Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
235/45r20 vs 235/55r20 Tire Comparison Side By Side
  235/45-20 235/55-20 Difference
Diameter inches (mm) 28.33 (719.5) 30.18 (766.5) 1.85 (47) 6.5%
Width inches (mm) 9.25 (235) 9.25 (235) 0 (0) 0%
Circum. inches (mm) 88.99 (2260.38) 94.8 (2408.03) 5.81 (147.65) 6.5%
Sidewall Height inches (mm) 4.16 (105.75) 5.09 (129.25) 0.93 (23.5) 22.2%
Revolutions per mile (km) 711.98 (442.4) 668.32 (415.28) -43.66 (-27.13) -6.1%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)21.31 mph (34.29 km/h)
25 mph (40.23 km/h)26.63 mph (42.86 km/h)
30 mph (48.28 km/h)31.96 mph (51.43 km/h)
35 mph (56.33 km/h)37.29 mph (60.01 km/h)
40 mph (64.37 km/h)42.61 mph (68.58 km/h)
45 mph (72.42 km/h)47.94 mph (77.15 km/h)
50 mph (80.47 km/h)53.27 mph (85.72 km/h)
55 mph (88.51 km/h)58.59 mph (94.3 km/h)
60 mph (96.56 km/h)63.92 mph (102.87 km/h)
65 mph (104.61 km/h)69.25 mph (111.44 km/h)
70 mph (112.65 km/h)74.57 mph (120.01 km/h)
75 mph (120.7 km/h)79.9 mph (128.59 km/h)
80 mph (128.75 km/h)85.23 mph (137.16 km/h)
85 mph (136.79 km/h)90.55 mph (145.73 km/h)
90 mph (144.84 km/h)95.88 mph (154.3 km/h)
95 mph (152.89 km/h)101.21 mph (162.88 km/h)
100 mph (160.93 km/h)106.53 mph (171.45 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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