Tire Size Calculator

Tire Size Finder (optional):

Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
245/55r18 vs 245/40r18 Tire Comparison Side By Side
  245/55-18 245/40-18 Difference
Diameter inches (mm) 28.61 (726.7) 25.72 (653.2) -2.89 (-73.5) -10.1%
Width inches (mm) 9.65 (245) 9.65 (245) 0 (0) 0%
Circum. inches (mm) 89.88 (2283) 80.79 (2052.09) -9.09 (-230.91) -10.1%
Sidewall Height inches (mm) 5.31 (134.75) 3.86 (98) -1.45 (-36.75) -27.3%
Revolutions per mile (km) 704.93 (438.02) 784.25 (487.31) 79.32 (49.29) 11.3%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)17.98 mph (28.93 km/h)
25 mph (40.23 km/h)22.47 mph (36.16 km/h)
30 mph (48.28 km/h)26.97 mph (43.4 km/h)
35 mph (56.33 km/h)31.46 mph (50.63 km/h)
40 mph (64.37 km/h)35.95 mph (57.86 km/h)
45 mph (72.42 km/h)40.45 mph (65.1 km/h)
50 mph (80.47 km/h)44.94 mph (72.33 km/h)
55 mph (88.51 km/h)49.44 mph (79.56 km/h)
60 mph (96.56 km/h)53.93 mph (86.79 km/h)
65 mph (104.61 km/h)58.43 mph (94.03 km/h)
70 mph (112.65 km/h)62.92 mph (101.26 km/h)
75 mph (120.7 km/h)67.41 mph (108.49 km/h)
80 mph (128.75 km/h)71.91 mph (115.73 km/h)
85 mph (136.79 km/h)76.4 mph (122.96 km/h)
90 mph (144.84 km/h)80.9 mph (130.19 km/h)
95 mph (152.89 km/h)85.39 mph (137.42 km/h)
100 mph (160.93 km/h)89.89 mph (144.66 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
19962318249726072726281129043015316833213490362638734144435744934569484952406089
Better Fuel Economy Factory Ratios Increased Power

Most Popular 245/55-R18 Comparisons

To Top