (71.66 km/h)
55 mph (88.51 km/h)48.98 mph (78.82 km/h)
60 mph (96.56 km/h)53.43 mph (85.99 km/h)
65 mph (104.61 km/h)57.88 mph (93.16 km/h)
70 mph (112.65 km/h)62.34 mph (100.32 km/h)
75 mph (120.7 km/h)66.79 mph (107.49 km/h)
80 mph (128.75 km/h)71.24 mph (114.65 km/h)
85 mph (136.79 km/h)75.69 mph (121.82 km/h)
90 mph (144.84 km/h)80.15 mph (128.98 km/h)
95 mph (152.89 km/h)84.6 mph (136.15 km/h)
100 mph (160.93 km/h)89.05 mph (143.32 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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