Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
80/100r21 vs 80/80r21 Tire Comparison Side By Side
  80/100-21 80/80-21 Difference
Diameter inches (mm) 27.3 (693.4) 26.04 (661.4) -1.26 (-32) -4.6%
Width inches (mm) 3.15 (80) 3.15 (80) 0 (0) 0%
Circum. inches (mm) 85.76 (2178.38) 81.81 (2077.85) -3.96 (-100.53) -4.6%
Sidewall Height inches (mm) 3.15 (80) 2.52 (64) -0.63 (-16) -20%
Revolutions per mile (km) 738.78 (459.06) 774.52 (481.27) 35.74 (22.21) 4.8%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.08 mph (30.7 km/h)
25 mph (40.23 km/h)23.85 mph (38.38 km/h)
30 mph (48.28 km/h)28.62 mph (46.05 km/h)
35 mph (56.33 km/h)33.38 mph (53.73 km/h)
40 mph (64.37 km/h)38.15 mph (61.4 km/h)
45 mph (72.42 km/h)42.92 mph (69.08 km/h)
50 mph (80.47 km/h)47.69 mph (76.75 km/h)
55 mph (88.51 km/h)52.46 mph (84.43 km/h)
60 mph (96.56 km/h)57.23 mph (92.1 km/h)
65 mph (104.61 km/h)62 mph (99.78 km/h)
70 mph (112.65 km/h)66.77 mph (107.46 km/h)
75 mph (120.7 km/h)71.54 mph (115.13 km/h)
80 mph (128.75 km/h)76.31 mph (122.81 km/h)
85 mph (136.79 km/h)81.08 mph (130.48 km/h)
90 mph (144.84 km/h)85.85 mph (138.16 km/h)
95 mph (152.89 km/h)90.62 mph (145.83 km/h)
100 mph (160.93 km/h)95.39 mph (153.51 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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