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 285/30r20 Tire Comparison Side By Side
  355/25-21 285/30-20 Difference
Diameter inches (mm) 27.99 (710.9) 26.73 (679) -1.26 (-31.9) -4.5%
Width inches (mm) 13.98 (355) 11.22 (285) -2.76 (-70) -19.7%
Circum. inches (mm) 87.93 (2233.36) 83.98 (2133.14) -3.95 (-100.22) -4.5%
Sidewall Height inches (mm) 3.49 (88.75) 3.37 (85.5) -0.13 (-3.25) -3.7%
Revolutions per mile (km) 720.59 (447.76) 754.45 (468.79) 33.85 (21.04) 4.7%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.1 mph (30.74 km/h)
25 mph (40.23 km/h)23.88 mph (38.43 km/h)
30 mph (48.28 km/h)28.65 mph (46.11 km/h)
35 mph (56.33 km/h)33.43 mph (53.8 km/h)
40 mph (64.37 km/h)38.21 mph (61.49 km/h)
45 mph (72.42 km/h)42.98 mph (69.17 km/h)
50 mph (80.47 km/h)47.76 mph (76.86 km/h)
55 mph (88.51 km/h)52.53 mph (84.54 km/h)
60 mph (96.56 km/h)57.31 mph (92.23 km/h)
65 mph (104.61 km/h)62.08 mph (99.91 km/h)
70 mph (112.65 km/h)66.86 mph (107.6 km/h)
75 mph (120.7 km/h)71.63 mph (115.28 km/h)
80 mph (128.75 km/h)76.41 mph (122.97 km/h)
85 mph (136.79 km/h)81.19 mph (130.66 km/h)
90 mph (144.84 km/h)85.96 mph (138.34 km/h)
95 mph (152.89 km/h)90.74 mph (146.03 km/h)
100 mph (160.93 km/h)95.51 mph (153.71 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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