Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
305/70r20 vs 35/12.5r20 Tire Comparison Side By Side
  305/70-20 35/12.5-20 Difference
Diameter inches (mm) 36.81 (935) 35.02 (889.6) -1.79 (-45.4) -4.9%
Width inches (mm) 12.01 (305) 12.52 (318) 0.51 (13) 4.3%
Circum. inches (mm) 115.65 (2937.39) 110.03 (2794.76) -5.62 (-142.63) -4.9%
Sidewall Height inches (mm) 8.41 (213.5) 7.51 (190.8) -0.89 (-22.7) -10.6%
Revolutions per mile (km) 547.88 (340.44) 575.84 (357.81) 27.96 (17.37) 5.1%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.03 mph (30.62 km/h)
25 mph (40.23 km/h)23.79 mph (38.28 km/h)
30 mph (48.28 km/h)28.54 mph (45.94 km/h)
35 mph (56.33 km/h)33.3 mph (53.59 km/h)
40 mph (64.37 km/h)38.06 mph (61.25 km/h)
45 mph (72.42 km/h)42.81 mph (68.9 km/h)
50 mph (80.47 km/h)47.57 mph (76.56 km/h)
55 mph (88.51 km/h)52.33 mph (84.22 km/h)
60 mph (96.56 km/h)57.09 mph (91.87 km/h)
65 mph (104.61 km/h)61.84 mph (99.53 km/h)
70 mph (112.65 km/h)66.6 mph (107.18 km/h)
75 mph (120.7 km/h)71.36 mph (114.84 km/h)
80 mph (128.75 km/h)76.12 mph (122.5 km/h)
85 mph (136.79 km/h)80.87 mph (130.15 km/h)
90 mph (144.84 km/h)85.63 mph (137.81 km/h)
95 mph (152.89 km/h)90.39 mph (145.46 km/h)
100 mph (160.93 km/h)95.14 mph (153.12 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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