What size is 255 40R20 in inches?
R20 tires have a diameter of 28 (712 mm), a tread width of 10 (255 mm), and a wheel diameter of 20 (508 mm). The sidewall of the tire is 4 (102 mm), and the tire’s circumference is 87. Therefore, the tire size 255/40R20 can be expressed in inches as roughly 10 inches wide, 4 inches tall, and designed to fit a 20-inch wheel rim.A 33×12. R20 tire measures exactly 33 inches in diameter, 12. The metric equivalent is approximately 318/60R20, with 305/55R20 being the closest available alternative size.The width difference between 225, 245, and 265 sizes directly affects how the car behaves. Tires that are 225mm wide provide the lightest and most agile steering.A tire number, such as 245/45R18, breaks down as follows: 245 (or 255): This number refers to the section width of the tire, measured in millimeters from sidewall to sidewall; thus, a 255 tire is 10mm wider than a 245 tire. This is the aspect ratio; the sidewall height of the tire as a percentage of its width.