Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
305/45r20 vs 305/50r17 Tire Comparison Side By Side
  305/45-20 305/50-17 Difference
Diameter inches (mm) 30.81 (782.5) 29.01 (736.8) -1.8 (-45.7) -5.8%
Width inches (mm) 12.01 (305) 12.01 (305) 0 (0) 0%
Circum. inches (mm) 96.78 (2458.3) 91.13 (2314.73) -5.65 (-143.57) -5.8%
Sidewall Height inches (mm) 5.4 (137.25) 6 (152.5) 0.6 (15.25) 11.1%
Revolutions per mile (km) 654.66 (406.79) 695.26 (432.02) 40.61 (25.23) 6.2%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)18.83 mph (30.31 km/h)
25 mph (40.23 km/h)23.54 mph (37.88 km/h)
30 mph (48.28 km/h)28.25 mph (45.46 km/h)
35 mph (56.33 km/h)32.96 mph (53.04 km/h)
40 mph (64.37 km/h)37.66 mph (60.61 km/h)
45 mph (72.42 km/h)42.37 mph (68.19 km/h)
50 mph (80.47 km/h)47.08 mph (75.77 km/h)
55 mph (88.51 km/h)51.79 mph (83.34 km/h)
60 mph (96.56 km/h)56.5 mph (90.92 km/h)
65 mph (104.61 km/h)61.2 mph (98.5 km/h)
70 mph (112.65 km/h)65.91 mph (106.07 km/h)
75 mph (120.7 km/h)70.62 mph (113.65 km/h)
80 mph (128.75 km/h)75.33 mph (121.23 km/h)
85 mph (136.79 km/h)80.04 mph (128.81 km/h)
90 mph (144.84 km/h)84.74 mph (136.38 km/h)
95 mph (152.89 km/h)89.45 mph (143.96 km/h)
100 mph (160.93 km/h)94.16 mph (151.54 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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