Tires are among the most technologically advanced systems in any automobile. They play a major role in your vehicle’s comfort and performance. Although tires are not available in all sizes, they can be found in many shapes and come with unique identification information.
Bridgestone Firestone has provided the following rundown to help you figure out what all those numbers actually mean.
For example, if your tire’s size designation reads P185/70R14 87S:
* “P”P-Metric is an acronym. This is the most widely used system to identify passenger tires sizes. Another is European-Metric, also known as Euro-Metric.
* “185”The tire’s section width is measured in millimeters. This measurement is measured from the tire’s sidewall to the opposite sidewall after it has been mounted and properly inflated.
* “70” designates aspect ratio. This is also known as the profile, or series. It’s the ratio of tire’s section height and section width. This means that the 70 series tire is 70% taller than it is wide.
* “R”Refers to the type of tire’s construction. Radial construction has been dominant in the American market since 1970, when rising gas prices led to increased demand for radial tire. They are more fuel efficient than their predecessors, the bias tires. This is due to their low rolling resistance.
* “14”The rim diameter is in inches. This simple number tells you that the tire must fit onto a 14-inch wheel. Don’t let this fool you. Every 14-inch tire will not fit every rim. It is important to consider the width of your rim.
* “87”This is the load index. The tire’s specified maximum pressure for inflation, 35 psi, is used to reference the load index. This indicates the tire’s maximum weight in pounds at that pressure. This tire will support 1,201 pounds at 35 Psi.
* “S”The speed rating is the measurement of a tire’s ability to travel at a predetermined speed. This alphabetical system describes a tire’s ability to travel at predetermined speeds. It allows vehicle owners to compare performance capabilities between different tires.
For more tire information, visit www.tiresafety.com.
