Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
255/50r21 vs 275/50r21 Tire Comparison Side By Side
  255/50-21 275/50-21 Difference
Diameter inches (mm) 31.04 (788.4) 31.83 (808.4) 0.79 (20) 2.5%
Width inches (mm) 10.04 (255) 10.83 (275) 0.79 (20) 7.8%
Circum. inches (mm) 97.51 (2476.83) 99.99 (2539.66) 2.47 (62.83) 2.5%
Sidewall Height inches (mm) 5.02 (127.5) 5.41 (137.5) 0.39 (10) 7.8%
Revolutions per mile (km) 649.76 (403.74) 633.68 (393.75) -16.08 (-9.99) -2.5%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.51 mph (33 km/h)
25 mph (40.23 km/h)25.63 mph (41.25 km/h)
30 mph (48.28 km/h)30.76 mph (49.51 km/h)
35 mph (56.33 km/h)35.89 mph (57.76 km/h)
40 mph (64.37 km/h)41.01 mph (66.01 km/h)
45 mph (72.42 km/h)46.14 mph (74.26 km/h)
50 mph (80.47 km/h)51.27 mph (82.51 km/h)
55 mph (88.51 km/h)56.4 mph (90.76 km/h)
60 mph (96.56 km/h)61.52 mph (99.01 km/h)
65 mph (104.61 km/h)66.65 mph (107.26 km/h)
70 mph (112.65 km/h)71.78 mph (115.51 km/h)
75 mph (120.7 km/h)76.9 mph (123.76 km/h)
80 mph (128.75 km/h)82.03 mph (132.01 km/h)
85 mph (136.79 km/h)87.16 mph (140.26 km/h)
90 mph (144.84 km/h)92.28 mph (148.52 km/h)
95 mph (152.89 km/h)97.41 mph (156.77 km/h)
100 mph (160.93 km/h)102.54 mph (165.02 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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