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 285/35r20 Tire Comparison Side By Side
  305/35-20 285/35-20 Difference
Diameter inches (mm) 28.41 (721.5) 27.85 (707.5) -0.55 (-14) -1.9%
Width inches (mm) 12.01 (305) 11.22 (285) -0.79 (-20) -6.6%
Circum. inches (mm) 89.24 (2266.66) 87.51 (2222.68) -1.73 (-43.98) -1.9%
Sidewall Height inches (mm) 4.2 (106.75) 3.93 (99.75) -0.28 (-7) -6.6%
Revolutions per mile (km) 710.01 (441.18) 724.06 (449.91) 14.05 (8.73) 2%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.61 mph (31.56 km/h)
25 mph (40.23 km/h)24.51 mph (39.45 km/h)
30 mph (48.28 km/h)29.42 mph (47.34 km/h)
35 mph (56.33 km/h)34.32 mph (55.23 km/h)
40 mph (64.37 km/h)39.22 mph (63.12 km/h)
45 mph (72.42 km/h)44.13 mph (71.02 km/h)
50 mph (80.47 km/h)49.03 mph (78.91 km/h)
55 mph (88.51 km/h)53.93 mph (86.8 km/h)
60 mph (96.56 km/h)58.84 mph (94.69 km/h)
65 mph (104.61 km/h)63.74 mph (102.58 km/h)
70 mph (112.65 km/h)68.64 mph (110.47 km/h)
75 mph (120.7 km/h)73.54 mph (118.36 km/h)
80 mph (128.75 km/h)78.45 mph (126.25 km/h)
85 mph (136.79 km/h)83.35 mph (134.14 km/h)
90 mph (144.84 km/h)88.25 mph (142.03 km/h)
95 mph (152.89 km/h)93.16 mph (149.92 km/h)
100 mph (160.93 km/h)98.06 mph (157.81 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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