Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
275/40r21 vs 250/50r20 Tire Comparison Side By Side
  275/40-21 250/50-20 Difference
Diameter inches (mm) 29.66 (753.4) 29.84 (758) 0.18 (4.6) 0.6%
Width inches (mm) 10.83 (275) 9.84 (250) -0.98 (-25) -9.1%
Circum. inches (mm) 93.18 (2366.88) 93.75 (2381.33) 0.57 (14.45) 0.6%
Sidewall Height inches (mm) 4.33 (110) 4.92 (125) 0.59 (15) 13.6%
Revolutions per mile (km) 679.94 (422.5) 675.82 (419.93) -4.13 (-2.56) -0.6%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.12 mph (32.38 km/h)
25 mph (40.23 km/h)25.15 mph (40.48 km/h)
30 mph (48.28 km/h)30.18 mph (48.58 km/h)
35 mph (56.33 km/h)35.21 mph (56.67 km/h)
40 mph (64.37 km/h)40.24 mph (64.77 km/h)
45 mph (72.42 km/h)45.27 mph (72.86 km/h)
50 mph (80.47 km/h)50.31 mph (80.96 km/h)
55 mph (88.51 km/h)55.34 mph (89.05 km/h)
60 mph (96.56 km/h)60.37 mph (97.15 km/h)
65 mph (104.61 km/h)65.4 mph (105.25 km/h)
70 mph (112.65 km/h)70.43 mph (113.34 km/h)
75 mph (120.7 km/h)75.46 mph (121.44 km/h)
80 mph (128.75 km/h)80.49 mph (129.53 km/h)
85 mph (136.79 km/h)85.52 mph (137.63 km/h)
90 mph (144.84 km/h)90.55 mph (145.73 km/h)
95 mph (152.89 km/h)95.58 mph (153.82 km/h)
100 mph (160.93 km/h)100.61 mph (161.92 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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