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 110/100r18 Tire Comparison Side By Side
  80/100-21 110/100-18 Difference
Diameter inches (mm) 27.3 (693.4) 26.66 (677.2) -0.64 (-16.2) -2.3%
Width inches (mm) 3.15 (80) 4.33 (110) 1.18 (30) 37.5%
Circum. inches (mm) 85.76 (2178.38) 83.76 (2127.49) -2 (-50.89) -2.3%
Sidewall Height inches (mm) 3.15 (80) 4.33 (110) 1.18 (30) 37.5%
Revolutions per mile (km) 738.78 (459.06) 756.45 (470.04) 17.67 (10.98) 2.4%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.53 mph (31.43 km/h)
25 mph (40.23 km/h)24.42 mph (39.29 km/h)
30 mph (48.28 km/h)29.3 mph (47.15 km/h)
35 mph (56.33 km/h)34.18 mph (55.01 km/h)
40 mph (64.37 km/h)39.07 mph (62.87 km/h)
45 mph (72.42 km/h)43.95 mph (70.73 km/h)
50 mph (80.47 km/h)48.83 mph (78.59 km/h)
55 mph (88.51 km/h)53.72 mph (86.45 km/h)
60 mph (96.56 km/h)58.6 mph (94.3 km/h)
65 mph (104.61 km/h)63.48 mph (102.16 km/h)
70 mph (112.65 km/h)68.36 mph (110.02 km/h)
75 mph (120.7 km/h)73.25 mph (117.88 km/h)
80 mph (128.75 km/h)78.13 mph (125.74 km/h)
85 mph (136.79 km/h)83.01 mph (133.6 km/h)
90 mph (144.84 km/h)87.9 mph (141.46 km/h)
95 mph (152.89 km/h)92.78 mph (149.32 km/h)
100 mph (160.93 km/h)97.66 mph (157.17 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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