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# What Is the Difference Between 275/45R20 106V and 275/45R20 109V?

by Andy Josiah

The numbers 275/45R20 106V and 275/45R20 109V are two versions of the same tire size. Found on the tire's sidewall, the numbers represent a bit of information about the ring-shaped rubber covering around the wheel rim of an automobile; this is particularly essential for replacing and installing a tire. In this case, the only difference between the 275/45R20 106V tire and the 275/45R20 109V tire is the load index.

### Section Width

The first three numbers, "275," represent the tire's section width, which is the measurement -- in millimeters -- of the widest point of its outer sidewall to the widest point of its inner sidewall. So, that means that a 275/45R20 tire has a section width of 215 mm, which can be translated to 10.83 inches.

### Sidewall

The number "45" represents the sidewall aspect ratio, which is the ratio of the tire size's sidewall -- measured from the wheel rim to the tire tread -- to the section width. This indicator is expressed as a percentage, thus meaning that the 275/45R20 tire has a sidewall that is 45 percent of its section width. As for the sidewall itself, its height can be measured by multiplying the section width by the aspect ratio. Thus, the 275/45R20 tire has a sidewall height of 123.75 mm, or 4.87 inches.

### Construction and Tire/Wheel Diameter

The "R" after the sidewall digits indicated that the 275/45R20 is a radial tire. This means that it was made with the tire's cord plies "radiating" from the wheel's center, or are arranged at a 90-degree angle to the direction of travel. Notably, radial tires are the most commonly used types of automobile tires. The two digits that follow, "20," represent the paired tire and wheel diameter inscribed in inches. Thus, the 273/45R20 tire is a 20-inch tire, meant for application on a 20-inch wheel.