Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
325/25r21 vs 345/35r24 Tire Comparison Side By Side
  325/25-21 345/35-24 Difference
Diameter inches (mm) 27.4 (695.9) 33.51 (851.1) 6.11 (155.2) 22.3%
Width inches (mm) 12.8 (325) 13.58 (345) 0.79 (20) 6.2%
Circum. inches (mm) 86.07 (2186.23) 105.27 (2673.81) 19.2 (487.58) 22.3%
Sidewall Height inches (mm) 3.2 (81.25) 4.75 (120.75) 1.56 (39.5) 48.6%
Revolutions per mile (km) 736.13 (457.41) 601.89 (374) -134.23 (-83.41) -18.2%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)24.46 mph (39.37 km/h)
25 mph (40.23 km/h)30.58 mph (49.21 km/h)
30 mph (48.28 km/h)36.69 mph (59.05 km/h)
35 mph (56.33 km/h)42.81 mph (68.89 km/h)
40 mph (64.37 km/h)48.92 mph (78.73 km/h)
45 mph (72.42 km/h)55.04 mph (88.57 km/h)
50 mph (80.47 km/h)61.15 mph (98.41 km/h)
55 mph (88.51 km/h)67.27 mph (108.25 km/h)
60 mph (96.56 km/h)73.38 mph (118.1 km/h)
65 mph (104.61 km/h)79.5 mph (127.94 km/h)
70 mph (112.65 km/h)85.61 mph (137.78 km/h)
75 mph (120.7 km/h)91.73 mph (147.62 km/h)
80 mph (128.75 km/h)97.84 mph (157.46 km/h)
85 mph (136.79 km/h)103.96 mph (167.3 km/h)
90 mph (144.84 km/h)110.07 mph (177.14 km/h)
95 mph (152.89 km/h)116.19 mph (186.99 km/h)
100 mph (160.93 km/h)122.3 mph (196.83 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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