We've been helping people find the right tires, wheels and performance parts since 1979. If you're looking for the best and most accurate information on all things tires, you've come to the right place.
A tire's most important job is to carry the load required of it, and the load range/ply rating branded on the tire's sidewall indicates how much load the tire is designed to carry (at a specific pressure). Whenever changing tire sizes or from one tire type to another, it's important to ensure...
A load index is an assigned numerical value that signifies a tire's maximum load carrying capacity. They're useful to help compare load carrying capacity of different-sized tires, and as you might expect, the higher the tire's load index number, the greater its load carrying capacity. Using the...
During a trip to Pirelli's facilities in Europe, several members of the Tire Rack team had the opportunity to visit their tire plant in Brueberg, Germany. Opened in 1963, this tire manufacturing facility is unique because it now features multiple generations of tire manufacturing equipment...
Tire and wheel manufacturers initially formed regional associations to establish interchangeability standards for tires, rims and allied parts for the guidance of manufacturers, as well as to establish standards for the designers of motor vehicles, aircraft and other wheeled vehicles. These...
Country of Origin Although regularly updated, the country of origin for any tire may vary from the country shown here. Unfortunately, we cannot accommodate requests for tires with a specific country of origin.
Revolutions Per Mile Revolutions per mile indicates the number of times a tire revolves while it covers the distance of one mile. Depending on the tire manufacturer, revolutions per mile may be either measured in a laboratory or derived from calculations based on their previous test...
Overall Diameter A tire's overall diameter is the outer diameter of the tire measured in the center of the tread. This measurement is made without any load placed upon the tire and after the tire has been properly mounted on its industry assigned measuring rim and has been inflated and reset...
Tread Width Measuring Tread width is typically thought of as a measurement between the outboard and inboard edges of a new tire's tread design. Ideally it approximates the width of the tread that comes into contact with the road. Unfortunately measuring tire tread width isn't as simple as...
Section Width A tire's section width (also called "cross section width") is the measurement of the tire's width from its inner sidewall to its outer sidewall (excluding any protective ribs, decorations or raised letters) at the widest point. This measurement is made without any load placed...
Measuring Rim Width The measuring rim width is the industry standardized rim width upon which the tire must be mounted in order to confirm it meets its dimensional targets. Because the width of the rim will influence the width of the tire, a standard rim width for every tire size is assigned...
Much like your foot can sometimes fit in a half size up or down shoe, tires have a range of rim widths they can be mounted on while still performing as designed. Likewise, similarly to how a person typically knows their "shoe size," tires have a measuring rim width from which the tire’s...
Tread Depth Tread depth is a vertical measurement between the top of the tread rubber to the bottom of the tire's deepest grooves. In the United States, tread depth is measured in 32nds of an inch. Because it is difficult to accurately measure tread depth with a ruler, tread depth is best...
Maximum Inflation Pressure A tire's maximum inflation pressure is the highest "cold" inflation pressure that the tire is designed to contain. However the tire's maximum inflation pressure should only be used when called for on the vehicle's tire placard or in the vehicle's owners manual. It is...
Maximum Load A tire's maximum load is the most weight the tire is designed to carry. Since a tire's load carrying capacity is related to the tire's size and construction and how much inflation pressure is actually used, maximum loads are rated with the tire inflated to an industry assigned...
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