Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
305/30r21 vs 305/35r19 Tire Comparison Side By Side
  305/30-21 305/35-19 Difference
Diameter inches (mm) 28.2 (716.4) 27.41 (696.1) -0.8 (-20.3) -2.8%
Width inches (mm) 12.01 (305) 12.01 (305) 0 (0) 0%
Circum. inches (mm) 88.61 (2250.64) 86.1 (2186.86) -2.51 (-63.77) -2.8%
Sidewall Height inches (mm) 3.6 (91.5) 4.2 (106.75) 0.6 (15.25) 16.7%
Revolutions per mile (km) 715.06 (444.32) 735.91 (457.28) 20.85 (12.96) 2.9%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.43 mph (31.27 km/h)
25 mph (40.23 km/h)24.29 mph (39.09 km/h)
30 mph (48.28 km/h)29.15 mph (46.91 km/h)
35 mph (56.33 km/h)34.01 mph (54.73 km/h)
40 mph (64.37 km/h)38.87 mph (62.55 km/h)
45 mph (72.42 km/h)43.72 mph (70.37 km/h)
50 mph (80.47 km/h)48.58 mph (78.19 km/h)
55 mph (88.51 km/h)53.44 mph (86.01 km/h)
60 mph (96.56 km/h)58.3 mph (93.82 km/h)
65 mph (104.61 km/h)63.16 mph (101.64 km/h)
70 mph (112.65 km/h)68.02 mph (109.46 km/h)
75 mph (120.7 km/h)72.87 mph (117.28 km/h)
80 mph (128.75 km/h)77.73 mph (125.1 km/h)
85 mph (136.79 km/h)82.59 mph (132.92 km/h)
90 mph (144.84 km/h)87.45 mph (140.74 km/h)
95 mph (152.89 km/h)92.31 mph (148.56 km/h)
100 mph (160.93 km/h)97.17 mph (156.37 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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