Tire Size Calculator

Tire Size Finder (optional):

Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
245/30r20 vs 255/30r20 Tire Comparison Side By Side
  245/30-20 255/30-20 Difference
Diameter inches (mm) 25.79 (655) 26.02 (661) 0.24 (6) 0.9%
Width inches (mm) 9.65 (245) 10.04 (255) 0.39 (10) 4.1%
Circum. inches (mm) 81.01 (2057.74) 81.76 (2076.59) 0.74 (18.85) 0.9%
Sidewall Height inches (mm) 2.89 (73.5) 3.01 (76.5) 0.12 (3) 4.1%
Revolutions per mile (km) 782.09 (485.97) 774.99 (481.56) -7.1 (-4.41) -0.9%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.18 mph (32.48 km/h)
25 mph (40.23 km/h)25.23 mph (40.6 km/h)
30 mph (48.28 km/h)30.27 mph (48.72 km/h)
35 mph (56.33 km/h)35.32 mph (56.84 km/h)
40 mph (64.37 km/h)40.37 mph (64.96 km/h)
45 mph (72.42 km/h)45.41 mph (73.08 km/h)
50 mph (80.47 km/h)50.46 mph (81.2 km/h)
55 mph (88.51 km/h)55.5 mph (89.32 km/h)
60 mph (96.56 km/h)60.55 mph (97.45 km/h)
65 mph (104.61 km/h)65.6 mph (105.57 km/h)
70 mph (112.65 km/h)70.64 mph (113.69 km/h)
75 mph (120.7 km/h)75.69 mph (121.81 km/h)
80 mph (128.75 km/h)80.73 mph (129.93 km/h)
85 mph (136.79 km/h)85.78 mph (138.05 km/h)
90 mph (144.84 km/h)90.82 mph (146.17 km/h)
95 mph (152.89 km/h)95.87 mph (154.29 km/h)
100 mph (160.93 km/h)100.92 mph (162.41 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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