Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
275/35r21 vs 305/30r21 Tire Comparison Side By Side
  275/35-21 305/30-21 Difference
Diameter inches (mm) 28.58 (725.9) 28.2 (716.4) -0.37 (-9.5) -1.3%
Width inches (mm) 10.83 (275) 12.01 (305) 1.18 (30) 10.9%
Circum. inches (mm) 89.78 (2280.48) 88.61 (2250.64) -1.18 (-29.85) -1.3%
Sidewall Height inches (mm) 3.79 (96.25) 3.6 (91.5) -0.19 (-4.75) -4.9%
Revolutions per mile (km) 705.7 (438.5) 715.06 (444.32) 9.36 (5.81) 1.3%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.74 mph (31.77 km/h)
25 mph (40.23 km/h)24.67 mph (39.71 km/h)
30 mph (48.28 km/h)29.61 mph (47.65 km/h)
35 mph (56.33 km/h)34.54 mph (55.59 km/h)
40 mph (64.37 km/h)39.48 mph (63.53 km/h)
45 mph (72.42 km/h)44.41 mph (71.47 km/h)
50 mph (80.47 km/h)49.35 mph (79.41 km/h)
55 mph (88.51 km/h)54.28 mph (87.36 km/h)
60 mph (96.56 km/h)59.21 mph (95.3 km/h)
65 mph (104.61 km/h)64.15 mph (103.24 km/h)
70 mph (112.65 km/h)69.08 mph (111.18 km/h)
75 mph (120.7 km/h)74.02 mph (119.12 km/h)
80 mph (128.75 km/h)78.95 mph (127.06 km/h)
85 mph (136.79 km/h)83.89 mph (135 km/h)
90 mph (144.84 km/h)88.82 mph (142.95 km/h)
95 mph (152.89 km/h)93.76 mph (150.89 km/h)
100 mph (160.93 km/h)98.69 mph (158.83 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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