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 285/40r20 Tire Comparison Side By Side
  255/40-20 285/40-20 Difference
Diameter inches (mm) 28.03 (712) 28.98 (736) 0.94 (24) 3.4%
Width inches (mm) 10.04 (255) 11.22 (285) 1.18 (30) 11.8%
Circum. inches (mm) 88.06 (2236.81) 91.03 (2312.21) 2.97 (75.4) 3.4%
Sidewall Height inches (mm) 4.02 (102) 4.49 (114) 0.47 (12) 11.8%
Revolutions per mile (km) 719.48 (447.06) 696.02 (432.49) -23.46 (-14.58) -3.3%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.67 mph (33.27 km/h)
25 mph (40.23 km/h)25.84 mph (41.59 km/h)
30 mph (48.28 km/h)31.01 mph (49.91 km/h)
35 mph (56.33 km/h)36.18 mph (58.23 km/h)
40 mph (64.37 km/h)41.35 mph (66.54 km/h)
45 mph (72.42 km/h)46.52 mph (74.86 km/h)
50 mph (80.47 km/h)51.69 mph (83.18 km/h)
55 mph (88.51 km/h)56.85 mph (91.5 km/h)
60 mph (96.56 km/h)62.02 mph (99.82 km/h)
65 mph (104.61 km/h)67.19 mph (108.13 km/h)
70 mph (112.65 km/h)72.36 mph (116.45 km/h)
75 mph (120.7 km/h)77.53 mph (124.77 km/h)
80 mph (128.75 km/h)82.7 mph (133.09 km/h)
85 mph (136.79 km/h)87.87 mph (141.41 km/h)
90 mph (144.84 km/h)93.03 mph (149.72 km/h)
95 mph (152.89 km/h)98.2 mph (158.04 km/h)
100 mph (160.93 km/h)103.37 mph (166.36 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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