Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
265/35r21 vs 305/30r21 Tire Comparison Side By Side
  265/35-21 305/30-21 Difference
Diameter inches (mm) 28.3 (718.9) 28.2 (716.4) -0.1 (-2.5) -0.3%
Width inches (mm) 10.43 (265) 12.01 (305) 1.57 (40) 15.1%
Circum. inches (mm) 88.92 (2258.49) 88.61 (2250.64) -0.31 (-7.85) -0.3%
Sidewall Height inches (mm) 3.65 (92.75) 3.6 (91.5) -0.05 (-1.25) -1.3%
Revolutions per mile (km) 712.57 (442.77) 715.06 (444.32) 2.49 (1.55) 0.3%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.93 mph (32.08 km/h)
25 mph (40.23 km/h)24.91 mph (40.09 km/h)
30 mph (48.28 km/h)29.9 mph (48.11 km/h)
35 mph (56.33 km/h)34.88 mph (56.13 km/h)
40 mph (64.37 km/h)39.86 mph (64.15 km/h)
45 mph (72.42 km/h)44.84 mph (72.17 km/h)
50 mph (80.47 km/h)49.83 mph (80.19 km/h)
55 mph (88.51 km/h)54.81 mph (88.21 km/h)
60 mph (96.56 km/h)59.79 mph (96.23 km/h)
65 mph (104.61 km/h)64.77 mph (104.24 km/h)
70 mph (112.65 km/h)69.76 mph (112.26 km/h)
75 mph (120.7 km/h)74.74 mph (120.28 km/h)
80 mph (128.75 km/h)79.72 mph (128.3 km/h)
85 mph (136.79 km/h)84.7 mph (136.32 km/h)
90 mph (144.84 km/h)89.69 mph (144.34 km/h)
95 mph (152.89 km/h)94.67 mph (152.36 km/h)
100 mph (160.93 km/h)99.65 mph (160.38 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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