Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
275/30r21 vs 265/40r20 Tire Comparison Side By Side
  275/30-21 265/40-20 Difference
Diameter inches (mm) 27.5 (698.4) 28.35 (720) 0.85 (21.6) 3.1%
Width inches (mm) 10.83 (275) 10.43 (265) -0.39 (-10) -3.6%
Circum. inches (mm) 86.38 (2194.09) 89.05 (2261.95) 2.67 (67.86) 3.1%
Sidewall Height inches (mm) 3.25 (82.5) 4.17 (106) 0.93 (23.5) 28.5%
Revolutions per mile (km) 733.49 (455.77) 711.49 (442.1) -22 (-13.67) -3%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.62 mph (33.18 km/h)
25 mph (40.23 km/h)25.77 mph (41.48 km/h)
30 mph (48.28 km/h)30.93 mph (49.77 km/h)
35 mph (56.33 km/h)36.08 mph (58.07 km/h)
40 mph (64.37 km/h)41.24 mph (66.36 km/h)
45 mph (72.42 km/h)46.39 mph (74.66 km/h)
50 mph (80.47 km/h)51.55 mph (82.96 km/h)
55 mph (88.51 km/h)56.7 mph (91.25 km/h)
60 mph (96.56 km/h)61.86 mph (99.55 km/h)
65 mph (104.61 km/h)67.01 mph (107.84 km/h)
70 mph (112.65 km/h)72.16 mph (116.14 km/h)
75 mph (120.7 km/h)77.32 mph (124.43 km/h)
80 mph (128.75 km/h)82.47 mph (132.73 km/h)
85 mph (136.79 km/h)87.63 mph (141.03 km/h)
90 mph (144.84 km/h)92.78 mph (149.32 km/h)
95 mph (152.89 km/h)97.94 mph (157.62 km/h)
100 mph (160.93 km/h)103.09 mph (165.91 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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