The first number 245 is the tire width in millimeters. The 2nd number 60 is used to calculate the sidewall height or "aspect ratio", by percentage. So, the sidewall height of a 245/60 R 18 tire is 60% of 245 = 192. The 3rd number 18 (generally preceded by an "R") is Rim Diameter in inches. This is the diameter of the rims bead seat base, not Tire Size and Comparison Calculator calculate tire diameter from code and compare speedometer differences for tire sizes. The first number 245 is the tire width in millimeters. The 2nd number 55 is used to calculate the sidewall height or "aspect ratio", by percentage. So, the sidewall height of a 245/55 R 18 tire is 60% of 245 = 192. In the tire comparison table above, you can see a detailed calculation of the size difference between 235/65 R18 and 235/60 R18 tire. The calculation results are presented in the form of visual infographics, on which tire with size 235/65 R18 is on top, and tire with size 235/60 R18 below. Both in the table and in the graph, the tires are In the tire comparison table above, you can see a detailed calculation of the size difference between 235/55 R19 and 235/60 R18 tire. The calculation results are presented in the form of visual infographics, on which tire with size 235/55 R19 is on top, and tire with size 235/60 R18 below. Both in the table and in the graph, the tires are The first number 235 is the tire width in millimeters. The 2nd number 55 is used to calculate the sidewall height or "aspect ratio", by percentage. So, the sidewall height of a 235/55 R 18 tire is 60% of 235 = 192. The 3rd number 18 (generally preceded by an "R") is Rim Diameter in inches. This is the diameter of the rims bead seat base, not For sale Winter tires Imperial Eco norch suv, 235/65/R17, In stock: 4 pc., Tread depth: 9 mm., Condition: Used, Installation is possible. 170 €/set 31/10/2022 Riga, Jugla 235/60-R17 tires are 1.56 inches (39.6 mm) larger in diameter than 155/70-R18 tires and the speedometer difference is 5.5%. In the tire comparison table above, you can see a detailed calculation of the size difference between 235/65 R18 and 275/65 R18 tire. The calculation results are presented in the form of visual infographics, on which tire with size 235/65 R18 is on top, and tire with size 275/65 R18 below. Both in the table and in the graph, the tires are 135/90-R17 tires are 0.24 inches (6.1 mm) larger in diameter than 235/45-R18 tires and the speedometer difference is 0.9%. Tire Size and Comparison Calculator calculate tire diameter from code and compare speedometer differences for tire sizes. The first number 255 is the tire width in millimeters. The 2nd number 55 is used to calculate the sidewall height or "aspect ratio", by percentage. So, the sidewall height of a 255/55 R 18 tire is 60% of 255 = 192. 80keJn.