Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
345/35r18 vs 345/40r18 Tire Comparison Side By Side
  345/35-18 345/40-18 Difference
Diameter inches (mm) 27.51 (698.7) 28.87 (733.2) 1.36 (34.5) 4.9%
Width inches (mm) 13.58 (345) 13.58 (345) 0 (0) 0%
Circum. inches (mm) 86.42 (2195.03) 90.69 (2303.42) 4.27 (108.38) 4.9%
Sidewall Height inches (mm) 4.75 (120.75) 5.43 (138) 0.68 (17.25) 14.3%
Revolutions per mile (km) 733.18 (455.57) 698.68 (434.14) -34.5 (-21.44) -4.7%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.99 mph (33.78 km/h)
25 mph (40.23 km/h)26.23 mph (42.22 km/h)
30 mph (48.28 km/h)31.48 mph (50.66 km/h)
35 mph (56.33 km/h)36.73 mph (59.11 km/h)
40 mph (64.37 km/h)41.98 mph (67.55 km/h)
45 mph (72.42 km/h)47.22 mph (76 km/h)
50 mph (80.47 km/h)52.47 mph (84.44 km/h)
55 mph (88.51 km/h)57.72 mph (92.88 km/h)
60 mph (96.56 km/h)62.96 mph (101.33 km/h)
65 mph (104.61 km/h)68.21 mph (109.77 km/h)
70 mph (112.65 km/h)73.46 mph (118.22 km/h)
75 mph (120.7 km/h)78.7 mph (126.66 km/h)
80 mph (128.75 km/h)83.95 mph (135.1 km/h)
85 mph (136.79 km/h)89.2 mph (143.55 km/h)
90 mph (144.84 km/h)94.44 mph (151.99 km/h)
95 mph (152.89 km/h)99.69 mph (160.44 km/h)
100 mph (160.93 km/h)104.94 mph (168.88 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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