Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
355/25r21 vs 345/30r20 Tire Comparison Side By Side
  355/25-21 345/30-20 Difference
Diameter inches (mm) 27.99 (710.9) 28.15 (715) 0.16 (4.1) 0.6%
Width inches (mm) 13.98 (355) 13.58 (345) -0.39 (-10) -2.8%
Circum. inches (mm) 87.93 (2233.36) 88.43 (2246.24) 0.51 (12.88) 0.6%
Sidewall Height inches (mm) 3.49 (88.75) 4.07 (103.5) 0.58 (14.75) 16.6%
Revolutions per mile (km) 720.59 (447.76) 716.46 (445.19) -4.13 (-2.57) -0.6%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.12 mph (32.37 km/h)
25 mph (40.23 km/h)25.14 mph (40.47 km/h)
30 mph (48.28 km/h)30.17 mph (48.56 km/h)
35 mph (56.33 km/h)35.2 mph (56.65 km/h)
40 mph (64.37 km/h)40.23 mph (64.75 km/h)
45 mph (72.42 km/h)45.26 mph (72.84 km/h)
50 mph (80.47 km/h)50.29 mph (80.93 km/h)
55 mph (88.51 km/h)55.32 mph (89.02 km/h)
60 mph (96.56 km/h)60.35 mph (97.12 km/h)
65 mph (104.61 km/h)65.37 mph (105.21 km/h)
70 mph (112.65 km/h)70.4 mph (113.3 km/h)
75 mph (120.7 km/h)75.43 mph (121.4 km/h)
80 mph (128.75 km/h)80.46 mph (129.49 km/h)
85 mph (136.79 km/h)85.49 mph (137.58 km/h)
90 mph (144.84 km/h)90.52 mph (145.68 km/h)
95 mph (152.89 km/h)95.55 mph (153.77 km/h)
100 mph (160.93 km/h)100.58 mph (161.86 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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