Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
315/35r20 vs 305/40r20 Tire Comparison Side By Side
  315/35-20 305/40-20 Difference
Diameter inches (mm) 28.68 (728.5) 29.61 (752) 0.93 (23.5) 3.2%
Width inches (mm) 12.4 (315) 12.01 (305) -0.39 (-10) -3.2%
Circum. inches (mm) 90.1 (2288.65) 93.01 (2362.48) 2.91 (73.83) 3.2%
Sidewall Height inches (mm) 4.34 (110.25) 4.8 (122) 0.46 (11.75) 10.7%
Revolutions per mile (km) 703.18 (436.94) 681.21 (423.28) -21.97 (-13.65) -3.1%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.65 mph (33.23 km/h)
25 mph (40.23 km/h)25.81 mph (41.53 km/h)
30 mph (48.28 km/h)30.97 mph (49.84 km/h)
35 mph (56.33 km/h)36.13 mph (58.14 km/h)
40 mph (64.37 km/h)41.29 mph (66.45 km/h)
45 mph (72.42 km/h)46.45 mph (74.76 km/h)
50 mph (80.47 km/h)51.61 mph (83.06 km/h)
55 mph (88.51 km/h)56.77 mph (91.37 km/h)
60 mph (96.56 km/h)61.94 mph (99.68 km/h)
65 mph (104.61 km/h)67.1 mph (107.98 km/h)
70 mph (112.65 km/h)72.26 mph (116.29 km/h)
75 mph (120.7 km/h)77.42 mph (124.59 km/h)
80 mph (128.75 km/h)82.58 mph (132.9 km/h)
85 mph (136.79 km/h)87.74 mph (141.21 km/h)
90 mph (144.84 km/h)92.9 mph (149.51 km/h)
95 mph (152.89 km/h)98.06 mph (157.82 km/h)
100 mph (160.93 km/h)103.23 mph (166.13 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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