Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
275/50r21 vs 275/70r18 Tire Comparison Side By Side
  275/50-21 275/70-18 Difference
Diameter inches (mm) 31.83 (808.4) 33.16 (842.2) 1.33 (33.8) 4.2%
Width inches (mm) 10.83 (275) 10.83 (275) 0 (0) 0%
Circum. inches (mm) 99.99 (2539.66) 104.17 (2645.85) 4.18 (106.19) 4.2%
Sidewall Height inches (mm) 5.41 (137.5) 7.58 (192.5) 2.17 (55) 40%
Revolutions per mile (km) 633.68 (393.75) 608.25 (377.95) -25.43 (-15.8) -4%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.84 mph (33.53 km/h)
25 mph (40.23 km/h)26.05 mph (41.92 km/h)
30 mph (48.28 km/h)31.25 mph (50.3 km/h)
35 mph (56.33 km/h)36.46 mph (58.68 km/h)
40 mph (64.37 km/h)41.67 mph (67.07 km/h)
45 mph (72.42 km/h)46.88 mph (75.45 km/h)
50 mph (80.47 km/h)52.09 mph (83.83 km/h)
55 mph (88.51 km/h)57.3 mph (92.21 km/h)
60 mph (96.56 km/h)62.51 mph (100.6 km/h)
65 mph (104.61 km/h)67.72 mph (108.98 km/h)
70 mph (112.65 km/h)72.93 mph (117.36 km/h)
75 mph (120.7 km/h)78.14 mph (125.75 km/h)
80 mph (128.75 km/h)83.34 mph (134.13 km/h)
85 mph (136.79 km/h)88.55 mph (142.51 km/h)
90 mph (144.84 km/h)93.76 mph (150.9 km/h)
95 mph (152.89 km/h)98.97 mph (159.28 km/h)
100 mph (160.93 km/h)104.18 mph (167.66 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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