Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
305/35r20 vs 305/30r20 Tire Comparison Side By Side
  305/35-20 305/30-20 Difference
Diameter inches (mm) 28.41 (721.5) 27.2 (691) -1.2 (-30.5) -4.2%
Width inches (mm) 12.01 (305) 12.01 (305) 0 (0) 0%
Circum. inches (mm) 89.24 (2266.66) 85.47 (2170.84) -3.77 (-95.82) -4.2%
Sidewall Height inches (mm) 4.2 (106.75) 3.6 (91.5) -0.6 (-15.25) -14.3%
Revolutions per mile (km) 710.01 (441.18) 741.35 (460.65) 31.34 (19.47) 4.4%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.15 mph (30.83 km/h)
25 mph (40.23 km/h)23.94 mph (38.53 km/h)
30 mph (48.28 km/h)28.73 mph (46.24 km/h)
35 mph (56.33 km/h)33.52 mph (53.95 km/h)
40 mph (64.37 km/h)38.31 mph (61.65 km/h)
45 mph (72.42 km/h)43.1 mph (69.36 km/h)
50 mph (80.47 km/h)47.89 mph (77.07 km/h)
55 mph (88.51 km/h)52.67 mph (84.77 km/h)
60 mph (96.56 km/h)57.46 mph (92.48 km/h)
65 mph (104.61 km/h)62.25 mph (100.19 km/h)
70 mph (112.65 km/h)67.04 mph (107.89 km/h)
75 mph (120.7 km/h)71.83 mph (115.6 km/h)
80 mph (128.75 km/h)76.62 mph (123.31 km/h)
85 mph (136.79 km/h)81.41 mph (131.01 km/h)
90 mph (144.84 km/h)86.2 mph (138.72 km/h)
95 mph (152.89 km/h)90.98 mph (146.42 km/h)
100 mph (160.93 km/h)95.77 mph (154.13 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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