Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
145/60r20 vs 245/40r20 Tire Comparison Side By Side
  145/60-20 245/40-20 Difference
Diameter inches (mm) 26.85 (682) 27.72 (704) 0.87 (22) 3.2%
Width inches (mm) 5.71 (145) 9.65 (245) 3.94 (100) 69%
Circum. inches (mm) 84.35 (2142.57) 87.07 (2211.68) 2.72 (69.12) 3.2%
Sidewall Height inches (mm) 3.43 (87) 3.86 (98) 0.43 (11) 12.6%
Revolutions per mile (km) 751.13 (466.73) 727.66 (452.14) -23.47 (-14.59) -3.1%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.65 mph (33.23 km/h)
25 mph (40.23 km/h)25.81 mph (41.53 km/h)
30 mph (48.28 km/h)30.97 mph (49.84 km/h)
35 mph (56.33 km/h)36.13 mph (58.14 km/h)
40 mph (64.37 km/h)41.29 mph (66.45 km/h)
45 mph (72.42 km/h)46.45 mph (74.76 km/h)
50 mph (80.47 km/h)51.61 mph (83.06 km/h)
55 mph (88.51 km/h)56.77 mph (91.37 km/h)
60 mph (96.56 km/h)61.94 mph (99.68 km/h)
65 mph (104.61 km/h)67.1 mph (107.98 km/h)
70 mph (112.65 km/h)72.26 mph (116.29 km/h)
75 mph (120.7 km/h)77.42 mph (124.59 km/h)
80 mph (128.75 km/h)82.58 mph (132.9 km/h)
85 mph (136.79 km/h)87.74 mph (141.21 km/h)
90 mph (144.84 km/h)92.9 mph (149.51 km/h)
95 mph (152.89 km/h)98.06 mph (157.82 km/h)
100 mph (160.93 km/h)103.23 mph (166.13 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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