Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
255/40r20 vs 245/40r20 Tire Comparison Side By Side
  255/40-20 245/40-20 Difference
Diameter inches (mm) 28.03 (712) 27.72 (704) -0.31 (-8) -1.1%
Width inches (mm) 10.04 (255) 9.65 (245) -0.39 (-10) -3.9%
Circum. inches (mm) 88.06 (2236.81) 87.07 (2211.68) -0.99 (-25.13) -1.1%
Sidewall Height inches (mm) 4.02 (102) 3.86 (98) -0.16 (-4) -3.9%
Revolutions per mile (km) 719.48 (447.06) 727.66 (452.14) 8.18 (5.08) 1.1%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.78 mph (31.83 km/h)
25 mph (40.23 km/h)24.72 mph (39.78 km/h)
30 mph (48.28 km/h)29.66 mph (47.74 km/h)
35 mph (56.33 km/h)34.61 mph (55.69 km/h)
40 mph (64.37 km/h)39.55 mph (63.65 km/h)
45 mph (72.42 km/h)44.49 mph (71.61 km/h)
50 mph (80.47 km/h)49.44 mph (79.56 km/h)
55 mph (88.51 km/h)54.38 mph (87.52 km/h)
60 mph (96.56 km/h)59.33 mph (95.48 km/h)
65 mph (104.61 km/h)64.27 mph (103.43 km/h)
70 mph (112.65 km/h)69.21 mph (111.39 km/h)
75 mph (120.7 km/h)74.16 mph (119.34 km/h)
80 mph (128.75 km/h)79.1 mph (127.3 km/h)
85 mph (136.79 km/h)84.04 mph (135.26 km/h)
90 mph (144.84 km/h)88.99 mph (143.21 km/h)
95 mph (152.89 km/h)93.93 mph (151.17 km/h)
100 mph (160.93 km/h)98.88 mph (159.13 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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